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
From: measures <firstname.lastname@example.org>
To: sm5ki <email@example.com>; AMPS <firstname.lastname@example.org>
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
>>the switch contacts that connects the C26 270 pF doorknob are both
>>It seems that the switch could not take the current through this
>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.
>- Rich..., 805.386.3734, www.vcnet.com/measures.
>FAQ on WWW: http://www.contesting.com/ampsfaq.html
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