Hi,
I want to replace a dead diode on the main circuit board of the JVC JA-S11 (amplifier). The service manual says it's an MR-1 made by Sanken.
I can't find any information about this diode anywhere online, I suspect it's an old diode and the technology has gotten better thus making it obsolete.
I want to replace this diode, but as I can't find a datasheet anywhere online, I don't know which diode to use.
I have some 4007 diodes (on the right side of the photo) from a donor amplifier, these are a lot smaller tho. Will these work as a replacement or do I have to use different ones?
I've added the original service manual as an attachment.

Thanks in advance!

Foto of the original and replacement diode:

Parts of the service manual:

 

With more context on the schematic you can see the diodes are connected to 3.15A fuses, the 1N4007 is a 1A fuse. A 1N504 which is a 3A fuse would probably work.

 

With more context on the schematic you can see the diodes are connected to 3.15A fuses, the 1N4007 is a 1A fuse. A 1N504 which is a 3A fuse would probably work.

View attachment 235531

Thanks for the help, I don't really know a lot about circuit boards, I just try to fix my stuff when it's broken. That's why this might have been a stupid question.

 

Thanks for the help, I don't really know a lot about circuit boards, I just try to fix my stuff when it's broken. That's why this might have been a stupid question.

no problem. Of course be careful to observe the polarity.

 

While not exact specs for the MR-1, I use the NTE cross reference to get a general idea of specs for older parts like this. I also check the sub I plan on using to see how they match as well.

In this specific case, there are 2 listings for MR-1"

MR-1C ECG 116 Peak Reverse voltage: 600V Max forward Current: 1A Max peak surge current 30A
MR-1M ECG 125 1000V 3A 60A

A 1N4003 crosses to the ECG116
A 1N4007 crosses to the ECG125

 

While not exact specs for the MR-1, I use the NTE cross reference to get a general idea of specs for older parts like this. I also check the sub I plan on using to see how they match as well.

In this specific case, there are 2 listings for MR-1"

MR-1C ECG 116 Peak Reverse voltage: 600V Max forward Current: 1A Max peak surge current 30A
MR-1M ECG 125 1000V 3A 60A

A 1N4003 crosses to the ECG116
A 1N4007 crosses to the ECG125

Now that you mention it, there were 2 different versions. Some had a C and others didn't. The diagram didn't show a difference so I thought they were all the same. I removed D701-704 (you can see them on the diagram). As I didn't know that they were different, I don't remember where each specific one goes. Can I just use 3A diodes for all of them?

 

A 1 amp diode is probably marginal. Be better off with the 3 amp 1N540x series - A 1N5402 is 3A, 200PIV, and should fit the bill. Or a 1N5403, 04, 05,...08 on progressively higher voltage ratings.

 

With more context on the schematic you can see the diodes are connected to 3.15A fuses, the 1N4007 is a 1A fuse. A 1N504 which is a 3A fuse would probably work.

View attachment 235531

I was looking online some more and I found some information about the MR-1 and MR-1C diodes (D701-704 on the schematic) here. These seem to be 1.2A 400-1000V diodes. Does this mean I can use any 1.2A diodes as long as the rated voltage is higher than 29.5V? It is confusing because of the 3.15A fuse.

 

The max current rating of the 1N4007 is 1A but it has a surge current rating of 30A. Since the fuse will likely fail under a surge, the 1N4007 should be sufficient for this application. You can also use a 1N54xx one as well. Either should work just fine in this application.

 

The max current rating of the 1N4007 is 1A but it has a surge current rating of 30A. Since the fuse will likely fail under a surge, the 1N4007 should be sufficient for this application. You can also use a 1N54xx one as well. Either should work just fine in this application.

Thanks! Hopefully, I can get this amplifier fixed.