Jerry, the trouble wouldn't be with the current protection, but is probably
with the crowbar (overvoltage protection) that is blowing the fuse. One of
the pass transistors may be shorted, putting too much voltage across the
output. The crowbar clamps it down and blows the fuse when this happens.
73, Mike N4NT
----- Original Message -----
From: "Jeff Stewart" <stewgoat@indy.net>
To: <tentec@contesting.com>
Sent: Tuesday, April 22, 2003 2:00 AM
Subject: Re: [TenTec] Omni C - No TX
> Thanks to Jerry I found the 20 amp fuse in the supply blown but the
> replacement fuse blew also. Unhooked the supply from the rig and jumpered
> the switch lead that goes from the supply normally to the radio and the
fuse
> still blows without the radio attached. Now I could use the schematic for
> the supply to figure out how the current protection works. At least I
have
> it narrowed to the supply and not the radio at fault for the blown fuse.
>
> Jeff
> ----- Original Message -----
> From: "JERRY JUDY" <ke8npjmj@ameritech.net>
> To: <tentec@contesting.com>
> Sent: Monday, April 21, 2003 9:45 AM
> Subject: Re: [TenTec] Omni C - No TX
>
>
> > Inside the ps is a 20 amp fuse on the ps circuit board. I would bet that
> > fuse is blown. This condition lets the recieve work but high current of
> > xmit is gone. Let me know if I am right? KE8NP
> >
> >
> >
> >
> >
> >
> >
> > ----- Original Message -----
> > From: "Jeff Stewart" <stewgoat@indy.net>
> > To: <tentec@contesting.com>
> > Sent: Sunday, April 20, 2003 10:36 PM
> > Subject: [TenTec] Omni C - No TX
> >
> >
> > While adjusting my MFJ antenna tuner, my Omni C kicked out of
transmit
> > (too high an SWR I assume). In the past, just shutting the rig down
then
> > powering up would reset it. Now every time I key the mic or use the
lock
> > position, it shuts down but will return to receive when unkeyed. The
Omni
> > and the 280 power supply both turn off on transmit but works fine in
> > receive. Both the fuse on the power supply and the radio check fine
with
> an
> > ohm meter. What have I blown? ( I do have the owner's manual but I
> there's
> > no troubleshooting section.
> >
> > Thanks,
> > Jeff
|