That drift could also been caused by this........
https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg1974341/#msg1974341
Took me quite a while to track it down but it is now absolutely rock stable.
OK, coming back around to this again; I suspect I have one or more defective relays just as you did, as one of my 8600A units takes a while to warm up on certain ranges. I have done some more sleuthing on the relays, measuring coil resistance and looking at the NSN specs, and here is what I think. The U6-P on the input divider is clearly a good match for that Littelfuse HE3351A0500 125Ω unit. The UF40070 and UF40069 relays seem to differ only in the contact ratings; they are both 600Ω units. The 40069 is used in the AC Converter, so will see high AC voltages - but it is only rated for DC, while the 40070 is rated for AC/DC operation. Perhaps the shielding on the 40069 was different, to be able to operate in the presence of higher AC voltages? Just a guess; that's the only spec which differs materially from the 40070.
So, unless someone sees a problem, I'd think the Littelfuse HE3321A0400 is a suitable replacement for both the UF40069 and UF40070 relays.
Agreed, go after the relays first. If you still have a long term drift then consider changing the crystal.
Not what I'd call a long term drift; it pretty much settles to the last dp after half an hour of warmup, even from cold. Before that, though, it's off by plenty of mV (10.0023 standard reading 9.987 initially). The clue that it's a relay, for me, is that switching ranges away from 20V and then back (or selecting auto) causes the error to jump up again until it settles. A crystal ought not to do that.
Now that I have what I believe to be a list of acceptable replacement relays, I suppose I'll figure out which one is the 10VDC culprit (maybe K2?) and swap it. I only ordered one of each type until I get a chance to actually test it in-circuit and confirm it works.
You can determine real quick if it's the relays. Hang your high impedance 8800A on R52 (TP11) and watch the voltage. If it drifts....it's the relays. No drift, it's something else. Next step would be to monitor the reference voltage on CR14.
Brilliant - I'll try that after the family gatherings end on Sunday.
3) There are also issues with LCD displays. The display can be fuzzy or have bleeding.
Thanks for the insight. I still need to read more of the posts... figured I'd go ahead and ask in the mean time.
I just received my first Fluke DMM when I went to pick up my second lab grade power supply (Heathkit IP-32).
The DMM is an 8022B with bleeding LCD. Worked fine when turned on in the cold garage to see if it even worked. Now, is consistently looking like this:
***see attached image since I haven't recalled the syntax to post in the message body yet***
I swapped the battery with an 8.4V Li rechargeable to see if lower the voltage had any effect... which it didn't.
Any advice, reference LCD units if that is all or anything else I should check?
Mr modemhead (a member of the forum ) has an excellent blog on many DMM repairs.
Including a nice write up of a LCD replacement like from the above linked thread.
Check it out and follow that method .
FLUKE185/TEKTRONIX TX3
I have a Tektronix TX3, along with the lesser featured TX1, it was Tektronix's attempt to compete with the Fluke 87 and expand beyond scopes. Prior to this they only had a few imported DMMs of no particular interest. Subsequently, Fluke's parent company bought Tektronix and the blue booted TX3 got a new yellow boot and became the Fluke 185 and a sibling, the 187. These were pretty high end even by today's standards. I rarely hear mention of them. Like a previous owner stated about his favorite meter , "you would have to pry it out of my hands". If anybody has any behind the scenes stories or just owned one, I would like to hear about it.
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Kind of taking a left turn with you on the thread as this is about Flukes older meters, but as an FYI, I picked up a older Tektronix model 850 handheld DMM off ebay for $50 and shipping. I was looking for the 916 when it popped up. It has good specs, continuity beep is super fast, and I was happily surprised that it tested spot on with the DMMCheck. MrModemhead did a teardown of one here:
http://mrmodemhead.com/blog/tektronix-dmm912-teardown/
I have a Tektronix TX3, along with the lesser featured TX1,
If anybody has any behind the scenes stories or just owned one, I would like to hear about it.
Mark, a member here, did a video on it several years ago.
Kind of taking a left turn with you on the thread as this is about Flukes older meters, but as an FYI, I picked up a older Tektronix model 850 handheld DMM off ebay for $50 and shipping. I was looking for the 916 when it popped up. It has good specs, continuity beep is super fast, and I was happily surprised that it tested spot on with the DMMCheck. MrModemhead did a teardown of one here: http://mrmodemhead.com/blog/tektronix-dmm912-teardown/
I thought it was legit because it was reissued as a Fluke and it is older and I think Fluke added a few new models to that series.
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John Fluke comes again in the home..
greetings
Martin
you have sold that?
I am collecting old scopes and Multimeters.
greetings
Martin
you have sold that?
I am collecting old scopes and Multimeters.
greetings
Martin
No, I wanted to bid on it and gixened 100EUR, was not enough
.
you will catch the next what is comming there
My new desire is a russia Multimeter with electro mechanical display
Got some FET recommendations in my repair thread.
Does anyone happen to know if there's a publicly viewable price list for vintage Fluke equipment? I'm just curious what my 8600A and 8800A sold for back in the mid 70s when they were introduced. My Google-fu is failing me today...
I'm just curious what my 8600A and 8800A sold for back in the mid 70s when they were introduced. My Google-fu is failing me today...
If you have time, look through the archives of Radio Electronics Magazine. When I was doing some research, I found ads for old Fluke meters and they had prices.
https://archive.org/details/radioelectronicsmagazineI don't have anytime this weekend, but maybe you will find it quickly?
Do you still have those old Fluke meters? I could be interested.
Bob
The catalog is very interesting indeed! I didn't realize that the 8600A was still for sale after the 8800A was surpassed by the 8840A. Definitely a winner, that one, despite some internet whiners who felt they were not very accurate.
All I've seen so far in those back issues of R-E has been handheld meters, not bench units - but I'll keep looking.
If the question was intended for me - yes, I still have them, and make use of them almost every day.
But there are plenty more out there, and they're not too hard to fix. I don't think I spent more than $40 on any of the 8600A units, and only one of the 8800As cost me more than $50.
Edit: yay! Found a catalog online and was able to screenshot the price list. Dang! $1099 for the 8800A - that was a month's salary for me back then.
Interesting. I was curious about the original prices too. Even $299 USD for a 8000A was big bucks back then. (That's almost $1600 USD in today's dollars)
That list is too early for the 8010A and 8050A which came out quite a few years later, not until the 1980's. They would be probably roughly equivalent to the 8000A and 8600A in price although the 8050A doesn't have auto ranging.
you will catch the next what is comming there
My new desire is a russia Multimeter with electro mechanical display
Truer words never been spoken
, I've snagged this Fluke 8060A from the Kleinanzeigen for 15 euro coins. As usually, "no battery", "not tested" and so on, today the Hermes kid brought it and I was expecting the worse looking on the significant grim outside, so I did a Dave an open it before starting it, cleaned the insides (not too bad) and the outside (miserable), put a Panasonic alkaline, turned on and been blown: It was FRAGGIN DEAD ACCURATE on all ranges
!!!
Well, looking on the back I've seen that was calibrated in 2010, but it was also made in 1981 !!!, how the hell they were able to make them so good
?!?!?
Anyways, now he got his place on my desk and you could enjoy some pictures, my mains frequency it's really 50Hz
.
Cheers,
DC1MC
Nice find, DC1MC, although the date codes look like 1985 to me.
I would look very carefully at the bases of all the electrolytic capacitors and consider replacing them anyway. I used my 8060A since new for over 30 years before it quit, due to leaking caps. Fortunately, the damage was not too bad and I replaced all the caps as per Modemhead.