>
>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....
>
How can we know the order of burnout, Jim?
>
>-----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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