The unmodified SB-230 used -130 V to switch the relay. Clearly a buffer
relay or interface circuit is required to use that amplifier with the
K3, or any "modern" transceiver.
Scott K9MA
On 12/1/2018 16:54, Don Wilhelm wrote:
Ray,
That relay power is normally provided by the amplifier - you do not
need any voltage from the transceiver unless there is some strange and
unusual circuit involved.
Measure the voltage at the "PTT" or "KEYIN" jack of the amplifier. Is
it AC or is it DC? If AC, it will not work with the K3S which needs
for the voltage to be both positive and DC.
If it is DC, what is the polarity? It must be a positive voltage.
Many older tube amplifier designs depended on hard relay contacts for
keying that cold work with AC or DC and did not care about polarity.
In today's solid state world, one must care about such things.
On 11/30/2018 10:02 AM, Raymond wrote:
I am using my ancient Heathkit SB 230 (original tube) with my K3s. Is
there a way to get 12 volts out of acc connector to power relay?
Using K3 external plug for P3 power.
Ray
W8LYJ
Sent from my iPhone
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