#51 Fluke 8520A How far does this rabbit hole go? Part 1
In part 1of this video we tackle a few tantalum capacitors that has gone dead short. We also have to replace a faulty LM340T-12 regulator after checking the voltage rails. Just how many problems does this "Working EBay Find" have?
I am at a stand still till I do more research...
https://www.youtube.com/watch?v=ULQroWJUZdwFluke 8520A service manual:
http://assets.fluke.com/manuals/8520A___smeng0100.pdfIn the first picture we have to replave C238 due it is shorted. We also had to replace R256 and 257
Here we finf C450 is also shorted. This was dragging the +15 volt rail down.
We find that U704 has a dead short from input to output. This is a LM340T-12
When you boot the 8520A on it is showing a voltage on the display. This should show"000"
If you hit 2-wire or 4-wire to test the Ohm setting you will get Error 1. This means high voltage when selecting ohms scale
After repairing the voltage rails we still have the error 1. But if you pull J19 we get no errors. But ofcourse the meter does not function.
And again with J19 removed we can go into ohms mode.
So with J19 removed the error goes away. The unit does not function but it looks like we are closer to the problem.
We still have to trouble shoot error code 01.
Err01 HV - High voltage present with ohms function selected.