Author Topic: Fluke 123 Scopemeter and battery replacement  (Read 53677 times)

0 Members and 1 Guest are viewing this topic.

Offline Cones

  • Regular Contributor
  • *
  • Posts: 62
  • Country: gb
Fluke 123 Scopemeter and battery replacement
« on: March 02, 2013, 03:25:46 pm »
Hi,

I bought a cheap Fluke 123 scopemeter from ebay with lines on the screen and a flat battery. No problem I thought, I can live with the lines and I will just get a new 3rd party battery for £15 from Amazon here in the UK.

This is where all the fun and games starts!

The original Fluke battery is a BP120 and is a 2000mAh NiCd unit. It would not charge in the scopemeter and would only maintain the unit for 30 second or so before it powered down.

The new replacement battery is made by Cameron Sino and is a BP130 Equivalent 3000mAh NiMh unit.

But on comparing the wiring on the 6 pin connector for the two batteries the new 3000mAh one is wired wrong and will not work at all in the scopemeter. As it was low cost and not worth the hassle of changing it. I have investigated further and resolved all of the problems with it.

This is the correct pin wiring for the scopemeter battery connector.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

So I swapped the connector pins round in the plug on the new battery and then the meter would power on with it. But it still would not charge fully or perform a battery refresh operation.

After a bit of Googling and a look at the Fluke service manual I found the above pinout information and I also discovered the correct resistance value for the NiMh battery.

I measured the value on my battery Identification resistor and I got a resistance of 0.8301 Meg Ohms not the 825 Ohms it is supposed to be. So the manufacturer not only wired the plug wrong they also compounded the problem by putting the wrong resistance value in as well!

So I have now cut open the heat shrink and corrected their mistakes as you can see in the pictures below.

Battery


Original and pending replacement resistor


Crap insulation on the opposite side of the original resistor


Removed resistance value


Replacement Resistance Value


Correct Plug wiring


Repaired and heatshrink added for a slightly better insulation


Red insulation tape as I have run out of larger heatshrink. This may get replaced in future if I can be bothered!


Original Battery pack


Refresh now detects the NiMh and changes from 12 (NiCd) to 19 Hours! Result.




 

Offline SeanB

  • Super Contributor
  • ***
  • Posts: 15429
  • Country: za
Re: Fluke 123 Scopemeter and battery replacement
« Reply #1 on: March 02, 2013, 03:34:28 pm »
Are you sure they got the thermistor right as well? Often I just do a transplant from the old to the new and it almost always works.
 

Offline Cones

  • Regular Contributor
  • *
  • Posts: 62
  • Country: gb
Re: Fluke 123 Scopemeter and battery replacement
« Reply #2 on: March 02, 2013, 04:07:13 pm »
Hi, yes I remember the values being similar on the thermistors. I will check again after it has finished the 19 refresh cycle it is currently running.

As a further footnote to the old battery I have cycled it on my hobby charger a few times. The first time at a 1 amp charge rate to try and get the cell chemistry started. After 3 cycles at 200mA charge and discharge is now reports just over half its original capacity and will run the scopemeter for 2.5 hours. I might try a few more cycles and see what happens!

NiCd and NiMh are relatively low capacity and old tech compared with the new Lipo or LiIon. But I suspect not of those would still take a charge after nine years!! Progress is not always what it seems.

Mark


 
 

Offline amyk

  • Super Contributor
  • ***
  • Posts: 6903
Re: Fluke 123 Scopemeter and battery replacement
« Reply #3 on: March 03, 2013, 02:08:00 pm »
The wrong resistor looks like orange and brown mixup. They do look very similar colours in the photos.

Wrong resistor is grey-red-green-orange brown, 825k +/- 1%
Right resistor should probably be grey-red-green-black brown, 825  +/- 1%
 

Offline jivega

  • Newbie
  • Posts: 2
Re: Fluke 123 Scopemeter and battery replacement
« Reply #4 on: May 28, 2013, 11:59:47 pm »
Hi.
I also recently bought a Fluke 123 with V1.08 firmware without battery. I made a purchase of a Cammeron Sino BP120 NiMh 3000mA, the connector goes both ways, I had to check the manual for how to connect.
The connector also bad wiring in the terminal (Identification). No has resistor identification (0 ohms) to negative. I made the modification and included a 820ohm resistor between Identification cable and negative terminal, but when I do the refresh battery, this indicates 12 hours for NiCd battery not 19 hours. I tried with various resistor values ??but does not work. I dont know if it's the firmware version supports this type of battery.
Cones: What is the firmware version on your Fluke?, thnks.
 

Offline ScubaShan

  • Contributor
  • Posts: 16
Re: Fluke 123 Scopemeter and battery replacement
« Reply #5 on: August 15, 2013, 07:19:47 am »
I think its safe to assume the guys at Cameron Sino are colour blind. Mine arrived with a completely different resistor measuring 3.9Meg Ohm
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #6 on: August 19, 2013, 11:05:06 am »
Hello guys
about fluke 123 and also 124 I done mod let the instrument to charge and use 2x 18650 Li-Ion battery
I have modded 2 units and running  from 6 months still work great no autodischarge like NiMh and run time is very long, the hack consist in:
1 mod charge voltage to 8.4v to charge in safe 2 cells from 3.7v (4.2+4.2)
2 mod max current charge limit to 600-800mA charge more fast
3 add voltage divider between AD multiplexer and MCU to make battery indicator as real possibile
if you interested I will post some pictures and schematics with mods!!
 
« Last Edit: August 19, 2013, 11:44:17 am by rsivan »
 

Offline archaelus

  • Contributor
  • Posts: 11
Re: Fluke 123 Scopemeter and battery replacement
« Reply #7 on: August 20, 2013, 07:36:20 am »
rsivan: I'd be really interested in seeing the modifications you made as I need to get a replacement battery for my 123.

How much battery life do you get out of it now?
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #8 on: August 20, 2013, 12:30:40 pm »
My fluke 124 at 8v input drain 320mA with full backlight and 280mA with dimmed backlight so with 3400mA cells run time should be 8-10h also in stand by drain 1.5-2mA very low you can leave for moths without using and eliminate self-discharge of Ni-Cd Ni-Mh battery!
« Last Edit: August 23, 2013, 03:50:58 pm by rsivan »
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #9 on: August 23, 2013, 02:39:13 pm »
here some more pics
look at battery curve at 5.9v /2 = 2.95v  is good to match the empty battery icon
« Last Edit: August 23, 2013, 03:48:42 pm by rsivan »
 
The following users thanked this post: iurius

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #10 on: August 23, 2013, 02:47:39 pm »
 
The following users thanked this post: iurius, wolfp

Offline ScubaShan

  • Contributor
  • Posts: 16
Re: Fluke 123 Scopemeter and battery replacement
« Reply #11 on: October 07, 2013, 11:01:06 am »
What sort of cells are they?
 

Offline mcleod

  • Contributor
  • Posts: 15
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #12 on: October 07, 2013, 04:36:29 pm »
The horizontal lines on any of the Fluke scopemeters (123/192/192B/ETC) are caused by a failure of the adhesive on the ribbon cable.

I bought a 192 and 192B on ebay earlier this year that both had horizontal lines and was able to get them fixed. After doing a bit of googling on the problem I was able to figure out a way to fix it. If you are interested in repairing yours I can do a short write up, but you would have to give me a day or two to pull one of mine apart to take some pictures.
 

Offline macboy

  • Super Contributor
  • ***
  • Posts: 2021
  • Country: ca
Re: Fluke 123 Scopemeter and battery replacement
« Reply #13 on: October 07, 2013, 04:44:23 pm »
I would have simply put the 825 ? in parallel with the 830 k? one, instead of doing surgery to remove the old resistor. You could have added the parallel resistor anywhere on the cable or even at the connector.
 

Offline ron

  • Regular Contributor
  • *
  • Posts: 87
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #14 on: November 15, 2013, 09:57:44 pm »
The horizontal lines on any of the Fluke scopemeters (123/192/192B/ETC) are caused by a failure of the adhesive on the ribbon cable.

I bought a 192 and 192B on ebay earlier this year that both had horizontal lines and was able to get them fixed. After doing a bit of googling on the problem I was able to figure out a way to fix it. If you are interested in repairing yours I can do a short write up, but you would have to give me a day or two to pull one of mine apart to take some pictures.
I would like very much to see your method.  It's common for these displays to develop this problem.
 

Offline cjones

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #15 on: December 19, 2013, 07:04:20 pm »
Hello,
My work has a fluke 123 that hasn't been turned on in 5 yrs or so. Now it isn't powering on at all. I cut open the shrink on the battery and found two of the cells are completely dead. It will not power up with the battery removed and the power supply is reading 20V instead of 15.

Should this thing work with the battery removed? I'm trying to decide if I should buy a battery, a power supply or both (for now I wouldn't mind leaving it plugged in just for use around the lab). I'd like to troubleshoot it more but it won't be seen as a good use of time right now.

 

Offline ron

  • Regular Contributor
  • *
  • Posts: 87
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #16 on: December 19, 2013, 07:14:15 pm »
the power supply is reading 20V instead of 15.

I just checked 2 chargers and they read ~21V without load.
 

Offline cjones

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #17 on: December 19, 2013, 07:22:39 pm »
Thanks for checking that. Do you know if these will run from wall power with the battery removed?
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #18 on: December 19, 2013, 07:46:31 pm »
yes without battery have to work 100%
also if battery very discharged or like shorted when press on must only make a flash and one beep and after off
 

Offline cjones

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #19 on: December 20, 2013, 01:20:23 pm »
Good to know. Thanks rsivan and ron.
 

Offline klim

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #20 on: September 12, 2014, 09:43:37 pm »
Hi i'm interested in the 18650 Battery battery mod for Fluke 123. Is there not a problem to drive the Fluke 123 with 150% (7,4V instead of 4,2V) of it's specified voltage battery level?

This is the original battery pack pinout.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

How do you have connected the identification resistor und NTC in your 18650 battery pack?
 

Offline klim

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #21 on: September 20, 2014, 12:14:37 pm »
One more question: have you used cells with protection board (built in cell / external pcb)?
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #22 on: September 22, 2014, 03:59:15 pm »
Hi i'm interested in the 18650 Battery battery mod for Fluke 123. Is there not a problem to drive the Fluke 123 with 150% (7,4V instead of 4,2V) of it's specified voltage battery level?

This is the original battery pack pinout.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

How do you have connected the identification resistor und NTC in your 18650 battery pack?
yes I've used normal cells but protection board is on battery holder,I leaved resistor on wiring, keeping  NiMh setting,about higher voltage: I done some test,starting from 4,5v to 10-12v and watching at current drain, from 4 to 9-10v current drain going down while increasing voltage,this good because internal LDO in fluke controller doing the right job,after 10-12v start  to rise ,and this not good,but for us running on Li-Ion is perfect because will never go above 8.4v(4.2*2) ,also stand-by current drain is very low like 1-2mA same as original or lower.
« Last Edit: September 22, 2014, 04:03:31 pm by rsivan »
 

Offline klim

  • Contributor
  • Posts: 5
Re: Fluke 123 Scopemeter and battery replacement
« Reply #23 on: September 25, 2014, 07:39:51 pm »
Hi rsivan and thank you very much for your reply.
Now it's time to renew my Fluke 123 with new state of the art li-ion powered energy ;-)
 

Offline melhookv12

  • Newbie
  • Posts: 1
Re: Fluke 123 Scopemeter and battery replacement
« Reply #24 on: February 03, 2015, 04:51:13 pm »

Hi I have also purchased a Cameron Sino battery from e bay. I tried a refresh cycle and had no luck. After using Google I ended up here.

I also think my battery is wired incorrectly but I have no reference to relocate the wires. Can someone confirm the location of pin 1. I have tried to attach a picture and it is with the security tag facing upwards. In the op's it doesn't show a tag on the connector, does this mean its facing downwards or it doesn't have one.

Any help greatly appreciated.
 

Offline wptski

  • Contributor
  • Posts: 7
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #25 on: February 02, 2016, 11:42:04 pm »
This thread is a bit old but my post is on the same topic.

I have a Fluke 120 and maybe it's a bit different.  I have 18650 cells and a PCB type holder coming.  I first tried using a power supply raising the voltage to 8.4V and watch the current decrease just like mentioned above.  I used a harness from a BP120 Ni-CD pack and connected two old 18650's I had which worked fine.  The charging part of the mod "might" be too much for my old soldering skills so keep that in mind.

I had another Ni-CD pack still wired up so I connected that.  Connect the OEM power supply at it charged at 400mA.  Now with the 18650's connected, the battery drain increased by almost 100mA.  Either the 120 is different or that's what the charging part of the mod cures.  I'll just use battery power and charge the cells with another charger.

I've been having a guy that builds packs build them for me and I just add the old harness.  Been doing this for a Fluke 199B, 43B and the 120 going back to 2011.

The user that posted this mode hasn't been here since that time so I'm guessing this post won't be answered.
« Last Edit: February 10, 2016, 05:47:56 pm by wptski »
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #26 on: February 10, 2016, 02:47:07 pm »
Hello guys,my fluke still working fine no fire no explosion so mod was ok ;-)
if you look at service manual for scope also search for f199 or f99 you see all circuit, to adjust charge current just hack the 3 shunt resistors ,increasing it will be decrease charge current,
only important things: do not overcharge, so without battery connetcted to  fluke voltage on battery plug must not go over 8,4v.....(this based to li-ion batt 3.7v main rule...)
« Last Edit: April 03, 2017, 09:05:57 pm by rsivan »
 
The following users thanked this post: jellytot

Offline wptski

  • Contributor
  • Posts: 7
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #27 on: February 10, 2016, 05:46:08 pm »
I'm affraid my old soldering skills aren't for surface mounted components.

I received the protected holder(s) and the same 18650 cells that you used for your mod.  Wired my Fluke 120 and working on a Fluke 43B PQ meter which is basically a 120 with different buttons.  Without any internal circuits being modified, cells nearly fully charged, connected to AC power, current still draws from cells.  It appears(monitoring that right now), as cells deplete near 7.3V which is the OEM charging voltage the cells "should" switch to CV mode.  Right now at 7.5V, current is at 140mA down from 300mA>.

Battery only mode for me is okay.  The catch is one either charges the cells while in the holder as a pack removing it every time or remove the cells and charge them however.  The PCB in the holder has to be RESET after cells are removed more than a few seconds.  Plugging in the AC power will RESET the PCB as well.

Seem to bottom out drawing around 40mA from the pack so I halted the test.

EDIT
After several hours the draw on the batteries the current goes to zero so the pack never goes below 7.5V so not that bad really.
« Last Edit: February 12, 2016, 11:46:11 pm by wptski »
 

Offline f11

  • Newbie
  • Posts: 1
  • Country: ro
Re: Fluke 123 Scopemeter and battery replacement
« Reply #28 on: February 27, 2016, 05:40:45 pm »
@rsivan , Thank you very much ! My Fluke 123 is powered by Li-Ion battery.
 
 f11
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #29 on: April 01, 2016, 11:17:22 pm »
Hi folks!

I am in the same boat as you. Dead batteries and no power on even after long charge. Device is BNIB, but 5 years old :-BROKE

What is the name of cells used in BP130 battery (OEM one for Fluke 124)?

Sub C (23x43 mm)? 4/5 Sub C (23x34 mm)? Or something else?

Thanks & have a nice weekend!
« Last Edit: April 02, 2016, 11:42:34 am by EIKA »
 

Offline mojoe

  • Frequent Contributor
  • **
  • Posts: 266
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #30 on: April 02, 2016, 04:56:10 am »
I took my dead battery pack to a Batteries Plus store to have it rebuilt. It only costs me $12. If you have something similar in your country, I would take it there.
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #31 on: April 02, 2016, 09:15:24 am »
I took my dead battery pack to a Batteries Plus store to have it rebuilt. It only costs me $12. If you have something similar in your country, I would take it there.

I can do it by myself. Why not?
 

Offline wptski

  • Contributor
  • Posts: 7
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #32 on: April 02, 2016, 11:35:07 am »
They are SUB C cells.
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #33 on: April 02, 2016, 11:38:20 am »
Yes. Just measured them. 22.4 mm diameter and 42.5 mm height w/o + tip. With tip it might be ~43 mm. So, it's usual SUB C  :-/O
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #34 on: April 24, 2016, 06:08:38 pm »
Hi all!

I've bought the BP130 battery off eBay http://www.ebay.com/itm/161759037081, from cellephone-express seller based in Germany.

It's aftermarket one, I know. And after I got it I immediately found out that It’s 4 wires only, but not 5 as OEM one.

And all looks like it can't be charged when installed into Fluke 124. Nothing changes after 20 hours plugged to PSU. No charging process, no battery warming, etc. it was flat and it's now flat. Battery refresh can't be run - device switches off immediately. Looks like it's cheap Chinese junk / rip-off.

PSU is OEM, device is brand new. Wall socket is 100% working and switched on all the time.

Picture of this battery attached below.

DON'T BUY THIS JUNK!
« Last Edit: April 24, 2016, 07:57:55 pm by EIKA »
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #35 on: April 24, 2016, 07:36:23 pm »
After some time of reviewing both batteries I decided to swap wire harnesses with all components (excluding the thermistor). Installed old harness on fresh cells battery and left the rest stuff on the shelf. As result I got 5th line (additional positive), proper connector with locking tab, and proper ID resistor as well. BTW, old resistor was 3,9 MOhm instead of OEM's 821 Ohm.

Now it takes charge well.

Damned Chinese guys, what the hell they doing? Reported to seller, but I am not sure that it will follow me.
« Last Edit: April 24, 2016, 09:24:11 pm by EIKA »
 

Offline BFX

  • Frequent Contributor
  • **
  • Posts: 368
  • Country: sk
Re: Fluke 123 Scopemeter and battery replacement
« Reply #36 on: April 24, 2016, 09:49:33 pm »
Yes I bought also this battery but I found soon that there is chinese bug as usually :)
For me is only surprise that this product sell german company.
I warned them about it about half a year ago.
 
The following users thanked this post: EIKA

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #37 on: April 24, 2016, 09:55:32 pm »
I think that they will ignore and it's a reason why I already left negative for them.
 
The following users thanked this post: Monittosan

Offline teksturi

  • Regular Contributor
  • *
  • Posts: 59
  • Country: fi
Re: Fluke 123 Scopemeter and battery replacement
« Reply #38 on: April 25, 2016, 02:49:12 pm »
I also buy that same battery pack. Put new resistor and change positive connector to other hole in the connector. When I go to battery refresh page my unit say that battery refreshing take only 12 hours. My unit software version is 01.02.


Edit:
I found a answer from fluke web page http://www.fluke.com/fluke/tten/support/software/ScopeMeter_Firmware_Upgrades.htm
Version 2.02 update notes says:
"Battery refresh time changed from 12 to 19 hours to reflect the real situation (V2.02)"
« Last Edit: April 25, 2016, 03:08:41 pm by teksturi »
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #39 on: April 25, 2016, 06:03:56 pm »
Thanks! Good to know.
« Last Edit: April 25, 2016, 06:29:02 pm by EIKA »
 

Offline EIKA

  • Contributor
  • Posts: 12
  • Country: ru
Re: Fluke 123 Scopemeter and battery replacement
« Reply #40 on: April 25, 2016, 06:05:00 pm »
And small offtotic: what I need to perform FW upgrade? One of extremely expensive Fluke cables? Serial or USB one? Something like $200 for any one...
 

Offline teksturi

  • Regular Contributor
  • *
  • Posts: 59
  • Country: fi
Re: Fluke 123 Scopemeter and battery replacement
« Reply #41 on: April 25, 2016, 06:39:08 pm »
Check this out. http://omapalvelin.homedns.org/fluke/
find CP2102 on that page and you will get your cable  :box: I just started to design my own adapter.
 
The following users thanked this post: EIKA

Offline teksturi

  • Regular Contributor
  • *
  • Posts: 59
  • Country: fi
Re: Fluke 123 Scopemeter and battery replacement
« Reply #42 on: April 26, 2016, 06:03:27 pm »
Just ordered my own version https://oshpark.com/shared_projects/nLb7niLM I will tell how it works.
 

Offline patrickdevos

  • Newbie
  • Posts: 2
  • Country: be
Re: Fluke 123 Scopemeter and battery replacement
« Reply #43 on: June 03, 2016, 07:56:57 am »

Hi I have also purchased a Cameron Sino battery from e bay. I tried a refresh cycle and had no luck. After using Google I ended up here.

I also think my battery is wired incorrectly but I have no reference to relocate the wires. Can someone confirm the location of pin 1. I have tried to attach a picture and it is with the security tag facing upwards. In the op's it doesn't show a tag on the connector, does this mean its facing downwards or it doesn't have one.

Any help greatly appreciated.
Hy
I have same problem. Did you solved it? Can you post photo with correct wiring. Where is 1 on the plug. Maybe the colours on the plug photo
Thank you




Verzonden vanaf mijn iPhone met Tapatalk
 

Offline patrickdevos

  • Newbie
  • Posts: 2
  • Country: be
Re: Fluke 123 Scopemeter and battery replacement
« Reply #44 on: June 03, 2016, 05:54:53 pm »
Hi,

I bought a cheap Fluke 123 scopemeter from ebay with lines on the screen and a flat battery. No problem I thought, I can live with the lines and I will just get a new 3rd party battery for £15 from Amazon here in the UK.

This is where all the fun and games starts!

The original Fluke battery is a BP120 and is a 2000mAh NiCd unit. It would not charge in the scopemeter and would only maintain the unit for 30 second or so before it powered down.

The new replacement battery is made by Cameron Sino and is a BP130 Equivalent 3000mAh NiMh unit.

But on comparing the wiring on the 6 pin connector for the two batteries the new 3000mAh one is wired wrong and will not work at all in the scopemeter. As it was low cost and not worth the hassle of changing it. I have investigated further and resolved all of the problems with it.

This is the correct pin wiring for the scopemeter battery connector.

Pin 1 Not Connected
Pin 2 +
Pin 3 -
Pin 4 I Identification (0 Ohms=NiCd) (825 Ohms=NiMh) Return on Pin 3
Pin 5 Not Connected
Pin 6 T Temperature Sensor (NTC Resistor) Return on Pin 3

So I swapped the connector pins round in the plug on the new battery and then the meter would power on with it. But it still would not charge fully or perform a battery refresh operation.

After a bit of Googling and a look at the Fluke service manual I found the above pinout information and I also discovered the correct resistance value for the NiMh battery.

I measured the value on my battery Identification resistor and I got a resistance of 0.8301 Meg Ohms not the 825 Ohms it is supposed to be. So the manufacturer not only wired the plug wrong they also compounded the problem by putting the wrong resistance value in as well!

So I have now cut open the heat shrink and corrected their mistakes as you can see in the pictures below.

Battery


Original and pending replacement resistor


Crap insulation on the opposite side of the original resistor


Removed resistance value


Replacement Resistance Value


Correct Plug wiring


Repaired and heatshrink added for a slightly better insulation


Red insulation tape as I have run out of larger heatshrink. This may get replaced in future if I can be bothered!


Original Battery pack


Refresh now detects the NiMh and changes from 12 (NiCd) to 19 Hours! Result.





Hello
Please could you show with photo pin layouts? Or photo so to see clear all wired coulours in plug
I dont have original batt to compare wired on plug
Thanx



Verzonden vanaf mijn iPhone met Tapatalk
 

Offline Barniboy

  • Newbie
  • Posts: 2
  • Country: dk
Re: Fluke 123 Scopemeter and battery replacement
« Reply #45 on: August 16, 2016, 09:28:37 am »
Dear "Cones"
Like "patrickdevos" I also feel some confusion about the actual pinout numbers for the connector plug itself.
Could it be as per attached (as seen from the rear, i.e. where the wires come out) ?
From your picture "correct Plug wiring" it seems that only the top black wire (terminal 4 if I am correct in the attached sketch) goes definitely to the identifying resistor.
The white wire (terminal 2 if I am right in the attached sketch) seems to go the NTC resistor, hidden in the shrinked tube, I think. But this should go to batt. plus directly ?
The other black wire, and the red can not be determined from your photo.

Is it possible for you to clarify the actual connector pinout ?
 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #46 on: August 17, 2016, 07:21:01 am »
Dear "Cones"...
Is it possible for you to clarify the actual connector pinout ?
Is this the battery side or instrument side connector?



(PS:
Correction (see my next posting): This is the battery side connector view from the "holes" side, not from the "wires" side, as you wrote)
« Last Edit: August 17, 2016, 06:58:48 pm by carl_lab »
 

Offline Barniboy

  • Newbie
  • Posts: 2
  • Country: dk
Re: Fluke 123 Scopemeter and battery replacement
« Reply #47 on: August 17, 2016, 08:19:06 am »
Hello Carl_lab
First, please note that my attached sketch is my question, not my statement.
My reply to your question: As the sketch indicates in text, it is a question regarding battery connector pinout, as seen from the rear of the connector where the wires come out.
Have I got his numbering right, with respect to the numbering in the Fluke Service Manual ?
Again: The Fluke SM schematic is very clear on terminal connector numbering, but no clue is given as to what numbering the corresponding terminal pinout on the instrument PCB are, nor the battery connector receptacle.
This is probably the reason why almost every aftermarket replacement battery is wired wrong, according to many posts in internet media.
 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #48 on: August 17, 2016, 06:28:40 pm »
Hi Barniboy,
I did not open my battery yet, but if I look at this photo, I'm pretty sure the red wire is battery+.
The next (thinner black) wire in the middle of the upper row is connected to the "ident resistor".
The white wire seem to be connected to the NTC.
The last wire (black) must be battery- and goes to the middle position on the lower row of the connector.


 (c) Cones

So your sketch seems to be correct, but mirrored battery connector side (or in other words: your sketch shows the connector from instrument side correctly).

You can compare with your original battery connector!
« Last Edit: August 18, 2016, 06:10:52 am by carl_lab »
 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #49 on: August 18, 2016, 06:16:53 am »
Has anybody tried a single LiIon cell (3.0-4.2V)?

At which battery voltage does the low battery indicator appear and when will the scopemeter shut down?
« Last Edit: August 18, 2016, 06:50:05 am by carl_lab »
 

Offline Dbldutch

  • Regular Contributor
  • *
  • Posts: 160
  • Country: nl
Re: Fluke 123 Scopemeter and battery replacement
« Reply #50 on: November 06, 2016, 05:00:19 pm »
Be aware of the Cameron Sino battery packs.

I have one, the CS-FBP120SL, and it simply does not work in my 123. It comes with the yellow NTC lead connected to a normally unused pin (1 or 5) on the connector and that is the only position the scope will boot. If you connect the NTC lead to the proper pin 6, the boot procedure is terminated, and the scope will not work, not even with the wall wart connected.

You can identify this battery pack by the lack of the second black wire, instead, there is a yellow one, which is used for the NTC connection. Although it says on the battery pack that it uses NiMH cells, there is no resistor in the identification link, so the scope treats it as a NiCAD pack. The bad part is that with the NTC lead going to an unused pin, the scope will not charge this pack. I have modded the pack and added the 825 Ohm resistor, but without success.

If you have a working pack, better yet an original one, can you please measure the NTC resistance at room temperature, or identify the partnumber?


I just ordered another pack, from another supplier, and from the picture, it seems to have the proper wiring.
 

Offline Dbldutch

  • Regular Contributor
  • *
  • Posts: 160
  • Country: nl
Re: Fluke 123 Scopemeter and battery replacement
« Reply #51 on: November 08, 2016, 07:45:53 pm »
I have a follow-up on my previous post.

After looking long and hard to find a pack that was not coming from the apparently unreliable Cameron Sino stables, I found one that I ordered from 123accu.nl in the Netherlands.

From the pictures, it was clearly not coming from CS, and judging from what I could see of the connector, it had two black wires, so I ordered it. It just arrived, so I quickly got my DMM switched on and measured the resistance of the NTC and the ID wires against ground. The ID showed the presence of the 825 resistor, and the NTC showed about 12K (the pack was still cold from the transport). The voltage was about 5.1V, so I smelled success.

Although the connector had another (red) wire going to the unused pin 5, I installed it in my 123, and it switched on perfectly with only the battery connected.

Unfortunately, there is no manufacturing information on the pack, only a part number : B11483
It is a NiMH pack, with 4.8V, 3000mAh/14.4Wh, just as it supposed to be.

In the box I even found two black foam strips to replace the two already in the 123, which is a nice touch.
On the 123accu.nl provided box, it clearly states this is a Fluke BP120MH / B11483 / BP120 accu.
Of course these 123's are made in the Netherlands, but in any case, they have the right product.

The version number of my 123 readws V01.08, and is from 2000.
This also means that the refresh rate is still showing 12 hours, but at least is recognizes the pack as a valid one.

Now I need to build me an optical cable and see if I can update the firmware to the latest version that my hardware version will support.

I'm happy, and I hope you can use this information to get your 123 up-and-running as well.



 
The following users thanked this post: BillyD

Offline umkumiut

  • Contributor
  • Posts: 17
Re: Fluke 123 Scopemeter and battery replacement
« Reply #52 on: November 11, 2016, 01:45:15 pm »
Now I need to build me an optical cable and see if I can update the firmware to the latest version that my hardware version will support.

From Fluke's website: "Instruments with firmware version V1.0x cannot be upgraded to V2.03"
V1.08 is the latest from the 1.xx family, so there is no further update.
The foam strips are indeed a nice addition, mines already started to decompose (my instrument is from 1998)...

http://en-us.fluke.com/support/software-downloads/fluke-scopemeter-123-124-series-version-2-firmware-upgrade.html

 

Offline Dbldutch

  • Regular Contributor
  • *
  • Posts: 160
  • Country: nl
Re: Fluke 123 Scopemeter and battery replacement
« Reply #53 on: November 23, 2016, 07:16:10 am »
Hi Umkumiut,

1998?, you must have one of the earliest models!
My version is already at V01.08, so no chance to update the firmware, thanks for the hint.
I am building an optical interface anyway to connect the 123 to a computer and get access to the data.

Regards,

Paul

 

Offline abid0011

  • Contributor
  • Posts: 12
  • Country: ae
Re: Fluke 123 Scopemeter and battery replacement
« Reply #54 on: April 03, 2017, 06:36:26 am »

 i buy individual battery cells each cell is 4000mah 1.2v
 the battery pack with the fluke 123 is 2000mah.
 
when open the original battery pack i remove the top covered pvc to copy the wiring connection i saw some two thing connected.

can i remove  the old wiring and solder to the new battery cells as on the fluke battery pack.

need suggestion .

thank u
 

Offline mucek

  • Contributor
  • Posts: 35
  • Country: si
    • eCAT electronic engineering
Re: Fluke 123 Scopemeter and battery replacement
« Reply #55 on: April 03, 2017, 08:11:00 am »
Here's my mod for LiIon battery (based on info in this forum) as well as replacing CCFL lamp with LED backlight. The difference is enormous! Now F123 is easily readable in every condition! :) There is plenty of images with description ...

http://iksor.si/en/2017/04/03/fluke-123-modifikacija-na-liion-in-led-osvetlitev/

Regards,
Gregor

p.s. We are still working on our webpage, especially english one is pretty "lonely" ... Don't look too much around ;)
« Last Edit: April 03, 2017, 08:13:07 am by mucek »
 

Offline abid0011

  • Contributor
  • Posts: 12
  • Country: ae
Re: Fluke 123 Scopemeter and battery replacement
« Reply #56 on: April 03, 2017, 09:15:53 am »
thanks for reply.

as u say this unit is pretty old.
what do u think fluke 123 vs the fluke 87v or 88v multimeters.

does the fluke 123 better than these two millimeters

thank u
 

Offline mucek

  • Contributor
  • Posts: 35
  • Country: si
    • eCAT electronic engineering
Re: Fluke 123 Scopemeter and battery replacement
« Reply #57 on: April 03, 2017, 06:53:59 pm »
You can't compare those two! F123 is Scopemeter, which is an oscilloscope and digital multimeter in one unit, when 87 (and similar) are "only" multimeters. I do owe also F279 and I try to avoid it, as it takes quite some time to startup. I use F179 instead usually.

Regards,
Gregor
 

Offline rsivan

  • Contributor
  • Posts: 42
  • Country: it
Re: Fluke 123 Scopemeter and battery replacement
« Reply #58 on: April 03, 2017, 09:28:43 pm »
Here's my mod for LiIon battery (based on info in this forum) as well as replacing CCFL lamp with LED backlight. The difference is enormous! Now F123 is easily readable in every condition! :) There is plenty of images with description ...

http://iksor.si/en/2017/04/03/fluke-123-modifikacija-na-liion-in-led-osvetlitev/

Regards,
Gregor

p.s. We are still working on our webpage, especially english one is pretty "lonely" ... Don't look too much around ;)

very interested the led mod!... also  :-+ for nice schematic with my mod,unfortunately cannot try led mod because selled my F123 6 months ago to a friend which very happy with,
I got a discount from supplier for F125B (colors model) and I could not resist....I'm very happy with, this time no need hack (for now), battery life is good and already li-ion
« Last Edit: April 03, 2017, 09:33:57 pm by rsivan »
 
The following users thanked this post: abid0011

Offline abid0011

  • Contributor
  • Posts: 12
  • Country: ae
Re: Fluke 123 Scopemeter and battery replacement
« Reply #59 on: April 07, 2017, 07:38:00 am »
hi i replace the fluke 2000 mah with the 4000 mah battery.
what i did is i remove the wired connection from the original battery pack and installed on the 4000 mah 1.2 volts 4 cells.

now the problem is after charging the battery the battery drains very quickly.
does the battery need completer refresh .
when select the refresh option it shows 12 hours.

any suggestion.

thank u
« Last Edit: April 07, 2017, 07:40:23 am by abid0011 »
 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #60 on: April 09, 2017, 08:16:48 am »
Is your 4000mAh battery NiMH type? NiMH has a significant self discharge.

Which time does it take to completely self discharge?
 

Offline abid0011

  • Contributor
  • Posts: 12
  • Country: ae
Re: Fluke 123 Scopemeter and battery replacement
« Reply #61 on: April 09, 2017, 11:25:52 am »
suppose I put the scope for charge 5 hours.

yes the battery type is 4000 mah Nimh
when I power on the scope the battery will discharge with in 30min and the x sign shows on the batter icon.

 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #62 on: April 10, 2017, 07:48:20 pm »
I don't know, if there's a timeout limit for charging time, or not, but if it is, your batteries will not full charged.
5 hours charging at 400mA will charge your battery only 2000mAh (or 50% of 4000mAh).

Here's a link to mod charge current from 400mA to 800mA to overcome possible timeout limit:
http://iksor.si/en/2017/04/03/fluke-123-modifikacija-na-liion-in-led-osvetlitev/

Can you charge your battery externally from a laboratory power supply, RC charger or similar to 8,4V?
Then test operating time of your scope to shut down.
« Last Edit: April 10, 2017, 08:25:05 pm by carl_lab »
 

Offline abid0011

  • Contributor
  • Posts: 12
  • Country: ae
Re: Fluke 123 Scopemeter and battery replacement
« Reply #63 on: April 11, 2017, 11:37:29 am »
thank u for reply.

need one suggestion.
i am a electrician and now i start learning electronics as hobbyist.

fluke 123 is a scope meter dual multi meter with scope.

the fluke have black line on display and also facing problem with the battery.

i am thinking to sell this unit or keep it in my storage. and buy a fluke 28-2 or 87 - v multi meters.

question is  that fluke 123 worth to spend time to make it perfect and what u think as we know its old unit still better in  functionality then the above mentioned meters.


thank u


 

Offline carl_lab

  • Frequent Contributor
  • **
  • Posts: 418
  • Country: de
Re: Fluke 123 Scopemeter and battery replacement
« Reply #64 on: April 11, 2017, 04:52:25 pm »
Fluke 123 (or 99) is a scopemeter, not only a simple multimeter as the others you mentioned.
It is a portable, isolated (!) oscilloscope, that also can be used as a multimeter.
A multimeter only is useless if you have to watch waveforms.

Keep the scopemeter and buy an additional multimeter, if you need more accuracy or functions as continuity beeper, capacitance, temperature etc.

PS: additional static lines on LCD is probably a contact problem between PCB and LCD. Can you show a photo?
« Last Edit: April 12, 2017, 06:26:32 am by carl_lab »
 

Offline none

  • Contributor
  • Posts: 18
  • Country: 00
Re: Fluke 123 Scopemeter and battery replacement
« Reply #65 on: June 18, 2017, 09:17:25 am »
I have an 123 on FW 1.08 (earlier model, late nineties, 20 yrs old!) and rebuilt the battery pack with Sanyo NiCd batteries (KR-1800SCE) once, but that did not last very long and I have since been running the scope on power adapter only. I'm digging this up because I've always been interested in fixing this, and now I need to be able to use the scope on batteries. This will either be a DIY NiMH pack or maybe even Lithium. I'll try to recap and add more info in the hope it may help others.

There used to be a forum/discussion on http://www.flukecommunity.com/forums/showpost.php?p=6844 "123 battery pack, difference BP120 <-> BP120MH?" with some information on the battery pack by someone looking for the NiMH ID resistor. They seem to mix up their links regularly, the new forums are now called "Fluke Nation" and seem to be outsourced to http://flukecorp-cx.custhelp.com/app/utils/login_form - however, this now seems to be inaccessible without registration/login. The thread now is at http://flukenation.com/posts/9d37b58388. Another, more recent one, "BP130 battery" at http://flukenation.com/posts/32b879babc.

Back to the charging:

The charging circuit and procedure are very well described in the ScopeMeter Service Manual. There are a few different versions of the manual, but the power/charging section overview seems to be mostly identical. The 2003 version has added information about the battery packs and ID resistors:

Quote
Two different battery packs are possible: as a standard Fluke 123 is equipped with a Ni-
Cd battery, Fluke 124 has a Ni-MH battery that allows a longer operation time. Both
instruments will also function on a battery pack different from the standard type. The
installed battery type is read by the D-ASIC via BATIDENT/BATIDGAR (pin B5): for
Ni-Cd there is 0 ? between BATIDENT and – of battery, for Ni-MH this is 825 ?.

Battery pack models:
BP120 - original NiCd -obsolete-
BP130 - Battery Pack NiMH for ScopeMeter 124 -obsolete-
BP120MH - NiMH Battery Park for Fluke 123, Fluke 43 and 43B - The BP120MH replaces the earlier models BP120 and BP130 alike. SKU 2544081: $129.99 (https://www.flukeonlinestore.com/products/batteries-and-chargers/battery/bp120mh-rechargeable-battery-pack-for-43-43b-123)

No mention of the 123 V1 with last FW 1.08 supporting/using the NiMh ID-resistor so far.

Firmware Upgrades
http://www.fluke.com/fluke/uyes/support/software/ScopeMeter_Firmware_Upgrades.htm
http://en-us.fluke.com/support/software-downloads/fluke-scopeMeter-123-series-version-1-firmware-upgrade.html

V1.08 changes do not mention battery support, I can't find changelogs for earlier firmwares.

How the charging works (see service manual):

Nominal battery voltage: 4*1.2 V = 4.8 V ("If no battery pack is installed, VBAT is approximately +15V.")

The power/charge supply is a 100 kHz switch mode regulator in the P(ower)-ASIC, which in turn is controlled by D(igital)-ASIC.
Charge conditions/cycle:
  • Battery Voltage (VBAT, via BATVOLT) <5.2V (is this a typo and it should be 4.2 V?), Battery temperature 10..45 °C
  • 500 mA until dV/dt, up to 6 h (fast charge)
  • 200 mA 2 h (top off)
  • 60 mA trickle up to 48 h

The lower limit seems to be 4.0 V, the instrument then enters OFF mode (see "3.2.5 Start-up Sequence, Operating Modes").

Safety measures:
  • both ASICs monitor temperature, bimetal switch shuts off at 70°C.
  • "The P-ASIC limits the voltage VBAT to 7.4V via its internal Control circuit.  This situation arises in case no battery or a defective battery (open) is present." This voltage is probably set by R513 / VBTHIGH.


Thoughts on the Lithium battery hack

Regarding user rsivan's mod starting at https://www.eevblog.com/forum/testgear/fluke-123-scopemeter-and-battery-replacement/msg279033/#msg279033
They modified VBTHIGH to 8.2 V, doubled the charging current by halving IBAT sense shunt resistor, and modifying the voltage feedback BATVOLT.

Lithium batteries are charged constant current followed by constant voltage, determined by absolute cell voltage:
https://www.digikey.com/en/articles/techzone/2016/sep/a-designer-guide-fast-lithium-ion-battery-charging

Without modifications, a single lithium battery cell (3 ... 4.2 V) would be overcharged, but 2 in series might not have that problem, as the charger hardware supposedly limits the voltage to 7.4 V (just about the nominal 2*3.7 V, so quite a lot of headroom, but not using the full battery capacity [by far]).
However, they would be discharged down to 4 V (2V)!

Can the lower level be modified, too?
 
User rsivan has determined threshold levels for the battery voltage with regard to battery indicator and shutdown, though the theory does not seem to match their value:
  0.95 V for battery X icon ((0.95/0.67)+3.27 = 4.687)
  0.8 V for shutdown threshold ((0.80/0.67)+3.27 = 4.464)

rsivan gives 5.9V for their battery warning threshold, so (5.9-3.27)*0.67 = 1,7621.

The calculation is derived from service manual section "7.5.3 Slow ADC"
"BATVOLT (N501 pin 78), must be {0.67 x (VBAT-3.27)} Volt.", (Measure VBAT on TP504 = N501 pin 3), so:
  (7.4-3.27)*0.67 = 2.7671
  (4.8-3.27)*0.67 = 1.0251
  (4.0-3.27)*0.67 = 0.4891

Something is off!

Regardless of the 4V shutoff treshold, the  +3V3GAR linear regulator is always on, draining the battery (slowly). Assuming a 0.65V V drop by the transistor, we're also at just below 4 Volts minimum (there still might be current drawn by the regulator and/or other parts that are constantly connected).

So for lithium batteries it seems one would need to rely on the charger's overvoltage cutoff (instead of dV/dt), but also on the batteries protection circuit's shut-down function to disconnect the battery at undervoltage, though I don't know how the charger circuit reacts to that and how the protection circuit would "recover":
  Overvoltage -> Battery protection disconnects -> Vbat rises to 15 Volts (?) as power control assumes there is no battery
  Undervoltage -> same if battery appears to be disconnected.

Any input on this appreciated.

The battery types on Wikipedia :
https://en.wikipedia.org/wiki/Nickel%E2%80%93cadmium_battery
https://en.wikipedia.org/wiki/Nickel%E2%80%93metal_hydride_battery
https://en.wikipedia.org/wiki/Lithium-ion_battery
 

Offline gowniak13

  • Newbie
  • Posts: 2
  • Country: gb
Re: Fluke 123 Scopemeter and battery replacement
« Reply #66 on: August 01, 2017, 10:45:44 pm »
i will keep updating this post from time to time.

I just purchased old fluke 123 with original ni-cd batteries in.. and im looking to upgrade them, monitoring this thread, any update or progress for ultimate solution Mr. noone ?

my 123 has 1.04 software... upgrading to 1.08 wont change anything, anyway;

from my research for now the best Ni-Cd cells to use are; Sanyo n-3000cr, i havent seen Ni-MH yet but i still dont understand some things, like for example charging circuit inside the scopemeter, i have already read some post saying that putting Ni-MH cells inside f123 are not doing the job, is that because f123 is not designed to use Ni-MH cells ? i mean 'using' as also process of recharging them inside scopemeter, charging current between Ni-Cd and Ni-MH should be different, right ?, yes i know, i will read service manual later on..., the problem is that i dont want to modify pcb yet cause it doesnt seems to be stable enough for a long run(?).

Quote
No mention of the 123 V1 with last FW 1.08 supporting/using the NiMh ID-resistor so far.

« Last Edit: August 01, 2017, 11:56:19 pm by gowniak13 »
 

Offline Dr. Ka

  • Newbie
  • Posts: 1
  • Country: at
Re: Fluke 123 Scopemeter and battery replacement
« Reply #67 on: April 03, 2019, 12:49:20 pm »
Not sure if this still interests somebody. Nevertheless, I have just completed the LiIon-Mod. It had a NiCd battery before that was empty, whenever I needed it...

Here are my thoughts: 

Charging

User none has mentioned the charging process:
Quote
500 mA until dV/dt, up to 6 h (fast charge)
200 mA 2 h (top off)
60 mA trickle up to 48 h

A LiIon battery does not show a dV/dt dip, therefore the charging process reduces to constant current charging for up to 6h (with a limited maximum voltage).

I have measured the charging current, in my device it is 480mA. My LiIon cells should be fully charged within 6 hours, but I wanted to reduce charging time...
As user rsivan suggests, I have added 3x1R  resistors (1206 SMD) in parallel to R504/R506/R507 to double the charging current.


Quote
"If no battery pack is installed, VBAT is approximately +15V."

I read that too in the manual, but elsewhere it says: "The P-ASIC limits the voltage VBAT to 7.4V via its internal Control circuit. This situation arises in case no battery or a defective battery (open) is
present."  The measured value in my device was 7.58V. This is the highest voltage, the charger provides to the circuit and battery (independent if battery is installed or not). In no case, the Vbat voltage rises to 15V!

As user rsivan suggests, the value can be modified by altering the value of R513. I desoldered the original 26.1k resistor and replaced it with a 28.7k one (0805 SMD). In my case the charging voltage (VBAT) is now limited to 8.3V.

I use 2 LiIon cells. with these two modifications, I have constant current charging (960mA), but the charger limits the battery voltage to 8.3V (4.15V per Cell). Should be OK for my Lithium cells! In case something happens, I still have the battery protection circuit to prevent overcharging.


Discharging

The P-ASIC converts the battery voltage into the signal BATVOLT, which is digitized by the SlowADC. The conversion is given in the manual (as user none mentioned): BATVOLT= 0.67 x (VBAT-3.27)

After some experiments, I discovered the following behavior with my device:
  • If the battery voltage drops below 4.54V (BATVOLT 0.85V), the battery empty symbol (x) appears in the display.
  • If the battery voltage drops below 4.00V (BATVOLT 0.49), the device can be switched on (display goes on), but immediately powers-down again.
  • If the battery voltage drops below 3.10V, the device cannot be switched on.
The observed values are different from the values stated by user rsivan, but my observations seem reasonable. For the original 4Cell NiCd battery-pack, battery low is displayed at cell voltage 1.135V and and the device is powered down at cell voltage 1.0V.

User none states:
Quote
Regardless of the 4V shutoff treshold, the  +3V3GAR linear regulator is always on, draining the battery (slowly). Assuming a 0.65V V drop by the transistor, we're also at just below 4 Volts minimum.
The linear regulator is a low-dropout regulator, and does not need much voltage overhead! That's why my observations show the 3.10V limit, below which the device cannot be switched on. But the general observation is correct, it is slowly draining the battery. That  is probably the reason why my NiCd batteriy is always empty...

As suggested by user rsivan, I added a voltage divider to the BATVOLT signal path, to adapt the voltage limits. The output impedance of the P-ASIC was measured with about 15kOhm. I thus used a 100kOhm to 68kOhm divider to modify the voltage seen by the slow ADC. The measured voltage is thereby scaled by a factor 68/(68+100+15). With this modification, the battery low signal is now displayed at about 6.66V and the device is powered off at about 5.24V. I have a 2 cell LiIon configuration, the device is thus switched off at a cell voltage of 2.62V.

However, the +3V3GAR linear regulator keeps draining the battery with some mA... In this case I rely on the battery protection circuit, which disconnects the battery if a cell voltage drops below 2.5V. From this time on, the battery protection circuit only allows charging of the cells, but no further discharging.

When the charger is connected, it starts charging the LiIon pack with a maximum voltage of 8.3V. When the cell voltages of my battery pack reach 3V, the battery protection circuit returns to normal operation (charging and discharging allowed).


Until now, my modifications seem to work as expected!



 
The following users thanked this post: none

Offline DMM123

  • Contributor
  • Posts: 5
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #68 on: May 10, 2019, 12:41:39 am »
Guys, I've been trying to get the thermistor part number and the part number for the "fuse" for the BP120 battery pack (NiCad).  Not able to find the part numbers or the values listed in the Fluke service manual.

Anyone know the value of the thermistor or the "fuse"?

I am building a NiCad pack for my 123 and have no info to work with.  Any help appreciated - thanks!

 

Offline none

  • Contributor
  • Posts: 18
  • Country: 00
Re: Fluke 123 Scopemeter and battery replacement
« Reply #69 on: May 19, 2019, 08:55:43 am »
@ Dr. Ka
Yes, thanks for sharing. I have two LIS1441 in the SM123 and just dug out this thread to see what I did last time around. I have a 2S balancer/protection board (https://github.com/megasaturnv/HX-2S-JH20-JH10-reverse-engineered_aka-2S-10A-Balance-Li-ion-Protection-PCB/) that I want to add, since last time I noticed the batteries becoming unbalanced. I'll have to see how this works out, since the batteries appear to have an integrated protection already.
I have currently not planned to modify the ScopeMeter, at the cost of wasting battery capacity and slow charging, of course.

@ DMM123
I think the information about thermistor and fuse is somewhere in this thread, or on the Fluke forums (try the links I posted previously) - I've seen it before.

EDIT:
These threads might be of interest:
https://www.eevblog.com/forum/testgear/usb-powered-fluke-123/
https://www.eevblog.com/forum/testgear/fluke-123/ (power supply)
« Last Edit: May 19, 2019, 09:02:11 am by none »
 

Offline DMM123

  • Contributor
  • Posts: 5
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #70 on: May 19, 2019, 01:11:32 pm »

@ DMM123
I think the information about thermistor and fuse is somewhere in this thread, or on the Fluke forums (try the links I posted previously) - I've seen it before.

EDIT:
These threads might be of interest:
https://www.eevblog.com/forum/testgear/usb-powered-fluke-123/
https://www.eevblog.com/forum/testgear/fluke-123/ (power supply)

Thank you, but I still don't see the thermistor value (beta), the part number, or the range of the thermistor in temperature.  I have contacted a thermistor manufacturer and given them 40 measured values at different temperatures with the kOhm readings on the old battery.  I will post what they say.
« Last Edit: May 19, 2019, 01:18:33 pm by DMM123 »
 

Offline Jcm05

  • Newbie
  • Posts: 1
  • Country: fr
Re: Fluke 123 Scopemeter and battery replacement
« Reply #71 on: June 01, 2019, 10:52:35 am »
Hello,

My Scopemeter does not work after battery exchange.
After seeing verified I found a polarity reversal of + and - on the battery.

This has caused a short internal circuit to my scopemeter and it does not work even connected to the power supply.
The 3 resistors R504, R506 and R507 have burned.
I replaced them but he still does not work.

Have you ever encountered the same problem and what is the solution?

Thanks for your help.
 

Offline DMM123

  • Contributor
  • Posts: 5
  • Country: us
Re: Fluke 123 Scopemeter and battery replacement
« Reply #72 on: July 01, 2019, 12:05:23 pm »

@ DMM123
I think the information about thermistor and fuse is somewhere in this thread, or on the Fluke forums (try the links I posted previously) - I've seen it before.

EDIT:
These threads might be of interest:
https://www.eevblog.com/forum/testgear/usb-powered-fluke-123/
https://www.eevblog.com/forum/testgear/fluke-123/ (power supply)

Thank you, but I still don't see the thermistor value (beta), the part number, or the range of the thermistor in temperature.  I have contacted a thermistor manufacturer and given them 40 measured values at different temperatures with the kOhm readings on the old battery.  I will post what they say.

Well, so far no answer.  I've emailed a couple of times but no response.  Initially they said they would have an answer in a couple of weeks.  Patience, I hope, is the key.
 

Offline iurius

  • Newbie
  • Posts: 3
Re: Fluke 123 Scopemeter and battery replacement
« Reply #73 on: September 19, 2019, 09:04:28 pm »
Thank you very very much!
 

Offline alwanuel

  • Newbie
  • Posts: 1
  • Country: gb
Re: Fluke 123 Scopemeter and battery replacement
« Reply #74 on: May 10, 2020, 01:04:03 pm »
Hi, would you please consider a YouTube video, what you did is really useful, please consider to share it properly. Cheers.
 

Online Flukav

  • Contributor
  • Posts: 21
  • Country: fr
Re: Fluke 123 Scopemeter and battery replacement
« Reply #75 on: October 18, 2020, 08:30:09 am »
Dear experts,
Following the battery & backlight update schematics posted on page number 2, I emailed IKSOR.si, as original pictures were not available anymore. One may find a repository here https://www.dropbox.com/sh/f72c2dpbbcg73bx/AABx5-jHr30Isnmg9G7eDMcXa?dl=0.
So far I upgraded my unit with a LED strip, as the 20yo CCFL tube was dead. The boost converter used, a cheap eBay MT3608 module, switching at 1.2 MHz, is hooked on C561, the 150uF 5VCC supply. It generates a 12VDC feeding 3x3 SMD LED located in the original tube holder. Light is evenly spread across the screen, way brighter than before.
Upon disconnection of the CCFL,  a strong yet clean 614.5Hz shows up whenever bare leads are connected on input A or B.
I of course disconnected the boost module, the DC supply, but the very same noise appear. Connection of a 1MO resistor on the HV pins doesn't help.
Any help will be appreciated.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf