I am in need of information regarding possible replacement substitute
finals for the Argosy radios.
The originals were Motorola MRF 477, a pair, which apparently are now
pretty much 'unobtainium' in status.
Ten-Tec told me some months back that the last sets they were able to get
for service work were very expensive.
Drivers are MRF 476 I believe, and are available.
These PA transistors were 13 volts supply, 50 watt approx. - I did look
them up for tech
specs in the ARRL Handbook.
I have a dead Argosy IID that was given to me some time back with
apparently dead finals, and now an additional rig, an Argosy Analog, has
come into play as well here
that has poor drive levels (2 watts) and low high level output (20
watts?), demonstrates noise in receive when the switch is set to high
power and at low and high power the heat sink is warming up even when in
recieve. The heat sink should run pretty much stone cold in receive, and
only warm slightly if at all in high power transmit.
Obviously something weird there.
I would really like to see both of these radios restored to service, and
hope there can be a suitable substitute found to apply to use.
I have a friend who is an excellent technician who can help me apply any
practical modifications in regard to transistor type (mounting variations)
and possible slight changes in biasing etc.
Thanks a lot for any recommendations.
Brien Pepperdine
Amateur Radio Station VE3VAW
Toronto, Ontario Canada
ARCI QRP #8773 - NORCAL QRP "ZOMBIE"
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