Hans....Check the small RF choke that is on the output of the tank......I
had one of these chokes open up and cause the exact same
problem....
Good luck!
73
Jim W7RY
-----Original Message-----
From: measures <measures@vcnet.com>
To: sm5ki <sm5ki@algonet.se>; AMPS <amps@contesting.com>
To: <amps@contesting.com>
Date: Sunday, January 23, 2000 1:47 PM
Subject: Re: [AMPS] UrgentSwedish questions
>
>>
>>
>>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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>
>
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