Powersupply voltage problem

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u301021

Account closed
2010-06-08 9:22 pm
Hi there.

I have a Marantz MR 2020 (MR2021) there is dead
A fuse in the house installation was blown and all the power in the house was gone.
I replaced the fuse at got power again, but after that little episode the Marantz MR 2020 was dead.

I have tried to measure some voltage on the power supply, and found a "funny" thing.

In the schematic there is a point where there should be -27 V but i´am measure -43 V
I believe it is on the board (6.2) in the schematic the makes the trouble.

Here is a little cut of the schematic and also the complete schematic.

Can somebody help me to get this fixed ?

huhu.jpg


The schematic = https://www.google.dk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=2ahUKEwjyuYLYgMXlAhVDdJoKHT-SBtgQFjABegQIBhAC&url=https%3A%2F%2Fwww.vintageshifi.com%2Frepertoire-pdf%2Fpdf%2Ftelecharge.php%3Fpdf%3DMarantz-MR-2020-Service-Manual.pdf&usg=AOvVaw3ozfOJwTFq7AlqAhReJq0Q
 

rayma

Member
2011-04-29 8:37 pm
:D:D:D
Thank you - i will try to find a new or a replacement and replace it.

But can a transistor really go dead cause of housebreaker is turning off ?

Could have been a voltage transient, the Vceo rating is 32V.
Maybe the regulator's output to ground was (is) shorted.
That would impress the entire 39V across the transistor, not good.
Do some more checking before replacing parts.
 
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