Good point on the LED. It is in SERIES with the PTT circuit and the LED
has a voltage dropping resistor across it.
73
Thanks
73
Jim W7RY
On 2/6/2019 8:14 AM, gudguyham--- via Amps wrote:
Jim, no, its not a common problem with that amp, but that keying circuit is quite simple. The stand by operate switch may have
gone bad and it is broke in the stand by mode. Does the red transmit light come on? It wouldn't if the switch is
bad. There is sensitive connections at the xmt light and a place where the wires can easily break have a look there. DO
you have an older model with the 3pdt open frame relay? If so, maybe the coil opened up, maybe the snubber diode shorted.
Can be any number of things, but it is a simple circuit to trouble shoot. Another problem, rare but possible is a problem on the
timer/OL board. Maybe the grid trip circuit shorted and is holding off the power to the relay switch. This all can be
determined with an ohm meter by taking some voltage readings. You just have to follow the path of the relay voltage and see
where it stops.
-----Original Message-----
From: Jim Klein <k7rdx@charter.net>
To: Amps group <amps@contesting.com>
Sent: Wed, Feb 6, 2019 8:51 am
Subject: [Amps] AL-1500
Working on an AL-1500 that will not key up after time-Out delay for tube
heater warm up. Plate voltage comes up but keying circuit does not
activate.Is this a common problem with this model of amp?
Thanks,Jim..K7RDX..
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