Re: Re[2]: [Amps] ok ONE more time <g> Ameritron 811H

[Charlie <ad5th@direcway.com>]

Sounds like good troubleshooting technique to me. Maybe you can evaluate the 
tube further to isolate what is wrong with it.

Charlie
Ham Radio - AD5TH
www.ad5th.com
Live Blues Music
www.492acousticblues.com




----- Original Message ----- 
From: "Dan" <dpipes@earthlink.net>
To: <Amps@contesting.com>
Sent: Monday, January 03, 2005 11:05 AM
Subject: Re[2]: [Amps] ok ONE more time <g> Ameritron 811H


well thanks to everyone's help I think I have it fixed.. well not fixed but 
at least found the problem.  I replaced the 51 ohm resistor a second time. 
this time at the advice of a local buddy he said pull that tube that that 
resistor is tied to and try again. well pull the tube turned the amp on and 
all powers up without the excieing bang/pop.. and flash <g>

I did not try to load withonly 3 tubes  but seems that proves the problem is 
with the tube.. I have ordered a set as stated earlier and will have 3 
extras i guess ..
any comments about this "test"..

thanks

*********** REPLY SEPARATOR  ***********

On 01/03/2005 at 7:36 AM carl seyersdahl wrote:

> 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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