The grid resistors are shown in my 811H manual as R 19 thru R22.they are
listed as 51 ohms, 2 watt metal oxide.
I have always replaced these with 33 ohms 1/2 watt , and I've never had
any problems, but then I've always replaced the parasitic suppressors with
Mr. Measure's
Nichrome (not microbe) types. Never had any more trouble that I know
of.!!!!!
carl / kz5ca
----- Original Message -----
From: "Dan" <dpipes@earthlink.net>
To: <Amps@contesting.com>
Sent: Sunday, January 02, 2005 6:16 PM
Subject: [Amps] ok ONE more time <g> Ameritron 811H
You guys have had the answer everytime so far. I bought a 2nd hand Ameritron
811H amp. It has worked very well exept .. at first start up serveral weeks
ago.. after it had been stored when i first turned it on it arec at the
vents 9right side) switched it off.. long story short after a few turn ons
and off it work great.. I get good ooutpit and great reports. Well over the
past few weeks once in a while (only when I turn it on) I woud get an arc
same place. after it has been on and after serveral times on and off during
the day it would be fine great output and no arc even when switched back on
.. seemed like only would do it after it had been off all night and then
only sometimes.. I have remoed and check for any signs of arc etc never
found anythign..
Well until today.. I switched it on.. and again a little arc that was
visable at the vents.. and quickly this time a loud pop.
Well obviously not a good thing. I remove the cover again and this time
found that one of the 53 ohm 2 watt resistors had actuall blew apart. onone
end. I shoudl mention that this time I had very little power out after the
arc/bang..
In reviewing the circuit I can ot tell what these four resistors are but I
assume it has to do with some type of bleeder circuit to grd as all four
have one log to grd the other to a small wire maybe 18 ga. (light wires..
one is yellow one is blue and the other two are red..
the yellow one is the one that blew the resistor...
The diagram they provide in the book and the parts list has to be incomplete
as the 53 ohn resitors are nto even liosted. there are two physically near
the rear of the tube cage (just to the rear to the torrid) the other two are
near the front edge of the same are... the yellow wired resistor that blew
is one of the two at the rear side of the tube cage..
Any ideas? Are these bleeder circuits ? part of the neutralization circuit?
.. Any ideas what might of caused this .. this amp sat for about 3 yrs in a
closet not used.. before I got it..
any ideas woud be of help. Could a tube of caused it? what else shoudl I
check thanks
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