Audio Research SP-5

[dustmaker]

Technical question
i’m working on an Audio Research SP-5 and I want to replace one of the zener diodes. The manual parts list shows 15V 500MW 1%.

First question. I am assuming that means 500mW because all of the resisters in the area are 1/4 watt. It can’t possibly be MW. Printed on the diode is .5 M
Second question. What would be a similar part today? I looked on Mouser and Digikey and they do not have 15v zener diodes in stock plus I don’t know any other parameters of the original diodes.

Any help would be greatly appreciated

 

[llwhtt]

I would pull one of those and get the full part number off of the device. Finding a 1% Zener will be the tough part, at least one that's in stock. AR manuals are usually pretty accurate in my experience.

 

[egellings]

Zener diodes do have a wattage rating, and a 1watt, say, 15 volter would be about the size of a bog standard 1N4007 rectifier diode. A 500mW one might look about the size of a 1/4 watt resistor. Another important parameter is Izt, the specified current that must flow through the diode for it to develop its specified Zener voltage. The 1N47xx series of 1 watt diodes come in a wide range of Zener voltages.

 

[ivandezande]

Yup, pull and just read the P/N. I'm sure there's a datasheet, and maybe even still in production.

Better replace all those nasty carbon comps. ARC gear is the best because you can (and should) replace near everything.

 

[dustmaker]

I would pull one of those and get the full part number off of the device. Finding a 1% Zener will be the tough part, at least one that's in stock. AR manuals are usually pretty accurate in my experience.

I couldn’t find a 1% zener anywhere, no body has any in stock. So I contacted Audio Research Company and they have a few of these zener diodes in stock but they are expensive. They are $2 apiece and shipping charges are $15.

I also inquired about the axial e-caps with the -10%/+70% tolerance. They suggested replacing with similar tolerance items but +/-20% may work. There are limited options of the -10/+70 caps out there.

 

[ivandezande]

I couldn’t find a 1% zener anywhere, no body has any in stock. So I contacted Audio Research Company and they have a few of these zener diodes in stock but they are expensive. They are $2 apiece and shipping charges are $15.

I also inquired about the axial e-caps with the -10%/+70% tolerance. They suggested replacing with similar tolerance items but +/-20% may work. There are limited options of the -10/+70 caps out there.

There should be 2% zeners available from Digikey etc that will be just fine.

Why would tolerance need to be the same? They’re caps, not resistors. The original is awful. +/-20% is standard and much better…