[djorke]

I don't know what is the right replacement for diode S3V45. I've searched Internet, but the only site which mentions S3V45 is this forum but without precise information and user is inactive from 2004:
http://www.audiocircle.com/index.php?topic=13727.msg119305#msg119305
If you know the answer - tell me, please

[randytsuch]

Hi
Are you sure that's the right part number?
I did not find anything with a google search either, and if it was a good number, there would be some hits, even if the part has been obsolete for a while.

The other thing you can do is to replace it based on what the ratings need to be.
Is this used as part of a bridge rectifier?

Randy

[djorke]

here is the photo:

2 of 8 diodes were defective and very fragile. I broke both (you can see the line along them). They were a part of Technics amplifier.

[mgalusha]

Along the lines that Randy mentions, if you know the current and voltage ratings picking a substitute is easy. Say the S3 stands for 3 amps and the V45 for 45 or 450 volts. You could get some 1N5408 to replace them. These are 3A, 800V PIV diodes and are $0.44 from Digikey. With diodes using a higher current and voltage rating should be just fine. Now, if the originals blew for some reason finding out why should be on your to-do list.

mike

[randytsuch]

2 of 8 diodes were defective and very fragile. I broke both (you can see the line along them). They were a part of Technics amplifier.

2 of 8, OK, sounds like a bridge. 
The S3V45 is the part marking, not the part number.  There are tables around that translate part marking to part numbers, but I would just replace them by ratings.

If you know what the AC voltage is out of the transformer, then you can figure out if they are 45v or 450v, although I would guess 45.

The 1n5408 diode the Mike suggests will work fine, although if it was me, I would either put in a schottky or a fast recovery, they should give lower switching noise.

Randy

[mgalusha]

The 1n5408 diode the Mike suggests will work fine, although if it was me, I would either put in a schottky or a fast recovery, they should give lower switching noise.

So would I but I was looking toward an equivalent part.

BTW, if you do measure the transformer voltage be sure to use diodes rated at least 3x the measured transformer output voltage as the peak to peak voltage is 2.83x whatever you measure.

[djorke]

For my old and only amplifier - Technics SU-V8X, I bought 1N 5402 diodes and 2 transistors 2SA 3281 and 2SA 1301 - it's working well so far.
randytsuch and mgalusha - thank you for helping me!

[randytsuch]

For my old and only amplifier - Technics SU-V8X, I bought 1N 5402 diodes and 2 transistors 2SA 3281 and 2SA 1301 - it's working well so far.
randytsuch and mgalusha - thank you for helping me!

Thanks for getting back to us.  I have given help in the past, and never heard the final outcome, nice to hear that you got it working again.

Randy