>Thanks Rich,and this SB 220 I repaired had been at a commercial company full
>of transmitter specialist and everybody looked for that parasitic that was
>no parasitic at all , hi!
Parasites can usually not be found without a spectrum analyzer coupled
loosely to the anode-resonance. When one sends hs dits, damped ringing
is observed at the anode's vhf resonance.
>Just by replacing this lonely diode and its, of
>course, reservoire condenser solved the problem. No chain is stronger
>than..... etc etc.
The best solution for the SB-220 (and TL922) is to remove 110vdc from the
relay's bias contacts. Also, the 100k R should be probably be connected
across the NO contacts. If this is not done, the filament transformer
can be destroyed by a bad tube.
>
thanks, Hans.
- Rich..., 805.386.3734, www.vcnet.com/measures.
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