[Yaesu] Re: FT-980 "FLAKY"

[Dave Jordan]

Thanks for the updates Mike,

I found the flaky LED lamp problem (for the Clarifier and Tab functions) was due
to a wire
fracture of the +5 volt (blue wire) connection to the Key  Matrix Unit.  This was
the same
location where I found another wire fracture to the SWR Forward Set control.
These wires were broke prior to opening up the  radio (not stress facture from
tinkering).
I  expect the wire after 15 years is just getting brittle and the temperature
changes
in the radio room are causing some of the wires to open circuit.

This is a scary thought since so much of this radio is hand wired, YIKES!

OK, I've adjusted the 24volts and 13.5 volt supplies. both were off...(they were
both
high when the FT-980 was last returned from the factory). The voltages were 24.5
and 13.8.  Are these
voltages critical?

After making the 24/13.5 volt adjustments the floating ALC meter now reads a
steady
state of (using the "S" meter scale) about S2 rather than S5. So, that is an
improvement, but
still leads me to believe something isn't adjusted correctly.  Again, no power
output is detected
so I "don't"  think this is carrier balance indications???

The CM coupler adjustment instructions say to adjust TC9001 (Relay Unit). The
Service Manual
and the Operating Manual make no mention of where the the Relay Unit is located.
Is this another
type-O?  I'd like to make the CM adjustment but can't find TC9001.

Thanks,
dave

p.s. Please CC: the yaesu reflector as they would appreciate knowing about
type-o's, etc.

===========================================================

Yaesu Technical Support wrote:

> Dave,
> The ALC and CM coupler alignment is on page 28 of the manual. There are
> some mis-prints in this area, and I've listed them below:
> ALC level - C.2 tune for 100W on wattmeter
> CM - E.2: adjust TC9001 for 0 Volts on DC voltmeter.
> I'd suggest performing sections:
> B - Carrier Balance (the "stuck" meter could also be caused by carrier
> leakage)
> C - CM coupler balance
> G - ALC meter sens.
>
> Also - Check TC9001 for cold solder or bad operation.
>
> Best Regards, Mike Krueger - N6MIK, Yaesu Technical Support




--
FAQ on WWW:               http://www.qsl.net/k7on/yaesu.html
Submissions:              yaesu@contesting.com
Administrative requests:  yaesu-REQUEST@contesting.com
Problems:                 owner-yaesu@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm