[ICOM] Re IC765 No Transmit

[Doug Perkins]

Thanks to everyone for the responses to my IC765 transmit problem.  I hope
to check out these suggestions and get back on the air soon.

73, Doug  KF8VS


----- Original Message -----
From: "Gary Fiber" <g.fiber at verizon.net>
To: "ICOM Reflector" <icom at mailman.qth.net>
Sent: Sunday, August 01, 2004 4:03 AM
Subject: Re: [ICOM] Re IC765 No Transmit


> Mike
>
> if you look at Q14 and find it defective then there are a whole lot of
> parts that can be stressed even if they check ok. First is about Q14 and
> the 2nd write-up tells you what to look for on D47.
> If D47 voltages are incorrect it was the writer technicians experience to
> change all the components listed even if they checked good as they would
> fail in a short time after the original repair was made by replacement of
> one or two components.
>
> Gary K8IZ
>
>
> Symptom: No TX output in all modes. Problem is traced to no output at J8
> connector on the RF unit.
> Probable Cause: Bad Q14 transistor amplifier on RF unit.
> Cure: Replace faulty Q14 transistor (2SC2053).
> Remarks: There may be other problems on the RF unit. Check the DC voltages
> at D47 diode.
>
> Symptom: No or very low RX sensitivity.
> Probable Cause: Bad components on RF unit, probable result of RF overload
> or lack of necessary update. Check DC voltages at D47 diode on RF unit to
> verify problem.
> Correct voltages are: Cathode side- RX: 8.5 V, TX: 13.8 V. Anode side- RX:
> 9.0 V, TX: 9.5 V.
> Cure: Replace these components on the RF unit: D42, D44, D45, D46, D47
> diodes, Q15 transistor. Check C174 and C179 capacitors for leakiness.
There
> may be other failures. Unit is not repaired until listed voltages at D47
> diode are correct.
> Remarks: If the serial number of the unit is below 01800, the unit
probably
> needs a factory update to the main unit to prevent future failure of these
> components. Call technical support for details on this update.
>
>
> Gary Fiber K8IZ
> GROL PG-19-6691
> Washington State Resident
>
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