Steve the schematic shows that 1N4007s are the diodes of choice.
Now that I have the rig apart I can report that of the 14 diodes used to
switch the 7 band combinations 1 is a 1N4007 and the rest are, I assume, the
surface mount equivalent.
I'm trying to figure out how a rig that has never had the case off it has a
1N4007? Perhaps the board failed a test after production and the repair
crew only had discrete components rather than surface mount parts!
By the way, I've now determined that the problem IS a diode failure (one of
the surface mount diodes).
73,
Rick
VE7ASR
Web site: http://www3.telus.net/ve7asr
> ----- Original Message -----
> Steve Baron - KB3MM SteveBaron at StarLinX.com
> Sun Jul 27 00:27:20 EDT 2003
>
> What diodes do they use for that switching?
>
> ----- Original Message -----
> From: "Rick Williams" <rick.williams at telus.net
> To: "TenTec List (E-mail)" <TenTec at contesting.com
> Sent: Saturday, July 26, 2003 16:01
> Subject: [TenTec] Update - Argo V low output
>
>
> Well this time I think I have found the problem! After measuring the
> voltage at a reasonably accessible area of the transmitter switching
circuit
> it looked to me like the 80 meter switch was always on. The readings on
the
> various coils were correct when the rig was on 80 metres but screwy on the
> other bands. (If anyone wants the details please feel free to contact me
> directly.)
>
> I discussed my analysis with Paul Clinton (WD4EBR, Service Manager) and
> others at Ten-Tec and they agreed that the 80 metre circuitry was likely
the
> problem. A shorted switching diode or a shorted transistor the culprit.
> They hope to get a "Care Package" with the appropriate parts into the mail
> early next week. I will now begin the dismantling process.
>
> But before I put this item to rest I have some comments to add:
>
> 1) Thanks to all on the reflector for your assistance and insight.
> 2) Thanks to Ten-Tec for the prompt response to my problem.
> 3) A 2nd thanks to Ten-Tec for a great manual (explaining all the
> circuitry in plain language) and complete schematics.
> 4) Finally, I've learned a lot and that's always fun!
>
> Of interest to readers with other rigs were Paul's final words " ... don't
> forget that your efforts to repair the rig will NOT effect your warranty!"
>
> (In a few days I'll be posting pictures of the Argo V surgery on my
website
> for those that may be interested.)
>
> 73,
>
> Rick
> VE7ASR
>
> Web site: <http://www3.telus.net/ve7asr>
>
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