[Amps] Ameritron AL-8d11H-- Again

[Jim Reid]

Hi all,

Ok,  I have read nearly 20 earlier posts to this list about the amplifier;
some seem to have exhibited a near same symptom as my newly
acquired unit.  I was among the very first Ameritron built,  probably
around 1995 or even more early.  It was used very little.  I bought
it just a few weeks ago from the fellow who had it;  he is "retiring"
from ham radio and has sold/given away everything he ever had
 in his shack,  shop,  roof,  etc.  He is now 94,  and not in great
health.

Anyway,  I have used this amp only on 40 meters and only for
about two weeks.  One afternoon,  turned the amp ON,  no
drive to it and only the power rocker tab ON.--  BAM, -- BAM!!!!
I instantly shut it off again,  and forgot about it as I had 
a sked,  so went on barefoot on 7088 kHz.

Next afternoon,  same time,  same band and freq.,  powered
up the Ameritron,  and it operated just fine for an hour or so,
putting out plenty of power and very carefully tuned and
loaded.  So presumed all was well.

Next afternoon,  same time, same band and freq. (nothing
changed about any knob,  etc.).  Switched on the Ameritron--
BAM and out went the meter lights;  both fuses were blown.

And the Standby/Operate rocker never left Standby when
either of the "BAM" incidents happened.  Near as I can get
from the schematic in the manual,  that rocker is not involved
with whether high voltage is on the tubes or not;  only seems
to allow the transmit relay to be energized from the base
transceiver.

>From the archives here,  and over on eHam reviews,  it seems
a solution has been to install Rich Measure parasite suppressor
kit.  So ordered that from him,  and he sent it instantly.  I have
sent him a check for same.  So have opened up the amp again
(could see no problem at all - no burned spots,  tubes appear
fine --they are labeled RF Parts,  Made in Russia-- no filaments
laying in the bottom of the bottles,  anodes not bent,  no stains
on the inside of the glass, etc.)

But to install the parts Measures has sent out here,  it appears
the amp must be disemboweled!  The tube sockets are nearly
flush with the bottom of the case;  can't even see grid resistors
under there.  So,  somehow that sub-chassis that the sockets
are mounted in must come out to gain access under there.

Any hints on how to do that from those who have been there/
done that?

Also,  Ameritron now sells a PCB for this amp which they call
a "Parasitic PCB".  Anyone know that part,  how it operates,
where in the amp,  and is it a substitute more easily installed
than the Measures suppressor stuff??  I presume this is a
recent "add" by Ameritron to later production  amplifiers
by Ameritron.  In fact this PCB part is NOT shown in the
manual PDF which can be downloaded from the Ameritron
web site.

Been off the list for a time as I sold away my big Henry amp
set-up.  Also went back and reclaimed my original 1950
class B call,  W6KPI.  Two Hawaiian calls I have had
out here the last 14 years,  AH6NB and KH7M,  just
never seemed to be very meaningful to me.  So back
I went,  hi.

Best and 73,  Jim Reid  W6KPI/KH6