[Amps] SB-230 Power Question

Carl km1h at jeremy.mv.com
Tue Mar 19 17:35:09 EDT 2013


There should be very little difference in the power 80-10M, the tube is good 
to 450 MHz and I get the same output on 6M as I do on HF.

Carl
KM1H


----- Original Message ----- 
From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
To: <amps at contesting.com>
Sent: Tuesday, March 19, 2013 11:21 AM
Subject: Re: [Amps] SB-230 Power Question


> On 3/19/2013 3:55 AM, K4MT wrote:
>
> Its been a very long time since I owned an SB230 (bout 30-35 years, but 
> IIRC this is pretty much typical.
>
> 73
>
> Roger (K8RI)
>
>
>> I recently acquired a SB-230 thinking the tube was probably bad with an 
>> idea of doing a GI7B project. To my surprise the amp puts out 650 watts 
>> plus on my peak reading wattmeter on SSB 80/40 Meters with 100 W drive..
>>
>> On the bands from 20 and up the power output drops.  20 Meters is about 
>> 550, 15 meters about 350-400 and I  have not tried 10m.
>>
>> I recapped PS, rebuilt tube grid circuit and repaired some bad soldering 
>> and out of tolerance parts, replaced grid bypass capacitors, removed 
>> entire tank circuit and band switch. Cleaned bandswitch and 
>> cleaned/resoldered all connections.
>>
>> Still power on higher bands drop as above.
>>
>> Any experts on this amp out there who might have an idea what might be 
>> going on. Is this a sign of a weak tube?  Since I get so much power 
>> output on 80/40M I would think the tube must still have some life in it.
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>
>
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