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73, Rainer DF6NA
Am 11.01.2021 um 20:17 schrieb Pete - GM4BYF via groups.io:
Just seen your message. I have a circuit diagram somewhere,
having repaired mine several times. One thing to notice is that
the coaxial relays have insufficient isolation on their own, so
the input circuit has an additional isolation relay to earth it
when on transmit. I also found that a delay of 0.3s was
necessary to protect the output of the preamp and allow time for
the relays to change over. Get back to me for more detailed
information if required.
On 10/01/21 18:49, Anthony Coldman
via groups.io wrote:
I have a SP23MKII mats head preamp, its
I wonder if anyone has a circuit for it
with the component value, I suspect one of the 2 Gas Fet,
but unsure on what they are, they seem to be the same
possible MGF1302 but not 100% sure.
Does anyone have any information that
may help. Its quite an old unit so is there a better
replacement device available now?
Regards Anthony G7LRQ