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

[Paul Carr <paulcarr@barrow.com>]

Dan:

When I changed the tubes in my 811H, I noticed that the horseshoe shaped 
clamps that tension the individual pins on the bottom of the tube 
sockets were quite fragile.  In fact, several had broken off and were 
shorting out to the case and I was getting intermittent arcing.  The fit 
between the bottom of the tube socket and the case is tight. 

I would check there first for a short.

Paul (WL7PC)

Dan wrote:

> 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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