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 ?
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
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 ?
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
Then the 2SB1240 regulator pass transistor is likely to be shorted C-E, and needing replacement.
There may be other problems as well, if your house breaker tripped.
There may be other problems as well, if your house breaker tripped.
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The house breaker was because of a defective LED bulp 🙄
Just measured the 2SB1240 and between emitter and collector i measure 56 ohm - both ways
😀😀😀
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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Maybe !
It was a LED bulb where 3 LEDs where mounted the wrong way, and when I screwed the bulb in (with power on) it said bang and the bulb exploded in my hand and the house turned dark 😀😀😀
I will try to replace it, but 10.000 thanks. 😉 😉
This forum is the top
Can you post a photo of the transistor and its heat sink?
Have you repaired pcbs before?
I have done a lot of soldering and replacement of transistors and so, so this should be an easy one 🙄
Hope it turn on in a day or two 😀
Yep.
I have just ordered 2 x 2SB1240 and hope i get it before the weekend
But i will post as soon as i have tried it 😉