Products > Test Equipment
Restoring / Repairing an old Fluke 8000A
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joeqsmith:

--- Quote from: med6753 on January 12, 2020, 07:15:54 pm ---It's not a time waster. It's a time saver. Why troubleshoot the obvious? And why risk damaging other components if you have shorted capacitors. Sorry, but I'm in the opposite camp...it's smart troubleshooting. Then you'll be able to go after the real issues.

And in ref to your vintage radio....most likely has wide component tolerances. Not unusual in consumer gear. But I'll bet if you DID recap it the performance would improve.

--- End quote ---

Had you taken the time to read it, I did have to recap it eventually.   It's very possible that the lack of reading and education is what drove us to swapping parts as a way of troubleshooting.   
med6753:

--- Quote from: joeqsmith on January 12, 2020, 07:20:09 pm ---
--- Quote from: med6753 on January 12, 2020, 07:15:54 pm ---It's not a time waster. It's a time saver. Why troubleshoot the obvious? And why risk damaging other components if you have shorted capacitors. Sorry, but I'm in the opposite camp...it's smart troubleshooting. Then you'll be able to go after the real issues.

And in ref to your vintage radio....most likely has wide component tolerances. Not unusual in consumer gear. But I'll bet if you DID recap it the performance would improve.

--- End quote ---

Had you taken the time to read it, I did have to recap it eventually.   It's very possible that the lack of reading and education is what drove us to swapping parts as a way of troubleshooting.

--- End quote ---

I will admit I did not read the entire thread. All I've tried to present is an opposing point of view. But apparently you want to resort to snide remarks and sarcasm. As far as I am concerned this debate is done.   
GregDunn:
I had both an 8800 and an 8600 which I bought online and they exhibited semi-random displays but when changing modes would occasionally do something sensible for a few moments before becoming chaotic again.  One step I'd definitely try before pulling out the soldering iron is to put some Deoxit into the mode selector switch contacts and exercise them all vigorously for a minute or two.  Often bad contacts will cause extreme and puzzling behavior all by itself.  Cleaning them at least ensured the meter was in a consistent state for further troubleshooting and prevented me from chasing down nonexistent gremlins.  IIRC one of the meters required no further action - the other one ended up having a defective IC in the regulator circuit.

I also "fixed" a Keithley 197a the same way.  If a meter has sat for months or years, oxidation is often rampant.
joeqsmith:

--- Quote from: med6753 on January 12, 2020, 07:44:02 pm ---
--- Quote from: joeqsmith on January 12, 2020, 07:20:09 pm ---
--- Quote from: med6753 on January 12, 2020, 07:15:54 pm ---It's not a time waster. It's a time saver. Why troubleshoot the obvious? And why risk damaging other components if you have shorted capacitors. Sorry, but I'm in the opposite camp...it's smart troubleshooting. Then you'll be able to go after the real issues.

And in ref to your vintage radio....most likely has wide component tolerances. Not unusual in consumer gear. But I'll bet if you DID recap it the performance would improve.

--- End quote ---

Had you taken the time to read it, I did have to recap it eventually.   It's very possible that the lack of reading and education is what drove us to swapping parts as a way of troubleshooting.

--- End quote ---

I will admit I did not read the entire thread. All I've tried to present is an opposing point of view. But apparently you want to resort to snide remarks and sarcasm. As far as I am concerned this debate is done.

--- End quote ---
It's not a snide remark.   I believe our education when it comes to technology and science is suffering and in place of it, we get tales.  I am not a service tech and don't do a lot of repairs.   Of the last few things I repaired at home, 

Several of my own power supplies, always a transistor or diode failure 
Used Fluke 189, a wannabe tech lost one of the switch contacts
Used Fluke 97, damage to front end and solder fracture
My bench meter & GPIB controllers, damaged ICs from lightning strike
Neighbors sound system, solder fracture
Friends calculator, solder fracture
Laser printer, bad Alum Elec (only changed one)
RF generator, bad relay
Used spectrum analyzer,  blown mixer
VNA, bad mechanical switch
Friends old service monitor, bad Alum Elec.
Old ham radio, solder fracture
My old LeCroy 64xi DSO has been repaired at some point and that area appears to be a problem.  Reseating the connectors solved it.
I have an old Tek TR current clamp from the 60's that was in very poor condition that required several matched transistors but no caps.

...
RLC meter, damage synthesizer IC
Electrometer, damaged op-amp IC
Old HP logic analyzer, tant cap in power supply, one bad but replaced two of them

Now, my old LeCroy DSO has had several tants fail.   I would guess I have changed 10 or so over the years.   Just not much of a trend really.  I would have done more harm than good recapping these entire systems.   

If anything I would say my trend is toward mechanical failures.  Solder joints, relay, switch..   Besides the people wanting to replace all their caps, the other common repair I see posted a fair amount is where people will reflow every connection.   

****
Forgot a few recent ones....
vinlove:
Fluke 8000a is not that easy to buy in here. It is kind of a rare gear being the 1980s product.

It wasn't that cheap either. One is enough for me, unless I went out and happen to bump into them for impossible to resist price or free, I wouldnt intentionally keep buying them just because I like it.

Plus I have many other DMMs mostly cheap but recent ones working well.

I just wanted something sits on the bench and on all the time, so quickly measure volts and ohms on fly instead of opening the draw, pulling out the handheld dmms.

The 8000a already looks cool on my bench with the red display. It worked better yesterday after having been switched on for a few days. DCV reading is good. Then when it is changed to ACV or ohms, it goes unreponsive to the probes.

Need to leave it on for a few minutes and switch off and on start again, then it works again.

I too, repaired a few gears recently, mostly on the old antenna tuners non working, and when I troubleshooted, it was usually dry solder joints, loose connection somewhere. Just resoldered them, they worked.

Also repaired another old bench DMM called Black Star 3225. It was dead on arrival. When opened up, there were fuses one at the back of the unit, one inside the unit. The inside fuse was blown. Replaced it and worked. Easy fix. But this thing needs serious calibration. Ohms reading works fine but volt reading way way out of tune.

Recapping is a painful work because it takes time and money. But most of the time it works well after.

Once I got this old tube radiogram from 1940s size of a dinning table. When powered on, it made puffing noise and banging noise crackling badly. I replaced about 30 caps and dozens of resistors, took a few weeks for the job. It worked perfect after that. And that was the only way it needed to work perfect.
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