Has anyone ever run into one of these big old solid state 6M amps? No
tubes but would qualify as boatanchor at well over 50 pounds. A former
owner tried getting 1 kw out. The amp is rated at 1 kw input so you can
guess what happened. I'm in need of a set of final NPN transistors
(4). The company is no more and the original finals were stamped with
their proprietary part number, so finding a cross reference hasn't
worked. The owner/designer never gave out actual transistor specs, even
to employees.
The V360 dates from the late 70's and has a big 24v internal supply. It
runs two identical PA boards with two finals each so the 4 finals take
20w (max) coming from driver - split 4 ways - then back together with
stated 1Kw input for PEP or 750w for FM,RTTY,CW,FSK,AM and specs say
output of 500-600w PEP and 350-450w for FM,RTTY,CW,FSK,AM. It
apparently took very little drive (<5w). An email from a former
employee of RF Power Labs said 1-2w of drive would max most and blown
finals were a very common problem.
The original finals are 0.5" stud mount (10-32 stud) and given amp
specs, it sounds like a 28v NPN rated at about 5w in and up to ~ 100w
out cw/fsk or 150w PEP rating at 50 MHz or about 12db gain figure for
each. Most of the stud mounts I've found are only in the 30-50w range
and that may also explain some of the blown finals. There may have been
a poor heat transfer problem right from the start due to the small sink
area.
I've struck out so far. If push comes to shove, there is the
possibility of some careful Demerel tool work and adapting to a flange
mount type. It is otherwise a really well designed and laid out amp and
a shame so many sit with same problem. The Philips BLW77 (SOT121B
flange) has been recommended by one person. In addition the Advanced
Semiconductor HF220-28 or HF100-28 might work at 50 MHz.
Open to suggestions and TNX in advance - Bruce, N5SIX
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