[Amps] SB-220 no output

Warren Volz warren at warrenvolz.com
Tue Jul 25 14:29:59 EDT 2017


Yes ok, so it's only to give you a general idea on the power not actual
numbers. That explains it. 


On 07/25/2017 7:47 am, Glen Zook wrote:

> The meter reads "relative" power and, as such, the meter calibration has no meaning in terms of actual power output other than a higher reading, at any particular setting of the "sensitivity" control, means more power output. 
> Glen, K9STH  
> Website: http://k9sth.net 
> -------------------------
> FROM: Warren Volz <warren at warrenvolz.com>
> TO: amps <amps at contesting.com> 
> SENT: Tuesday, July 25, 2017 2:01 AM
> SUBJECT: [Amps] SB-220 no output
> All, 
> I ran into another hurdle with the SB-220 and am hoping someone has some wisdom. If I run RF through the AMP without power applied the relative power meter works and I can match my dummy load without issue. Side note, is the relative power meter supposed to line up on the bottom scale with actual forward watts? Ie: 100 Watts = 100 on the multimeter scale? Once I enable my rigs "amp keying" mode and transmit with anything from tune mode to a carrier I see high SWR and 0 output after the amp. 
> To troubleshoot, I hooked up my DMM and triggered the keying interface so that the relay(s) engaged. I've confirmed that both are working correctly. Oddly if I put the DMM in continuity test mode and trigger the TX mode on the amp I get a beep. So, the RF is blocked someplace inside the tank circuit or band switch? That's my best guess. Or is it possible that a bad tube would cause these symptoms? There is no deflection on the plate meter when I've put RF in. Does that mean the tube is being held in cutoff? 
> Thanks for the help again. It's challenges like this where I wish I had a local elmer to help out!

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