View Single Post
  #4   Report Post  
Posted to sci.electronics.repair
Meat Plow[_5_] Meat Plow[_5_] is offline
external usenet poster
 
Posts: 667
Default Fender Concert amp

On Mon, 26 Jul 2010 17:54:00 +0100, Arfa Daily wrote:

"Ron" wrote in message
...
On 26/07/2010 16:39, N_Cook wrote:
Bad splitter-driver plate/anode 100K resistor, what goes bad with
them? Causing rustle noise in output. Partial crack? or something
chemical. I may
as well replace the 82K while I'm at it , but is there any point to
pre-emptively replacing all the HV droppers ? Anyone happen to know
the datecode structure for Mallory electrolytics of the 1980s?
say 4uF, 450VDC
marked
012022
235
8346B

1982 and 35/52 from 235 or 1983 and 46/52 from the last number?



Noisy 100k resistors is a common and well known problem with Fender
amps, change em all.

Ron



I reckon that goes for all amps with 12AX7 stages, doesn't it Ron ?

Arfa


I repaired an old 50 watt Silvertone a few months ago and found two 100k
plate resistors one in the splitter and one in the reverb driver that had
increased in value by nearly double. The splitter was a 12a-something but
the reverb driver was a 6-something.