Another diode question. This is in a Rockman Guitar Compressor module. Any ideas what it might be? Unfortunately the text is obscured.

Quote from: Yazoo on August 15, 2024, 04:09:28 PM
 Unfortunately the text is obscured.

So is the picture...

 

In the Rockman X100 Rev.10 schematics, all the diodes in the preamp/compressor section are basic 1N914s - absolutely ordinary silicon signal diodes. 1N4148 is generally considered an identical part.

The one in the photo looks like the cheap silicon diodes I remember in Japanese gear from the 80's. whatever it is, I think it's highly unlikely to be special. On the contrary, I'm pretty certain it's extremely ordinary.

I've managed to have a look at the real thing and it turns out to be a 4.7V Zener diode.

Quote from: Yazoo on September 19, 2024, 04:01:15 PMI've managed to have a look at the real thing and it turns out to be a 4.7V Zener diode.

Well, that's not what I said, but it still fits under the general heading of "extremely ordinary"!

Which diode is this in the schematics exactly? I don't remember having seen a zener in there..

Quote from: Yazoo on September 19, 2024, 04:01:15 PMI've managed to have a look at the real thing and it turns out to be a 4.7V Zener diode.

From the package it's about a 500mW zener.

The choice of 500mW and 1W can make a difference in some circuits.  (There's even circuits which can care about the precise part as not all zeners are specified at the same test current.)

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I found a pic of the PCB.

The diode you showed the picture of is D11.  I can see a number 1N5xxx
The diode just near it is D13 and I can see number yyy231
D11 and D13 look like different parts.

My guess would D13 is 1N5231,  which is a 5.1V 500mW (5.1V at 20mA test current).
If you can verified D11 is 4.7V then it likely to be 1N5230, which is a 4.7V 500mW zener (4.7V at 20mA test current).

I think Vivek posted some stuff on Rockman compressors a few years back, both here and on the fsb forum.
You might find some info or a schematic in those old posts.