[Boatanchors] Troubleshooting linear amplifier

[Jim Wiley]

Brian -

First, I have to assume you meant "non-resonant PA network" as opposed 
to "non-resident part network", otherwise your question makes no sense.

If that is true, then  comes my next question:  Has this amplifier ever 
worked properly?   If not, then I might suspect that the band switch or 
some other aspect of the circuitry is miswired, either from the factory 
or after an attempted repair.  I once had a Drake L-4B that was miswired 
on 40 and 80 meters from the factory, and could not be tuned on either 
band.

If it did operate properly at one time, and has since failed, then a 
part must have failed, either completely or partially.

The circuitry in the Ten-Tec 422 is not particularly challenging. First 
question: Does it operate properly on ANY band, when tuned into a known 
good 50-ohm dummy load?

How do you know the coupling caps are good?  Did you actually measure 
them for capacitance value, or just test to make sure they were not 
shorted?

Next, did you test to make sure the band switch is actually making good 
contact?  I have seen switches where the contact looked good but was 
burned away due to arcing so that it no longer made an actual connection.

Can you get drive to the amp?  Does it show grid current?

- Jim, KL7CC



On 4/10/2016 6:37 AM, Bry Carling wrote:
> I wonder if anybody can give me any tips on troubleshooting a nonresident part network in a TENTEC Centurion 422 amplifier.
>
> It does not seem to resonate of the right frequency. I have tried many things and is coming down to possibly being a bad band switch but how do you troubleshoot that in place?
> The coupling caps are OK. The plate and load tuning caps are tuning OK. It just doesn't resonate on any band.
>
> Best regards - Brian Carling
> AF4K Crystal Co.
> 117 Sterling Pine St.
> Sanford, FL 32773
>
> Tel: 321-262-5471
>
>
>
> ______________________________________________________________
> Boatanchors mailing list
> Home: http://mailman.qth.net/mailman/listinfo/boatanchors
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Boatanchors at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
> Message delivered to jwiley at gci.net
>