Jimmie D wrote:
"Jimmie D" wrote in message
...

"Jimmie D" wrote in message
.. .

"msg" wrote in message
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Jimmie D wrote:


there are appaently 2 types, one is made to run off of 12 volts maybe
24 VDC and the other runs off of 120VAC.
I think the 120VAC initially converts it to 300VDC then aplies it to
the inverter circuit.. Still trying to find a schematic to verify. I
would think this technology could be a major help for amp builders
allowing us to build inexpensive power supplies and easily custom wind
the inverter transformers.

Please dig out the ones you have and take photos, front and rear of the
entire unit and if you don't mind, disassemble and photograph and
components. I can host the photos if you wish (email them to me).
This would _really_ help in the evaluation until any of us find
schematics.

Regards,

Michael
msg _at_ cybertheque _dot_ org

Seems i am going to be looking for a couple more as the wife laid claim
on these.


I did find some info saying the switcher was run using IGBTs.



Rats, service manual just shows it as a box, but I did find some useful info
here

http://fusor.net/board/view.php?site...y=115878692 1

Knowing the freq they switch at would be a big help


Jimmie


I must confess that I'm not familiar with "inverter" type PSU's for
microwaves. However judging by the old type you would literally be
"playing with fire" in using them for a TX PSU.
Based on the "Don't put it in unless it's needed" philosophy it
1. Won't have ANY filtering worth mentioning. In fact the output will
probably be a series of rough square waves giving about +2KV average
voltage.
2. I would be quite sure that an 807 based linear would turn into slag
with 2Kv on the plates, let alone 2KV squarewaves at about 25KHz.

This is based on the fact that microwave ovens use cavity magnetrons.
these need a small heater voltage and a beefy but rough HT supply.
They are just a diode in a powerful transverse magnetic field.
After all your coffee or soup isn't a sensitive soul about signals!

Now if you had a linear needing 2Kv or so (maybe a California
Kilowatt!!!) and a good supply of high voltage caps then you might be
getting somwhere.
You would indeed have the advantage of needing less smoothing because of
the high switching frequency of the inverter but any choke would have to
be suitable for 30 KHz at least with powerful insulation.
But with decent TX tubes not being cheap I still reckon I would prefer
one of the old HV transformers with plenty of fuses.
Best of luck!
73's ZL1BDA ex G3NIA.