Identifying Diode

[CellarDoor]

Hello, I am attempting to repair an audio mixer. The manufacturer will not release the schematic and the board needing repairs is two sided, so I am somewhat reluctant to map out the schematic. The board is a 17/48 volt supply/regulator board. At some point the wires from the external transformer (20V, CT, 20V) became crossed, which blew a filter cap and a diode. The problem being, I cannot identify the numbers on the diode, the only info I have is that it says "51V" below on the PCB, and it is a small red glass diode, similar package to a general purpose 1N914. I tried using a 1N914 and one of the V regs started smoking (7815A). Thanks to any who help me..... Justin Roth
JMR Productions

 

[itsmoked]

Only a guess but could that have been a 51 Volt Zener Diode? Replacing it with a regular diode would cause lots of smoking parts.

 

[Skogsgurra]

I would reduce that voltage to 5.1 V.

Philips used to indicate zener voltage in 100 mV increments and 51 would be 5.1 V. 51 V is not a very common zener voltage, but 5.1 V is.

 

[OperaHouse]

I'd start tracing it out, form follows function. Is it supposed to rectify or regulate? Until you know what its function is, it is a bad idea to just randomly replace components. A 914 on a 50V power supply could likely just burn up on its own on a bad day, these are only rated at about 100V.

 

[itsmoked]

Ah, good point skogs! Yeah, 5.1Volters are a heck of a lot more common.

 

[CellarDoor]

Thanks...... I cross checked 51V with NTE and got Industry Number : SK51V
NTE Device Number: NTE5089A
ZD-51.0V,1W,DO-41

 

[itsmoked]

You should check your circuit to see whether 51V or a 5.1V zener makes the most sense.

Cuz both come in the DO-41 package.