AOIP PJ6301 schematic

[tatel]

I have one last thing to fix, the binding posts of the device are in really bad shape and needs to be replaced, but i can't find anything  that can be adapted
(Attachment Link)
The back thread is 4mm, quite long, and they allow a wire to be clipped. Thay allow to use safety plugs.
Anyone have seen something similar?
Thanks!

I have... but it comes on an AOIP resistor decade box. Identical.

[masterx81]

I have too an aiop resistor box, but i use it 
I've rebuilt them using cyanacrilate and sodium bicarbonate. For a 60v device i think that i not have insulation problems.
The result is not perfect, but good enough.

[tatel]

Here it is... I'm going to machine the new parts from teflon

[tatel]

Yours look much more modern than mine. Plastic isolation looks quite a lot thinner. It surprised me you was able to get the cap out. Where they already broken? Not going to touch caps on mine, just replace the isolation.

[masterx81]

I'm looking at my decade box, and not have the safety shroudings like the meter. You can replace them easily. The threads are m4, cam be found also qute cheap on aliexpress, or quality one form hirshmann or staubli

[masterx81]

I've removed the transformer, and the feedback is given by a second primary, it's a type of feedback that i not see very often, most of the times i see a feedback from the secondary via an optocoupler.
According to the de5000, the resistance/inductance of those 2 windings are :
From gnd to first tap: 285mohm / 154uH
From first tap to last tap: 265mohm/ 142,5uH
From gnd to last tap: 0.536mohm/ 588uH

Why both windings in series have an inductance that ins't the sum of both single inductances?
In general, not seem too bad

I've also found that the 2 6.8ohm resistors in series are out of spec, both at 7.4ohm. Not change much, this are here only to allow a soft discharge of the capacitor after them.

I think that the power section is good...
I've found a -15v voltage source on the board (i've still not found what generate it, i not see inductances), that is used to generate the -10v output, so the 66v are enough the 60v positive part output.
I think that is better, as the other components can be replaced.
I'm unsure about few components that were replaced by who have tried to repair it before me.
One is the mosfet, then the 2 diodes in photo:

I not know if were replaced with equivalent components.
I not know the mosfet what is used for, but i suspect for generating the output voltage (but if is generated with pwm, i would suspect that there is the need at least of a filter capacitor after the fet, but i not find any).
Now, i think that is time to use the scope for the next part of the fault finding....

Edit

Whops, the other secondaries that generate +15,-15 and +5 have gnd in common with the 35+35 taps, so the -15 is the same used for the opamps.

[masterx81]

After have replaced the two 6.8ohm resistors, the 6v and 60v ranges works very well. Allowed me to do the calibration, and are really accurate from -1/-10v to +6/+60v.
Now remain the problem on the 0.6v range, at 0v output i get near 0.820mv, and at 500mv i get 500.814mv, but during the calibration it give an out of range adjustment error.
And on the current output i still have an unwanted -2.368ma offset, that can't be adjusted...
Let's find the next problem....

[masterx81]

I've still not had time to check for other problems but, just for curiosity, normally, how is generated a constant current? Only to be able to identify the sections involved.
Thanks!

[electrolux]

Came across this thread when googling the model number. Thought I would post some PCB pics incase anyone finds them useful as there is very little info on this thing.

This particular unit is dead as it wa plugged into 230V while switched to 115V. Dont have the time to tinker with it unfortunately.

Also, first forum post in 6 years. bye bye for now.

[masterx81]

Came across this thread when googling the model number. Thought I would post some PCB pics incase anyone finds them useful as there is very little info on this thing.

This particular unit is dead as it wa plugged into 230V while switched to 115V. Dont have the time to tinker with it unfortunately.

Also, first forum post in 6 years. bye bye for now.

Wow, really clean and nice unit.
Seem aged better than mine.
Hope that have fried only few things after the transformer, from the photos not seem that much have smoked.
Comparing the output of this device with a 34401A, seem that it's pretty accurate (at least 4 digits), it's a nice unit, and i think that can be a nice addition to a workbench
Let me know if there is something that i can help you for fix it, in my unit that section is good, and i can take measurements/photos..

Maybe, it's possible to have the p/n of the FET, and maybe a photo of the diedes in front of him? I think that who have tried to repair mine before me, have replaced it, and i not know if he used a compatible part.
Really thanks!!

[Joseph_S]

Maybe, it's possible to have the p/n of the FET, and maybe a photo of the diedes in front of him? I think that who have tried to repair mine before me, have replaced it, and i not know if he used a compatible part.

What is the FET you're interested in?
I may post a high definition picture of the surround area in the analog board.

[masterx81]

I've removed the transformer, and the feedback is given by a second primary, it's a type of feedback that i not see very often, most of the times i see a feedback from the secondary via an optocoupler.
According to the de5000, the resistance/inductance of those 2 windings are :
From gnd to first tap: 285mohm / 154uH
From first tap to last tap: 265mohm/ 142,5uH
From gnd to last tap: 0.536mohm/ 588uH

Why both windings in series have an inductance that ins't the sum of both single inductances?
In general, not seem too bad

I've also found that the 2 6.8ohm resistors in series are out of spec, both at 7.4ohm. Not change much, this are here only to allow a soft discharge of the capacitor after them.

I think that the power section is good...
I've found a -15v voltage source on the board (i've still not found what generate it, i not see inductances), that is used to generate the -10v output, so the 66v are enough the 60v positive part output.
I think that is better, as the other components can be replaced.
I'm unsure about few components that were replaced by who have tried to repair it before me.
One is the mosfet, then the 2 diodes in photo:
(Attachment Link)
I not know if were replaced with equivalent components.
I not know the mosfet what is used for, but i suspect for generating the output voltage (but if is generated with pwm, i would suspect that there is the need at least of a filter capacitor after the fet, but i not find any).
Now, i think that is time to use the scope for the next part of the fault finding....

Edit

Whops, the other secondaries that generate +15,-15 and +5 have gnd in common with the 35+35 taps, so the -15 is the same used for the opamps.

I'm interested in the fet in this photo, and the 2 components under it...
As i have this small (but uncorrectable with calibration) offset first of all i need to know if the parts where replaced with compatible ones, then i'll try to search for faulty or out of spec components....

Thanks!