Diode Identification Help Needed

[TheOtherBob]

Hello! I'm repairing a friend's old cassette deck for his car. It is instantly killing fuses. It's a Concord CX30. Sorry but I don't have any schematic.

I pulled the head unit and across the + and - there is a diode. Voltage regulator? It tests shorted either way I hook up my meter so I'm going to focus on that part first.

But I can't seem to find any specs on the part.
Here is what is printed on the part:
135
D
6M

I've tried googling a bunch of different combinations but I'm not coming up with anything positive.

Anybody have any ideas of the specs on that part?

Thanks for the help!

[Mooly]

If its directly across the 12 volts from the battery then it is for reverse polarity protection (ideally it blows just a fuse) and can be left out to test the unit. Diodes like this are directly across the incoming 12 volts. If its anywhere else its something different and the above doesn't apply.

Any high current 100 volt or higher diode will do to replace it if this is what it is.

[Adnancoskun]

Originally Posted by TheOtherBob

Hello! I'm repairing a friend's old cassette deck for his car. It is instantly killing fuses. It's a Concord CX30. Sorry but I don't have any schematic.

I pulled the head unit and across the + and - there is a diode. Voltage regulator? It tests shorted either way I hook up my meter so I'm going to focus on that part first.

But I can't seem to find any specs on the part.
Here is what is printed on the part:
135
D
6M

I've tried googling a bunch of different combinations but I'm not coming up with anything positive.

Anybody have any ideas of the specs on that part?

Thanks for the help!

[TheOtherBob]

Yup! Just like you said. It is directly across the incoming 12 volts and the ground.

Here's the catch... (and I'll confirm it later as I'm at work right now).... I'm almost positive that it is hooked up backwards compared to Adnancoskun's picture in his post above. The banded side is towards the GND.

I've got a bunch of 1n400x series diodes. Do you think a 1n4002 or higher is up to the task?

Thanks again!

[Mooly]

The above drawing is correct, if yours is the other way around then I would suggest that maybe someone has worked on it before and fitted it backwards. That would blow the fuse with a good diode.

IN4xxx series aren't up to it I'm afraid. You want something with a high current and surge current rating. A 1N5402/3/4 etc might be OK. Depends on the fuse rating and how quickly it blows. Remember that unless the unit is wired incorrectly the diode will never be called into action.

[TheOtherBob]

Ok, thanks for the clarification. I'm pretty sure I've got a 1n5402 in my supply from my old pinball machine days.

Thanks again Mooly & Adnancoskun!

[Mooly]

Your welcome. Lets hope there are no other problems with the unit.

[Adnancoskun]

your welcome....