EEVblog Electronics Community Forum
Electronics => Repair => Topic started by: VE7HR on July 10, 2023, 03:09:48 pm
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I have this 6060B sitting on bench driving me crazy.
I was hoping these was someone out there with with experience repairing them or a working one that they are willing to open up a share some measurements.
I have gone down many rabbit holes only to find obvious errors in manual or omissions in service manual.
Wrong pin numbers or waveforms that cannot be possible.
Unit has no obvious faults after visual inspection. Soldering is good. All power supplies are clean and within specifications as far as I have found. No burned components or traces on the top side of PCB.
I be
I’ve the 6 electrolytics have tested good.
It powers up and passes self checks with no errors.
But
It comes up with 2 annunciators shown on display and have been unable to find the source of them and one other bigger issue. They are probably related.
VF and RV. Yet to sort out have they are triggered. I think internal to the microcode.
With the power turned off there is a high impedance between the load terminals. I can’t remember exact reading but at least 6K.
But here is the big issue.
But when you turn on power the resistance between the load terminals is in the milliohm range.
I have so far replaced one CA3069 that I blew up probing around and it restored operation to where it was pre probing.
I also have the main TVS out of circuit.
The manual I have has SA pattern for a 2.XX Rom and. One is 3.XX.
Running the trouble shooting tree has not got me anywhere fruitful.
The SA testing waveforms have not lead me to solution. Several have differences but I have little confidence in accuracy in several places.
I am about to go down another rabbit hole but will spare everyone unless I find some interest
Does anyone have any ideas. ?
Thanks
Dave
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Sounds like the device thinks something is connected. Faulty ADC on the input?
Another possibility based on the changing input resistance: something must switch that. Relay, FET,...). Find that component and remove it (=remove short on input), then see how the device behaves.
What is the other rabbit hole you consider?
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It looks like it is coming on in CC mode and enabled. That in itself is unusual but might be an option.
The "UNR" is normal as it is in CC mode with no load.
I don't know about protection. That might be normal with an unconnected load. I can check as I have one of these.
What happens if you actually try to use it with a minimal load in CC mode (make sure you get the polarity correct)?