Old Philips Fluke 97 / 96B (maybe others?)

[joeqsmith]

I have needed a portable scope from time to time.  Even 1MHz would have been fine.   Picked up a couple of these locally complete with all the manuals and probes.   Two different revs, fairly different designs.   

[joeqsmith]

The first one is back together.  Needed a few parts and some cleaning.  Other unit looks like it took some damage from a jolt to the front end.  Knew it when I bought it.  So far one of the clamp diodes was blown along with a cap.  Op-amp and one of the 74HC switches looks bad.  Both ELs are a little weak.   

Here's a 60MHz CW wave and a +1 tone wheel for an engine being simulated on the arb.  Not bad for the age of it and how it was used.

[joeqsmith]

With 1MHz 1.40 volt applied.   DSO shows 14.4 but not using the 10X probe. 
 

[joeqsmith]

Comparing with the BM8869s.  First picture showing AC+DC / AC vs AC / DC.    So the Fluke would be 4.806 AC+DC. It may have the math function for this.  Have not spent a lot of time with the user manual. 

Next picture showing my bench supply set to 50 volts.   

Last showing some of readout functions.   Not too bad.   




 

[joeqsmith]

The 97 has a built-in signal generator of sorts.   The signal comes out on the two banana jacks.   Shown with it set to ramp along with the highly modified UNI-T UT181A.  The 181 can only log at 1Hz max. 

I ordered up some batteries for the 97 and have some parts ordered from Digikey to attempt to repair the second scope.  Basically all that is left now is the signal generator is not working.  The problem with it being so old is TI op-amp is no longer made.   So more substituting.   

[joeqsmith]

The 97 came with the 80T-150U temperature probe.    Here is the probe attached to the Brymen compared with my Mastech and Fluke K type sensor.  It needed to be repaired but seems to be working fine now. 

[Scottjd]

Well,since we both got an old fluke scopemeter about the same time, I figured I would take your suggestion and add to your post. Mine is a 96B series II, 60Mhz scope with multimeter.

I tore mine down tonight. Found a few problems but was easy fixes. Nothing with the  components.

Three out of the four posts that the main board screwed into were broken with the metal nut in case in the plastic. I little glue and all good, maybe dropped one to many times. The old battery leaked, some distilled vinegar and a little scraping and all good.
The power transformer was being held together with one screw and a corner broken off. Not much to it inside. On 26V cap at 2200uf, 4 diodes for the bridge rectifier and the transformer. So some epoxy and it's now tying to set.
The CR2032 battery is dead, I didn't notice any issues when I was playing with it. Maybe it hold the calibration data? But I haven't calibrated it yet, so maybe that's why I didn't notice. I need to buy one, I don't have any good ones currently. So I'll replace it before doing the calibration.
Still need to find the service manual, not sure if the cal is done with software like the auto probe cal feature, or if it has to do with the 8 trim pots on the one board.

I'll add the tear down photos in a later post.
Nothing special, just some cell phone pictures.

It took me a little bit to figure out how to post HiDef photos so every one can enjoy the fine little chips and the writing on the chips. I found out the shared URLs for photobucket and flickr both change the image posted. Now that I have figured it out I will have tear down photos up soon.

For now enjoy the image of the full unit a and everything it came with.

[joeqsmith]

Hey Scott, that was great deal you ended up with!  The two 97's I have look a fair amount different in the main control board.  The actual I/O (where the problem is) is one revision apart.  Visibly I did not see the difference and they appear to interchange.  There is no coin battery on mine.   

The charge packs are different as well.  The one in the video looks similar you yours but marked Philips.  My second one has a separate line cord. 

The second 97 is like yours, in there is no mention of Philips on the rear.  I suspect it was made after they acquired Philips.  It's much newer with the later rev I/O.  The control board does not use the separate keypad.  No jumper wires (there was one on the older unit).  It is also marked "FLUKE 97/AUTO SCOPEMETER" rather than "FLUKE 97 50MHZ SCOPEMETER".

I'm interested in seeing how yours differs.

[Scottjd]

Hey Scott, that was great deal you ended up with!  The two 97's I have look a fair amount different in the main control board.  The actual I/O (where the problem is) is one revision apart.  Visibly I did not see the difference and they appear to interchange.  There is no coin battery on mine.   

The charge packs are different as well.  The one in the video looks similar you yours but marked Philips.  My second one has a separate line cord. 

The second 97 is like yours, in there is no mention of Philips on the rear.  I suspect it was made after they acquired Philips.  It's much newer with the later rev I/O.  The control board does not use the separate keypad.  No jumper wires (there was one on the older unit).  It is also marked "FLUKE 97/AUTO SCOPEMETER" rather than "FLUKE 97 50MHZ SCOPEMETER".

I'm interested in seeing how yours differs.

Im working on posting them now. I also updated my last post with some basic photos.
Mine is also not marked with philips, and its a 96B series II that is a 60Mhz one also marked as a scopemeter.
So even if mine has a lower number then your 97, it seems to be made after yours. Maybe the series II is the updated 96B that was refreshed after your 97's? But I have not looking it up to find out the release date. I do recall one chip had a date code of 1986, but I didnt check all the dates. Mine also had a lot more shielding plates.

Im working on posting the tear down photos now.

[Scottjd]

As promised, these are the tear down photos in the highest resolution I could post them. You can always save the image locally to zoom in closer. They were not great photos taken with my DSLR and on a tri-pod or anything like that. It was a late night, just some extra lighting and my cell phone but you can still see a lot of the detail and components.

You can even see the extra pads on the chips and how it the components are laid out since it was wave soldered. I think this is the second thing I have tore down that is waved soldered. I probably took apart more waved solder things when I was younger and over the years, but I didn't really know what I was looking at. 

I tried my best to post them in order to the tear down, but the truth is I took the pictures as I was putting it back together. So I hope they are in the correct order.

I am happy to say it still works after tearing it down and putting it back together. This means my friend that gave it to me wont be mad also. 

To see the full set on Flicker"
https://flic.kr/s/aHskNgtFM3

[joeqsmith]

Very nice!   Yours appears much newer than what I have.  Looks like it has some help menus built in and the display looks much better than mine. 

I received the parts for the second scope today.  As luck would have it the wall supply died while I was trying to debug it.  Tore that apart and it looks like the connector that plugs into the scope opened up the center pin.       The second supply had the same problem that someone had "fixed".   I need to order up some new connectors.   

Changed out all the protection diodes and with the right ones and it appears there is a fractured joint or trace.  Picture of my scope displaying the signal generator's output.  It seems to be working solid now.  All the waveforms work.  Problem is, I have not found the problem!!       

Making some progress. 

[Scottjd]

Well finding the plug to fit these may be slightly chanlanging because of how deep they seat into the jack.
I'm sure you will find it, or make one.

I still need to clean mine. You mentioned a signal generator on yours, I guess I need to read the manual to see if mine has this also. I know It will out out a standard square wave for the internal software probe calibration, but haven't done this yet.
I think I'm going to go to the service manual first and run all the standard service tests then see if anything need to be changed or fixed. I didn't take it under the microscope, I guess I should have done this when it was apart considering the drops it must have taken for the posts to break.
Well it's not hard to tear down. I may do this again and inspect the joints for any cracks. I forgot the older stuff like this might get cracks in the solder joints over time. But it was also wave soldered, so they are also glued on, maybe that helps preventing so,deer joints from cracking.

I'm assuming yours was also wave soldered?

Sounds like the repairs in the second one are coming along good. It might be done soon after you figure out that intermittent issue.
Scott

[David Hess]

I used a Philips/Fluke scopemeter for many years at work for general design and development although except for battery powered portable operation, in retrospect I could have made better use of a Tektronix 2232 or similar.

[joeqsmith]

I don't know how the board was processed. I would guess a wave or selective solder on the I/O board with as many TH parts and how the solder and flux looks.  I did not pay attention to the controller board.  They may have done some sort of reflow and selective solder on it.   

Your I/O board looks very similar to mine.  Marked up your picture.  The signal from the ASIC is fine coming onto the board.   Looks like the first switch array is fine along with the FET.   The output switch, filter and buffer are all fine.  Diodes were shorted.   

It would be interesting to compare the power draw between them. 

Powered up defaults, 17.89V @212mA
With EL active, 304mA
Fastest sample rate with EL active, 326mA

[noidea]

Well finding the plug to fit these may be slightly chanlanging because of how deep they seat into the jack.
I'm sure you will find it, or make one.

If its the same connector as the later scopemeters with the extended barrel and O-ring at the end then check this post for details

https://www.eevblog.com/forum/repair/fluke-scopemeter-12v-auxiliar-power-input/

[Scottjd]

I'll check the draw on mine next time I'm up in the lab.

I did find some documentation on mine today, yes you were correct. The 97 was released in 1991, and the 96B along with three others was released in 1997.
The numbering of flukes items messes with me. You would figure the higher number is the newer item. I ran into this when I was looking to buy my first fluke also and ended up with the 289. I guess that's what the "B" or "Series II" is for.

I found the datasheet. Wow, a whole 30K of memory. It did enlighten me to real time sampling rate vs equivalent sample rate and random repetitive wave form capturing. Looking at this datasheet I was wondering how a mobile scope from 1997 claimed to have a higher sample rate of 2.5GS/s when my digital bench scope from Rigol DS1054Z only states 1GS/s. Now I know the differences.

All I need to do now is find that 3.5 floppy disk it originally came with so I can use the optical cable from my 289 with this one. Oh wait, I guess I would also need to find a floppy drive. I think I still have windows 3.1 on floppy disks, lol.

[Scottjd]

Well finding the plug to fit these may be slightly chanlanging because of how deep they seat into the jack.
I'm sure you will find it, or make one.

If its the same connector as the later scopemeters with the extended barrel and O-ring at the end then check this post for details

https://www.eevblog.com/forum/repair/fluke-scopemeter-12v-auxiliar-power-input/

Thanks, looks like some usefully information in this thread. I'll have to browse though it
This opens my options, I have plenty of 12V switch power supplies over 300mA output, most are 1A and higher. Still I'm sure the charging is done from inside the scopemeter so even with a better power supply this won't change the charge times.

I did find that the unit will run off any voltage from 12V to 20V minimum of 12W output. And the original battery took 21 hours to charge for 4 hours of use, the original battery was also rated at 2000mAh capacity. The replacement battery mine came with is only a couple months old and rated for 4800mAh, so at the charge rate the meter give to the battery it woild take 2 days to fully charge my nicad pack. With the whole nicad battery memory issue it's better to fully charge and fully drain so I will probably use my RC hobby charger to charge it instead and 3D print some sort of box with battery contacts to hold the battery for my hobby charger.

[joeqsmith]

Service manual for the 97 may be found at:

http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=12&cad=rja&uact=8&ved=0ahUKEwjzxoqQ-p7QAhUYz2MKHec2CdE4ChAWCDAwAQ&url=http%3A%2F%2Fbee.mif.pg.gda.pl%2Fciasteczkowypotwor%2FFluke%2FPM97.pdf&usg=AFQjCNG0urZ5L7CJBEdEXC_EKbaYB_ojDw&sig2=kjOmZLoepVWRHkjyyfb4xg

[joeqsmith]

I did find that the unit will run off any voltage from 12V to 20V minimum of 12W output. And the original battery took 21 hours to charge for 4 hours of use, the original battery was also rated at 2000mAh capacity. The replacement battery mine came with is only a couple months old and rated for 4800mAh, so at the charge rate the meter give to the battery it woild take 2 days to fully charge my nicad pack. With the whole nicad battery memory issue it's better to fully charge and fully drain so I will probably use my RC hobby charger to charge it instead and 3D print some sort of box with battery contacts to hold the battery for my hobby charger.

Looks like I got the same pack of NiMH.  Was expecting NiCad.  I had picked up some standard C size 5000mAh NiMH as well. If it ran 4 hours, that would be plenty for what I plan to do with it. 

Also shown are the two different supplies.   I ended up snipping the ends off both and just re-soldering them.  When I looked at the one that had been repaired, it was hanging on by a couple of strands.   Used a few layers of heat shrink to stabilize it.  The T&B has a hot glue and once it cools, it's becomes stiff.   You can get an idea how thick it is from the picture.  Should hold up.

[Scottjd]

My pack is the same pack as yours, I mistaken thought it was a NiCd pack because all the manual mention NiCd. But I just checked, it's identacle to your pack, model number and all.

As far as current draw it looks like we use different displays. Mine always has a backlights on it. The only thing I can adjust is the level of backlighting. It has three levels, it turns on at full since I am not able to save my setting until I put a cr2032 cell inside it.
At full with your listed voltage of 17.88 it draws 208mA
With the light st it's lower it draws 192mA
Even with recording the wave form and avaeraging turned up all the way to something like 256 it never went over 208mA
The same goes for reading a 1Khz test signal on my bench scope with both channels at the same time.
(Sorry, I never got around to buying a signal generator)
It also seems to have a parasitic draw around 8mA without the battery in it. I took the power supply and hooked it onto the battery terminals to see this.

Scott

[Scottjd]

Ok, so it turns out no calibration is not needed. It was part user error and learning the scope interface.
I just went though multiple tests and it did good.
Not the best on reading mV, but for a meter built in 1997 it's about what I expected.
All voltage AC/DC passed, multiple military grade resistor at 0.01% accuracy passed.

It was also showing a message that it was on power when it was on battery when I changed the brightness of the LCD to high. A quick default reset seemed to correc this with holding down the F4 and turning on the power. You should hear multiple beeps if this works. I decided to do this since it had multiple owners and several setting were changed over time.

All I had for wave forms was a cheap square wave signal generator besides the test frequency on my Rigol. It also tests PWM, not a bad little unit for $20 and a quick way to test components.
I know I need to get an  arbitrary waveform generator, I just never bought one. And for now it will have to wait, or maybe I will end up selling something to get one?
If anyone has a broken HP i would interested in buying it for doing a repair.

I took some pictures and then decided to shoot a fast last minute video. Not my usual video quality but like I said, it was last minute and not a planned video. So real fast basic editing, nothing fancy so l,ease don't judge.

Scott

https://youtu.be/2LsCQmjvCh0

[joeqsmith]

Watched your video.  Looks really nice.  I really like the display.   

Looks like the problem on the second one may have been where the ribbon connects into the I/O board.  Shown with it looping back.  Sorry about the glare.  You can tell this thing was no bench queen.  It was used.  Some chemical spills the etched the plastic and some pretty deep scratches to the lens. 

I measured the current on the other unit and got the same results, about 320mA worst case.   Worse, they both draw about 32mA when turned off!

[mos6502]

Wow, the display on the B is really great for such an old piece of equipment. Leaps and bounds better than the non-B version.

I'm looking into getting some kind of portable scope myself. I don't know if a scopemeter is the way to go, though. For the price of a used old scopemeter, you can get a PicoScope, a Windows tablet and a roll of duct tape ...

[Scottjd]

Nice to see you figured it out. That cable on mine was pinched a little hard also. That was before I discovered that three posts were broken, it could explain the pinch. I thought about replacing my cable since it just looks like the weak spot now.
I don't mind the screen at all, I like it a little better then the one the 289. The graphs on the 289 are simpler graphs. I'm also surprised how accurate it was cincidering the age and surface mount resistors. Im thinking either it was calibrated at some time, or wasn't used much so it never drifted. It was better then some of the reading I had from the 289 on the lower side around 5 Volts. Still both are within claimed specs.

Sounds like they did get better over 7 year for power consumption with serries 2. Well that and chip manufactures were focusing more on power consumption with the start of the mobile revolution.
The good news is the batteries we have are twice the original capacity.
The bad news is the standby draw, I guess it's the battery charging part waiting to see the battery? I want to test my 289 now, but I also run it with eneloops so it doesn't really matter. Fluke told me it could be used with rechargeable, but it doesn't have a soft option to tell the 289 I'm using rechargeables so the battery guage isn't accurate and it cuts me off when I still have plenty of power in the cells. Sometimes it doesn't matter is you call the manufacturer direct, you still don't get the correct answer.

I did notice when I was function checking it the battery still drained even when plugged in and in use. I checked the battery before and it was at 5.2v, after it was at 5.11v. So like a smart phone streaming music and screen on full bright while running GPS maps for directions. Wait, the smart phone can be fixed by using a 1A charger and not the stock USB port built into the car at 500mA.

I also noticed the side with the charger was warm, and I didn't have the rubber housing on it.
From what I'm reading the trickle charge with the fluke could end up being bad for a NIMH battery, especialy since it's main charge rate is so low. The NiCd charger with a slow charge rate and trickle won't know whe to stop trying to charge a NIMH pack. Maybe that's why the previous owner had a pack leak when charging.
I found a 2800mA Ni-CD pack for $15, I think I would rather use than and not have to worry about it when it's plugged in. It will also take less time to charge, and 4 hours run time is good enough for me. I'll use the other pack for something else.

Hmm, I wonder if my infrared to USB cable will work with the 96B serial communication port?

What do you plan to do with the second one now that you have both up and running?
How good does the single generator work on your models? I didn't even know they made one with a signal gen, kind of nice.

Scott

[Scottjd]

Wow, the display on the B is really great for such an old piece of equipment. Leaps and bounds better than the non-B version.

I'm looking into getting some kind of portable scope myself. I don't know if a scopemeter is the way to go, though. For the price of a used old scopemeter, you can get a PicoScope, a Windows tablet and a roll of duct tape ...

When it was left for me I didn't think I would care for it or like it. But I have to say I've been impressed considering you can grab one in eBay for $50
(Removing battery comments)

Scott