Zenerdiode help!

[Hesky]

Hello everyone,

I'm trying to track down a certain type of zenerdiode, or an alternative which can be used in this amplifier psu circuit I am currently building. The codes are:

ZD18, ZD100, ZD120 & ZD150

I can’t for the life of me find any datasheets for these diodes.
Any help would be much appreciated.
Thanks

Hesky

 

[officeboy]

Are you sure those are model numbers? And not just specified reverse voltages?

 

[jneutron]

Are these the parts?

http://www.rectron.com/data_sheets/z90-z330.pdf

John

 

[Hesky]

hello officeboy,

This is what I thought to as the code is sort of short, but I'm not to sure. I've searched for these diodes using the model number and a few places abroad stock them, well one anyway but the minimum order is 50 euros and I only want 5 of them
Thanks

Hesky

 

[Hesky]

Hi jneutron,

That looks very promising it does look like that number represents the breakdown voltage and these values will be rather high as there used in the psu of this tube amp.
Thanks very much for you help!!

Hesky

 

[Hesky]

This is the HT suppy for the 6C33 tubes which uses most of these zenerdiodes.

 

[jneutron]

Yah, looks like the number is the actual BV..

That 18 volter scares me..Vgs max for the irfp450 is 20 volts..

I'd probably sub a 10 volter there. Even that gives Idss way over circuit need. But it's safer for transients.

Anyone see sumtin wrong in my thinking?

Cheers, John

 

[Hesky]

That could explain why this fet is strapped to a huge heatsink, I'm unsure what effect diff value zd's have on the fet.

 

[jneutron]

Nah, it's just on a large heatsink for dissipation reasons.

If the Vgs max is exceeded, the device will simply fail by puncturing the gate to source oxide, making a gate to source hard short, and the device will remain permanently off.

In the old days (before the asteroid hit), I had to contend with 10 volt gate maximums...they just keep getting better, but I still prefer a good safety margin.

Cheers, John

 

[jmateus]

Strange zener marks

While in subject of zener diodes I've got one out of a JVC television set that is marked - vertically - 7 and then a 5.
One would think that's a 7.5V zener but after analizing the
circuit itself (I don't have a schematic) it seems that it must
be a zener for a different voltage... The IC works with 24V
on pin 6, according to the NTE cross reference book I have.
It's out a vertical deflection circuit with a LA 7832 IC which is the
chip that provides deflection to the vertical coils. It's attched to pin 2 of the IC giving the ideia that mantains a certain voltage
on the IC.
Could someone share some light to this broken zener as well
as the broken IC (actually has whole in it!)
Thanks in advance