>
>
> I read and reread the manual. Yesterday I 'undid' the hacking which I
> suspect was an emergency repair and the change of some of the resistors in
> the Aux/key line from K11. This is mentioned under 'Important Note' on p.
> 22 of the manual.
>
> The comment about the v on the Relay line from J3 got me started thinking
> in the right direction. Both K11 and K10 were taken out of the circuit and
> K10 was strapped to make it work in low power CW only because it was really
> transmitting in Stdby. After I undid the QSK board 'mods' It would not go
> into transmit at all but the keying was working between J3 Relay and J8
> Key/Aux so I knew that both K11 and K10 were back in the circuit and
> working.
>
> OK now the Red lights are still not coming on except at start up. So I
> started tracing the Blue wire Term 1 from the Switches to the CB1
> Power/Control board and found that the signal was reaching the board when
> the CW OR SSB switches were activated. Tracing to the next component
> showed that D112 was shorted. This was replaced and but I lost continuity
> with the next part again I could not see anything wrong on the top of the
> board so I took all the cap screws out, mounting screws and removed the
> power supply board. On the bottom of the board there were two burned traced
> for Term 1 and Term 2 both were missing a full inch of material. I repaired
> the board traces and ohmed out all the diodes, transistors and resistors
> Most of it was working as the timer, K6 and the lights were working for the
> start up timer but not going back to Red for Transmit Ready.
>
> Fired it up again and now I can get Green lights then back to Red when I
> hit the CW OR SSB buttons! Yea...!! I short the relay cable and can hear
> the TR Relays so that is working. Check the power and it seems to be
> working FB now transmitting from Red lights and Not Green as before AND I
> can transmit in HI/SSB as well so ALL functions are now working.
>
> Not sure what actually burned the traces off the board but Trace 1 is the
> TR Enable line from the CW and SSB switch and Trace 2 is the Plate over
> current line.
> On the power supply board D111 had also been changed so this could have
> pulled some current on the Trace 1 from the 28V bus if.
>
> In any case the '78' seems to be working 100% at this point. I have spent
> about 2 full days on this - a lot of learning for me as the Amps I have
> worked on before have had simpler control circuits so this was a 'stretch'
> for me. Usually you have to pay extra for used gear with this 'interesting'
> problems and learning situations!
>
> Paul
>
>
>
> Message: 1
> Date: Thu, 21 Jan 2010 20:24:15 -0500
> From: Paul Gerhardt <phgerhardt@gmail.com>
> Subject: [Amps] Alpha 78 Control Circuit 'Issue'
> To: amps@contesting.com
> Message-ID:
> <bf7299be1001211724y7a5e250dobc6124bc844f93f4@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Any Alpha 78 techs?
>
> Am having trouble with the control circuitry.
>
> TR switching works if in standby. (it is putting out power in 'standby')
>
> When CW OR SSB buttons are down the 78 stays in Transmit.
>
> 60 sec timers is working
> HV is working and switching from Hi to Low
> RF power output is good
> Meters all seem good
>
> Shorting Relay Jack in standby (both CW AND SSB buttons 'out') causes T/R
> switching and RF Sensing (to inhibit T/R switching with input) works
> in 'Standby' .
>
> When CW OR SSB button is down T/R switching is 'locked' in Transmit Relay
> Jack (open or shorted) makes no difference.
>
>
>
>
> --
> Paul Gerhardt
> K3PG
> http://pgerhardt.blogspot.com
>
>
> ------------------------------
>
> Message: 2
> Date: Fri, 22 Jan 2010 02:21:19 -0500
> From: Paul Gerhardt <phgerhardt@gmail.com>
> Subject: Re: [Amps] Alpha 78 Control Circuit 'Issue'
> To: amps@contesting.com
> Message-ID:
> <bf7299be1001212321i3b346091uc15c983f1e9929e7@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Thinking about the control voltage 20V or so being present at the relay
> jack
> even in Standby lead me to discover that the QSK board CB-3 has been
> modified. The trace to the Aux/Key jack has been cut and the relay jack is
> 'strapped' to the control circuit ALL the time. Anybody know the reason or
> logic to this? This means that the exciter keying relay is 'disconnected'.
> Before I start to wire it back to 'stock' is there anything else to
> consider
> or changes that are recommended on CB-3?
>
>
>
>
> On Thu, Jan 21, 2010 at 8:24 PM, Paul Gerhardt <phgerhardt@gmail.com>
> wrote:
>
> > Any Alpha 78 techs?
> >
> > Am having trouble with the control circuitry.
> >
> > TR switching works if in standby. (it is putting out power in 'standby')
> >
> > When CW OR SSB buttons are down the 78 stays in Transmit.
> >
> > 60 sec timers is working
> > HV is working and switching from Hi to Low
> > RF power output is good
> > Meters all seem good
> >
> > Shorting Relay Jack in standby (both CW AND SSB buttons 'out') causes T/R
> > switching and RF Sensing (to inhibit T/R switching with input) works
> > in 'Standby' .
> >
> > When CW OR SSB button is down T/R switching is 'locked' in Transmit Relay
> > Jack (open or shorted) makes no difference.
> >
> >
> >
> >
> > --
> > Paul Gerhardt
> > K3PG
> > http://pgerhardt.blogspot.com
> >
> >
>
>
> ------------------------------
>
> Message: 3
> Date: Fri, 22 Jan 2010 17:34:07 +0000
> From: Eduardo de Vera Mateo <ea8auw@gmail.com>
> Subject: Re: [Amps] Kenwood TL 922 Repair Manual for buy it....
> To: amps@contesting.com
> Message-ID:
> <468fb7581001220934n196d5712n9268a10da41e0797@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Hello Friends !!
>
> Thanks you very much to N1RJ, N3XX, DK9IP and specially to K9DD for his
> kindness !
>
> I have now the service, instructions and 10M mods manuals, thanks to these
> guys !
>
> Vy 73 de Edu EA8AUW and I hope copy you in QRO soon.... if I have luck ;)
>
> 2010/1/21 Eduardo de Vera Mateo <ea8auw@gmail.com>
>
> > hello everyone !
> >
> > where can to buy the manual repair for my amp.? if it's in spanish
> > lenguage better if no in english lenguage it's the same.
> >
> > thank you in advanced for any news.
> >
> > Vy 73 ! de Edu EA8AUW
> >
> >
> >
>
>
> ------------------------------
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
>
> End of Amps Digest, Vol 85, Issue 40
> **********************
> --
> Paul Gerhardt
> K3PG
> http://pgerhardt.blogspot.com
> QRP ARCI 6674
> FP 274
>
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