>
>
>Questions to those who know:
>
>Is there anybody who has experience of inserting new SVETLANA 572Bs in a
>HEATH SB200? Any risk for parasitics that the original tubes did not have?
>
>Another question: I am just repairing for a friend a HEATH SB1000 and on 160
>the switch contacts that connects the C26 270 pF doorknob are both burned.
>It seems that the switch could not take the current through this condenser?
The existing current burden is not a problem. When the amplifier
intermittently oscillates at c. 155MHz during operation on other bands,
the (open) 160m Tune-C padder switch tends to arc. A photo of a
bandswitch with a similar problem on the 80m Tune-C padder contacts is
shown on my Website. See Figure 23 - Burned ... ... ... .
>Is this a often found problem in this amplifier?
Not as common as bandswitch trouble in a TL-922.
>Where do I find a new switch ?
Ameritron/MFJ, AL-80 bandswitch is ok.
> I am planning to let the new switch contacts actuate a small high
>frequency relay that handles this hf current??
>
no help Lowering the Q of the vhf suppressors might help.
>The toroid on 160 is red not yellow, by the way. Any comments?
>
Red is ok up to 30MHz.
cheers, Hans
- Rich..., 805.386.3734, www.vcnet.com/measures.
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