what can i use in place of 1N4757?

[daz]

Or a site i can cross parts that isn't brand biased such as NTE?

[52 Bill]

How about a 5 watt 1N5369?

What are you using it for?

[pecorporation]

Mouser:

1N4757A-TP MCC Zener Diodes

[Enzo]

Yeah, is there some reason you don;t want to just use another 1N4757?

[daz]

I just needed to be able to fix it quick and not have to wait for a mailing. I have a ton of various diodes but no 1n4757's so i was hoping for some equiv's that i might have. No one has any locally.

[Enzo]

What is it used in and what is it doing there?

If you want to sub a part, a good first step is to look it up and see what it is. If that is the correct number, it is a 51v zener. That would be a damned odd thing to find in any piece of music equipment I can think of. But I live to be surprised. And there is nothing similar.

If it was a 15v zener, you could probably have used a 14 or a 16 in a pinch. Well in those cases, since there are probably two supplies, you would change them both. But 51v? Nothing is close to that in any of my parts collections.

is it used as a zener would be here? Or is it used as a rectifier? SOmething else? By itself? Or in series with another?

Has the part been in there all along, or does it look like someone intalled it at some point? In other words, is ther some possibility the reason it is bad is because it is not the right part that belongs there in the first place?

[daz]

Theres 2 of them in series and it's a mic preamp. I have no schematic so i simply checked everything (it's pretty simple) and out of circuit that one was shorted. It's a untouched unit so no one has changed anything.

[Enzo]

So we we absolutely sure we are not misreading the number? Why would a mic pre need two 51v zeners in series?

[daz]

Positive. I have a huge magnifier, and i found them locally after all. Both were bad too, not just the one. Replaced them and all is good now. Why they used those i dunno. All i know is they were 1n4757 and they were bad.

[jrfrond]

Why would a mic pre need two 51v zeners in series?

I'm curious about the same thing. Got a schematic Daz?

[daz]

No, but it's a mojave audio preamp. I googled it but i can only find mics. And i forgot the model but i thought it was ma-2. No can find tho. Even thier website doesn't show any preamps. Maybe they no longer make em.

[Enzo]

Maybe they are rinning with no power transformer, and the two diodes are seriesed to drop 102v. That would leave from the 120v mains 18v for the circuit.... MAybe not...

[Euthymia]

Maybe they are rinning with no power transformer, and the two diodes are seriesed to drop 102v.

Might also explain why both of them were dead and why Mojave doesn't make the piece any more!

[daz]

there was a transformer in it. And i'm pretty sure now that it was a MA-2, so if you can find that schematic your inquiring minds can be satisfied. If i can i'll post it here.