On Sun, 13 Feb 2011 12:47 +1000, "cdb" wrote:

> These are simple devices - 24v @ 620mA in,  uses two TIP41's with each=20
> transistor attached to it's own centre tapped winding - in other words=20
> there are two CT windings one for each transistor on the same
> transformer,=20
> two chokes in the power feed to each, one 27nF cap for LC tuning and one=
=20
> 100nF on the secondary side.

I would look at your 24 volt power supply - perhaps the output
capacitors are bad, allowing the inverter too much freedom and that
causes the transistors to overvoltage, or maybe get insufficient
feedback and there is double switching.

You could try tacking on a biggish electrolytic cap on the 24 volt
supply and see if that makes a difference. If it improves things,
something's wrong.

Cheerful regards,

Bob

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