Fluke 8060A Calibration Service?

[Fungus]

Is there a service manual that I'm not aware of?

Yes.

Beware that there's a few versions. Later meters had the RMS chip on a daughterboard, I think you want a manual where the RMS chip is on the main board.

http://www.download-service-manuals.com/en/manual.php?file=Fluke-9271.pdf

From what you say I think U2P5 and U2P10 means the RMS chip, and pins 5 and 10. Not sure how the pins are numbered.

Yes.

(Note: that green stuff never came off the RMS chip, so maybe that's the problem...)

Maybe.

Forgive me for asking such rudimentary questions, but:

There's a positive and negative side of a balanced cable that I can run out of my audio interface to get .190V. I also have a Leader 192A sitting around, and it has a red terminal and a black terminal (I guess red is positive and black is negative?). If I get one of those set up with .190V, should I run the positive side to the red input on the 8060a and the negative to the COM jack?

Yes.

After that's set up I can use my other cheap Innova meter to test once I find the right pins. There's a red and black cable for it just like on the 8060a, and I think the red one will go on the pin, but where should I stick the black one?

On the COM terminal.

[thared33]

The AC voltage reading isn't working at all after recapping. An electrical outlet won't give a reading and only goes to 0.02V. When I power it on while holding the continuity button I get about 99.95, so that's a good sign I think.

9995 on the ratio test does indeed mean the ADC is working, which is a good thing.

DC volts and ohms are working OK, but AC volts is not, is that correct?  If so, then I have some basic RMS converter trouble-shooting suggestions you can work with.  Voltage measurements are made with respect to the 8060A COM jack.

• Set the 8060A to 200mV ACV range.
• Connect a stable AC source of 190mVrms, sine wave, 200Hz to the 8060A input jacks.
• Measure the AC voltage at U2P5.  It should be a little less than 190mVrms, due to loading from the working DMM's input impedance.
• Measure the DC voltage at U2P10. It should be about -190mV DC.

If you do not have a signal/function generator, a function generator app running on a phone/tablet will work for the test signal source.  Connect one channel of the device's headphone jack to the meter.

I got a sine wave running at .199V @ 200hz which is close enough. I clipped some alligator clips onto the TRS cable, ran the red wire/tip to the red input on the 8060A as well as the black/ring to the COM jack. I also put my other multimeter's black lead into the COM jack on the 8060A while the alligator clip from the TRS cable was on it simultaneously, and pin 5 as noted below gave me a reading of .196V AC. Close, so I think that's fine. However what I believe to be pin 10 is going to 0V on DC. I believe the pins are numbered like so when looking at it from a normal use position and the top case popped off:

14 13 12 11 10 9 8
----------------------
|                          |
----------------------
1   2   3   4  5  6  7

[ModemHead]

Your pin numbering is correct.

So, you've found a good input and a completely missing output for the RMS converter.  But before putting a nail in its coffin, check that it has a proper power supply.

Measure the DC voltage at U2P4 (Vdd).  It should be about 5.2V.   Measure the DC voltage at U2P8 (Vss).  It should be about -5.1V.  As usual, black lead of your Innova on the 8060A COM jack, red lead on the pin.  It is not necessary to hook up the 190mVac test signal for this check.

[thared33]

P4 is 5.14V DC and P8 is -4.98V DC. I guess that's a good sign.

[ModemHead]

P4 is 5.14V DC and P8 is -4.98V DC. I guess that's a good sign.

You've determined that the RMS converter chip is powered up, has a good input, but has 0V output.  That means either the converter chip is bad, or some other fault is making it look that way.  One such fault that I can think of right now is if C25 has failed short (or near-short).

Find C25 which is a "bead" style tantalum cap just below and to the left of the piezo speaker.  Probably orange, but not necessarily.  Disconnect the battery from the 8060A, and use the ohms range on the Innova to measure across C25.  It should measure roughly 19K ohms, which is actually the sum of the resistors and trim pots across it.

[thared33]

19.9Kohms. I think my guess about the RMS chip was right. There is more green stuff on it than anywhere else. Pin 1 on the chip has it the worst, with 2 through 7 having some too, but even pins 8-14 have some. The purple cap C19 must have leaked and somehow also contaminated the top legs of it.

EDIT: After taking another, very close look, C19 was so bad that the through holes on the bottom seem to have come off. The trace on the bottom going from the negative to another through hole also started to come up a bit. I'm positive that wasn't the problem originally, but it's something else that should probably be fixed.

I really wanted an 8060A since they're cool and oldschool and I need one for testing stuff in my little recording studio but I probably shouldn't invest any more time or $$$ into it.

[ModemHead]

thared33 sent his 8060A to me for repairs.

The biggest problem was actually PCB damage from where C19 puked up its guts.  After backing out the caps I found no pads and no through-hole plating for C19 at all.  C24 was also missing the bottom pad and hole plating, meaning two caps in the RMS converter section were actually not connected to anything.  I figured this meant there was good chance the RMS converter chip was actually good after all.  But I didn't want to risk a second removal procedure so I replaced the chip with a known-working one.  I patched up the board using some squares of copper tape and Kynar wire.

Meter works fine now.  And after installing the old RMS converter chip in another chassis, it turns out that it is indeed still functional.

P.S. thared33 found the missing button under his desk, so no worries there.  And for 8060A aficionados, the serial number on this unit begins with 334.

[lowimpedance]

  good job , and another one saved.
 And ewwwww. that cap puke is truly evil !.

[Fungus]

Be afraid, 8060A owners:

[tautech]

Be afraid, 8060A owners:

Why ?
Have you never heard of a repair bodge ? 

You do what you need to do to fix stuff.

[ModemHead]

That kind of damage doesn't occur overnight.  So my best advice is:

Close inspection. Any kind of crud or fuzzy stuff is bad.  Dull or dry-looking solder joints are bad, especially when others are nice and shiny.  Look for guilty expressions on the caps.

If you're repairing a non-working unit, then re-cap it as a matter of course.

For working units with early 80s date codes and/or serial numbers starting with "3", a pre-emptive re-capping is not a bad decision.  I don't think the units made in the late-80s and 90s are at much risk, but that's based on my very limited experience.  You know your own tech skills, so you can weigh the pros and cons of "fixing something that ain't broken."

[thared33]

If I remember correctly the C19 in your other repair was the only cap that didn't leak. My meter turned out being basically the opposite - in pretty darn good condition everywhere, except my C19 was the nastiest vomit you could ever get from it. I also guess that RMS chip wasn't too affected by the green snot on it.

Great work ModemHead