Author Topic: A new addition to the lair...  (Read 6811 times)

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Offline slateraptor

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A new addition to the lair...
« on: February 09, 2012, 07:43:09 am »
Forgot to ask the assets manager to run a records check on which lab the DMM came from before leaving the warehouse; should get a response by sometime tomorrow. Needless to say, the meter is in absolute pristine condition and I'm still stoked that I've managed to land 4-wire capability without having to make a trip to the university lab at such a cheap price...acquiring Kelvin probes and a solid pair of unshrouded probes is another story though. Auction photo and after clean up pics attached below.

EDIT: 1 set each of Probe Master 8044S and 8018S to compliment the new bench DMM...good enough for government.
« Last Edit: February 09, 2012, 10:04:14 am by slateraptor »
 

Offline saturation

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Re: A new addition to the lair...
« Reply #1 on: February 09, 2012, 01:03:04 pm »
Congratulations!  Just beware that series uses a 10 year Li backup battery to store calibration data; when it goes so does the cal.  You may want to serious consider replacing it before it goes.
Best Wishes,

 Saturation
 

Offline slateraptor

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Re: A new addition to the lair...
« Reply #2 on: February 09, 2012, 01:53:34 pm »
Thanks for the heads up. I recall reading about that battery for retaining calibration data in the operator's manual but didn't think twice about it. :P
 

Offline robrenz

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Re: A new addition to the lair...
« Reply #3 on: February 09, 2012, 02:04:46 pm »
I made my own set of Kelvin leads with a simple current reversal switch to eliminate thermal EMF's

https://www.eevblog.com/forum/blog-specific/gaussian-resistors/msg71215/#msg71215

clips are still available on ebay:
http://www.ebay.com/sch/i.html?_nkw=mueller+kelvin+clips+&_cqr=true&_nkwusc=meuller+kelvin+clips&_rdc=1

Offline ivan747

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Re: A new addition to the lair...
« Reply #4 on: February 10, 2012, 01:19:10 am »
Congratulations!  Just beware that series uses a 10 year Li backup battery to store calibration data; when it goes so does the cal.  You may want to serious consider replacing it before it goes.

Can one replace a dying battery by connecting a relatively high impedance source in parallel and then swapping the old battery for a new one? I have always wondered about this, specially when the batteries power a RAM chip.
 

Offline lowimpedance

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Re: A new addition to the lair...
« Reply #5 on: February 10, 2012, 02:23:47 am »
Congratulations!  Just beware that series uses a 10 year Li backup battery to store calibration data; when it goes so does the cal.  You may want to serious consider replacing it before it goes.

Can one replace a dying battery by connecting a relatively high impedance source in parallel and then swapping the old battery for a new one? I have always wondered about this, specially when the batteries power a RAM chip.

 I have replaced a RAM backup battery in a HP8904a , according to their procedure you connect your external battery or PS through a 10k then replace the old internal RAM battery. Remove external connection, check all is still good and your done.
The odd multimeter or 2 or 3 or 4...or........can't remember !.
 

Offline BravoV

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Re: A new addition to the lair...
« Reply #6 on: February 10, 2012, 03:23:15 am »
Congratulation, looks like its still in a really nice condition.

EDIT: 1 set each of Probe Master 8044S and 8018S to compliment the new bench DMM...good enough for government.
Looks like those probe's banana jacks are shrouded, you might need to cut those plastic shroud.

At mine, I love to use the banana to bnc binding post like this here -> Click


Congratulations!  Just beware that series uses a 10 year Li backup battery to store calibration data; when it goes so does the cal.  You may want to serious consider replacing it before it goes.
As above saturation's concern, if you're going to replace that battery, please share and make a new thread for it, I might join you as well replacing mine, although last time I did measure it, the batt's voltage still fine.
« Last Edit: February 10, 2012, 03:26:27 am by BravoV »
 

Offline bfritz

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Re: A new addition to the lair...
« Reply #7 on: February 10, 2012, 04:43:28 am »
Good meter, you're going to be a happy man!

My favorite leads are Pomona 6235.  The tips have a slight bend, and are very sharp, excellent for probing surface mount devices.

http://media.digikey.com/photos/Pomona%20Photos/6235.JPG

The 6235 set comes with one red, one black, and a set of clear rubbery covers for the tips when not in use.  Without the rubber tips, you will draw blood regularly!  LOL

Enjoy you new friend.  I'm sure you will give him a good home, and treat him well.
 

Offline BravoV

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Re: A new addition to the lair...
« Reply #8 on: February 10, 2012, 06:34:58 am »
Here some infos to save your time in searching it in the service manual, its about the cmos ram backup battery that I've captured & stored while ago, its just don't have time to actually do it yet, fyi my battery is still at about 2.98 volt after all this years.

Quotes from the HP3468A service manual :





Hope this helps.

Offline nukie

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Re: A new addition to the lair...
« Reply #9 on: February 10, 2012, 07:28:35 am »
I wonder a Tadiran 3.6V battery is okay for a substitute.
 

Offline slateraptor

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Re: A new addition to the lair...
« Reply #10 on: February 10, 2012, 11:15:37 am »
I have replaced a RAM backup battery in a HP8904a , according to their procedure...

Unfortunately, there doesn't appear to be any explicit procedure for this battery replacement in the service manual. Shouldn't be problematic though...and if I goof it, perhaps one of my PMEL buddies can bail me out. =P


Looks like those probe's banana jacks are shrouded, you might need to cut those plastic shroud.
...
As above saturation's concern, if you're going to replace that battery, please share and make a new thread for it, I might join you as well replacing mine, although last time I did measure it, the batt's voltage still fine.

The specific models purchased have retractable sheaths, which was something I was explicitly looking for; really helped to narrow down prospective candidates to a small sub-set from the ridiculous options on the market. When I get around to replacing the battery, I'll def do a write-up, maybe even a video.
 

alm

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Re: A new addition to the lair...
« Reply #11 on: February 10, 2012, 10:54:04 pm »
Forgot to ask the assets manager to run a records check on which lab the DMM came from before leaving the warehouse; should get a response by sometime tomorrow. Needless to say, the meter is in absolute pristine condition and I'm still stoked that I've managed to land 4-wire capability without having to make a trip to the university lab at such a cheap price...acquiring Kelvin probes and a solid pair of unshrouded probes is another story though. Auction photo and after clean up pics attached below.
Nice catch. How much did it set you back?

Here some infos to save your time in searching it in the service manual, its about the cmos ram backup battery that I've captured & stored while ago, its just don't have time to actually do it yet, fyi my battery is still at about 2.98 volt after all this years.
I believe the typical Li-(CF) batteries used for these applications have a very flat discharge curve, until they're fully depleted, then the voltage suddenly collapses. So cell voltage may not be a very reliable indicator of charge.
 

Offline slateraptor

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Re: A new addition to the lair...
« Reply #12 on: February 10, 2012, 11:17:13 pm »
Nice catch. How much did it set you back?

US$83.60 after tax and buyer premium.
 

Offline slateraptor

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Re: A new addition to the lair...
« Reply #13 on: February 22, 2012, 07:19:34 am »
Just wanted to follow up and say that after a little over a week of extensive use, I've pretty much tossed the OE Fluke probes that came with my 87V out the window. The mini-grabber adapter is soooooooo useful.
 


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