Hi,
Having a problem with the filter caps on my model 42 AK. I clipped the ground to the caps and replaced the caps outside the "tar pot". I put one cap (1.0mfd)outside by the rectifier tube at the F1 wire and to ground. I put the other two on top, one filter cap(2.2mfd) at the +B,R.F. and the other by-pass cap (.5mfd)to the +B Det. and both to ground just like the schematics show. Now I have way to much B+ (335dc)at the terminal board at +B,R.F. and +B.2nd A.F. I put resistors inline to bring down the voltage in specs but I have a loud hum or ossilation at the speaker. I really don't know what the values are suppose to be for the caps. Any help would be appreciated.
Thanks
Bud

Hi, I looked up the schematic in a NRI manual and they show the caps as; R-f filament bypass (0.3 mfd @ 200 vdc)and R-f plate bypass (0.05 mfd @ 400v) in one can. Other caps are speaker filter (0.3 @ 450); detector phone (0.002 @ 500) and detector grid (0.00025 @ 500v).

I have not worked on this model but similar AK's had 2 filter chokes in the can along with the caps. Are you sure you have not bypassed the chokes. The filter chokes are listed as 1320 ohms total.

Ed.

Hello Ed,
According to my Atwater book, the values differ than from the NRI manual. I have a NRI manual as well and the figures and names do not agree with the Atwater book that I have. According to it, the values should 1.5mfd on three filter caps and .5mfd on the two by-pass caps in the can. I haven't checked the ohms on the chokes as yet but will first thing tomorrow. The reason I replaced the caps to start with was the "tar bucket was getting hot so I checked the caps and found what looked like one was shorted. I might have more problems than with the caps being shorted but checking the ohms should tell me something.
Thanks
Bud