Support detect error Fluke 5500A

[Ugur]

Thank you very much for your comment.
I measured the primary side of the T3 side as open circuit, so this is definitely defective! First I will have this transformer repaired and then I will test it.
I hope the problem is solved and the device works with this card.
Because this card was already installed in this device before it malfunctioned. I will let you know the result.

[Ugur]

Hello my friend,
I had the T3 transformer repaired and tried the device again, but my problem continues. This error really made me tired. If I can't find a solution after looking for a few more days, I will give up.
As soon as I turn the device on, my -15, +15, 5V regulate ICs and Q16, Q17 MOSFETs get hot. (Q12, Q14 transcitors heat up a little slower).
Although there are no short circuits and all my regulated voltages are stable, I don't understand why they are getting hot.

I removed U1 and when I turned the device on, my mosfets and transistors were cold, but my regulate integrated circuits still got hotter than normal.
By the way, I compared it with the 5500A A8 card, yes there are differences, but I saw that the pin sockets were the same at least up to the point I checked, at least it shouldn't cause it to heat up like this.
I think the 5520A A8 card can work with 5500A.
Because this card was inserted before the device broke.

[ddrl46]

Hello my friend,
I had the T3 transformer repaired and tried the device again, but my problem continues. This error really made me tired. If I can't find a solution after looking for a few more days, I will give up.
As soon as I turn the device on, my -15, +15, 5V regulate ICs and Q16, Q17 MOSFETs get hot. (Q12, Q14 transcitors heat up a little slower).
Although there are no short circuits and all my regulated voltages are stable, I don't understand why they are getting hot.

I removed U1 and when I turned the device on, my mosfets and transistors were cold, but my regulate integrated circuits still got hotter than normal.
By the way, I compared it with the 5500A A8 card, yes there are differences, but I saw that the pin sockets were the same at least up to the point I checked, at least it shouldn't cause it to heat up like this.
I think the 5520A A8 card can work with 5500A.
Because this card was inserted before the device broke.

It might be worthwhile to remove all cards from the calibrator besides the A6 and A8 assembly in order to make sure the fault is isolated to this assembly. The calibrator will happily provide DCV and ACV functions in this configuration.
When you say your regulators are getting hot, how hot are they getting? I've had a case where one of the 15V regulators was faulty which only showed up after a while or only in certain instrument configurations. This was due to them using two regulators in parallel, and since once was faulty the other had to take all the load.

[Ugur]

When I previously inserted another working A8 card into the device, it worked fine, so I think the problem is not caused by the other cards, but no problem, I can remove them.
I didn't measure the temperature, but it gets hot enough to burn my hand. The estimate may be 70-80°C. and reaches this temperature in a very short time.
I changed the 7915 integrated circuit for -15V, but the result did not change.
I had checked the parallel connected regulator for +15V, but the new ones
  I will replace it with . I will also replace the bridge diode with a new one.
But I don't understand why my mosfets and transistors are getting hot.
When I remove U1, it does not heat up. When I followed that circuit, I could not find a faulty part.

When I apply a value above AC 33V, the value slowly rises to approximately 400mV in TP12, then it gives error 1503 and turns off the output.
At the same time, TP13 also rises to 4-5 V level.
The voltages I measured in TP12 and TP13 at values up to 33V are very good and stable.

Finally, T3's A6 and B1 pins go to the 8th pin of K5, is that correct? Also depends on Q18.
Because I measured an open circuit on the board.

[Ugur]

I removed the cards except A6 and A8, but the result did not change.
As you said, one of the parallel connected +15V regulated integrated circuits is faulty. When I checked it alone, I measured an unstable voltage between 16-19 V. I replaced both of these and also replaced the bridge diode.
Unfortunately, the result did not change again.