THIS MAY BE A HAZARDOUS SITUATION.
THE GREEN SAFETY WIRE MAY BE CARRYING FULL PRIMARY CURRENT.
The following discussion assumes that you are operating the amp
on 240V AC.
The schematic shows that the power switch is only single pole, so
is either in the red or black primary line. The other side of the
240 is shown always connected to the transformer. The green
safety wire is attached to the chassis. If the power transformer
primary is somehow shorted to the case near the center tap (where
the two 120v windings are connected together with jumpers) you
could have 120v connected to one half of the primary. This would
produce full plate voltage, but would double the current on that
half of the primary. The little green safety wire would be
carrying full primary current.
The first thing I would do is replace the power switch with a
double pole switch or relay to open both red and black. Check the
power transformer, with blower motor and all other wiring
attached, to make sure all primary terminals are isolated from
the case (ground).
Dave Hachadorian, K6LL
Yuma, AZ
----- Original Message -----
From: "Charles Hedrick" <cchedrick@gmail.com>
To: <amps@contesting.com>
Sent: Sunday, January 03, 2010 6:08 PM
Subject: [Amps] trouble shooting Hunter 2000c
> Happy new year!
> Well, recently I was operating this amp the power suddenly fell
> off ~200
> watts so I went to shut it down. The power switch will not
> turn it off so I
> had to unplug it. Now, I have full plate voltage, plate
> current, and have
> isolated the filament wires from the RF Choke to check that
> circuit, with no
> change. I'm stuck wondering how the AC is shorted to ground
> thus rendering
> the switch inop. The transformer is a new Peter Dahl. Where
> to go next?
> All suggestions will be greatly appreciated.
> Tnx es 73,
> Cam
> WA4JKW
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|