Did you ever figure out what it is on the QSK board that was blowing the 20 A
fuses?
Best regards - Bry Carling
> On Feb 3, 2014, at 9:18 PM, "Donald, K6RV" <K6RV@earthlink.net> wrote:
>
> I have been following this thread with interest because I too have a
> Centurion 422. Mine is Serial # 03A10058. Using Ten-Tec's code for Serial
> numbers: Mine was built in March, Production Run 1, Unit 005, in 1998.
>
> One of the interesting things about this thread to me is that I had a problem
> a year or so ago with my Centurion with the same symptoms. Turns out the
> problem was NOT the transformer, but was a bad QSK Board (81542). When the
> problem first occurred, I called Ten-Tec's Service Dept.,
> (865) 453-7172, and talked to Gary Green, W4CJX, who is the Guru of all old
> things Ten-Tec. He said immediately the problem was the QSK board which
> apparently is a common problem - they even have a "kit" of parts to send out
> to repair it. I replaced the parts and problem solved. You may find Bry,
> that when your new transformer comes back, you still have a problem, and if
> so, check the QSK Board. If you read what the QSK board does, it provides
> voltage and switching for the control circuits. Not saying you did not
> diagnose correctly, but you may find an additional problem with that board.
>
> My high voltage comes on instantly, by the way, as Bob said, with the Main on
> switch and not with the Standby/Operate switch
>
> I cannot say enough for the guys at Ten-Tec Service - especially Gary, and
> the Manager, Paul Clinton - and how helpful they are on the phone. When ever
> I have had a problem with any of my Ten-Tec equipment, I have called them
> first, and 9 out of 10 times, they diagnose, and tell me what to fix or look
> for. Example: My OMNI V lost the display - it went dark. I was in a sweat
> because the fluorescent display is not available anymore. Called and talked
> to Gary, and he immediately said go over to the radio and pull out the
> display driver board plug slightly (it sits behind the display board and
> plugs into it). I did, and, voila', the display worked perfectly. Turns out
> the pins were made too long on the plug and when plugged in all the way,
> short out some of the tube display circuitry. Unbelievable ! Without that
> phone call I would have chased my tail forever trying to find the problem.
> My point is, whenever you have any problem with a Ten-Tec radio - call
> Service and ask for their help.
>
> Good luck, Bry, with your Centurion.
>
> 73, Donald K6RV
>
>> Message: 13 Date: Sun, 02 Feb 2014 22:31:58 -0500 From: "Bry Carling"
>> <bcarling@cfl.rr.com>
> Thanks guys, It does appear that I was partly mistaken about how the soft
> start circuit works with the three relays. Power is indeed applied to the
> transformer whenever AC Power switch is turned on and the interlock is closed
> and the 12V is applied. I think this amp has some quite a complex circuits.
> it is a device that I had not studied at all before. Having so many
> interacting PC boards, I may have misunderstood the sequence at turn on for
> the two main switches. I hope that I have enough smarts left in me to figure
> this out carefully, and understand what is going on when the HV transformer
> gets back to me in a few weeks from Gary Brown. I will leave no stone
> unturned in checking all of the diodes, caps, transistors etc. before I start
> getting ready to apply any power. What I do know is that the 12V supply
> works, the filaments and pilot lamps light up when they should. HV
> Transformer had an intact secondary. One primary shorted. When the
> transformer gets back to me rewound, I plan to start it up on 120V at first,
> as one peson suggested and make sure I can get at least 800V or so of HT
> before proceeding further. Again huge thanks to everyone (including Robb) who
> has made efforts to guide me in this troubleshooting and repair. You guys'
> knowledge and experience are a huge help for somoene looking at this for the
> first time and pondering what the heck goes on in this wonderful box of
> tricks!
>
> 73 from AF4K Bry
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