[Amps] attaching a heat spreader to a heat sink

[Steve Thompson]

Tom W8JI wrote:

> By the way, the FET's will have a tendency to blow up on 
> higher bands using Motorola's original layout.... especially 
> if you let the drain voltage exceed 55 volts. Be sure to 
> look at the drains right at the FET's with a scope and watch 
> the peak voltage!!! The boards I played with had a nasty 
> third harmonic resonance that created some pretty high 
> voltages.

Can you remember the frequency where the problem occurs?

Thanks,

Steve