Diodes.. debunking their message

[quadwould]

sorry for the cryptic/mystical thread title...


so i have some poor rusted out diodes the i need to replace in an amplifier i am fixing for my brother (for free.. the ungreatful sod) ... and jere is what i know/ the dioes have the folowing codes on them. 1) 15B2 and 2) 8.2B3

so i have figured the 15 and 8.2 mean Volts.. Not too hard that... but there are so many Zener Diodes that handle those voltages with so many different wattage tolerances that i am not sure which i need. i am thinking 1N5237B, 1N4738A, or 1N959B for the 8..2 volt one... but i might be totally wrong.

also i have The OEM parts list... just cryptic Kenwood in-house crap.... RD15E (B), and RD8.2E(B) respectively.... unless the "(E)" has something to do with it...

so there are 2 questions here... anyone have a suggestion of wht diodes to use?

and Is there a coding standard for Diodes like there is for resistors?


cheers
:guinness:

 

[gyraf]

Is there a coding standard for Diodes like there is for resistors?

No.

You'll need to look up data sheets for the old ones. If you're absolutely sure that they are zeners, put in one that is same voltage but physically larger, and you'll be on the safe side.

Jakob E.

 

[quadwould]

Thanks Jakob,

thats what i was thinking, like Caps , wasn't sure.


is sad there is noy a coding system.

as for the codes and data sheets.. i have found nothing (aside from the patrs list.. criptic though it is.... (does say Zener Diode in the description... but nothing else but that anc odd code)

 

[BYacey]

You should be able to get a ballpark value or clues based on the series limiting resistor and the subsequent capacitors if this is being used as a voltage reference.

 

[bcarso]

Also the package size and lead diameter is an indication: compare each to the 1W vs. 500mW diodes, that is the 47XX series vs. the 52XX series. Although it is just an assumption, they do sound like zeners, although seeing the circuit would tell.

There are still higher wattage zeners in axial packages, although fairly rare.

 

[quadwould]

well i knoqw they are Zener, as the parts list says so.. but aside from that and the clue of voltage... 8.2 and 15 that is where the clues end.
they are 4-5mm long and 2mm wide.. so i an probabli going to go with 1watt. to be safe...

 

[bcarso]

Ah good---it wasn't clear that the parts list had part descriptions like "zener".

The only disadvantage of going to higher power ratings is that the "knee" of the zener will often not be as sharp, and the voltage not quite as high, as when using the design part. This is not likely to be a serious issue when doing only a potential doubling of the power rating.

The lead diameter is quite different between the 1/2 and 1 W parts, typically.