Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5

40-201 had shorted capacitor
#4

No, I am not saying that I am not replacing all the paper capacitors. I am saying that I discovered this in the process of replacing them. This one would have been a deal breaker if I had applied power. Checking for shorts to ground in the B+ circuitry is always a good thing to do after or during repair and this was part of that process. The other thing I am finding as I continue replacing capacitors is that the resistors have changed in value anywhere from 19% to 57%! That was in the phase splitter circuit alone! There is no telling how many more are off value at this point. It appears that most all of the capacitors except for mica types will wind up being replaced. Many of the paper capacitors have already been replaced in the past, but I do not trust the replacements. This example goes to show just how bad these old paper capacitors can get.

I restored negative feedback to the audio circuits by adding a 5 ohm and 68 ohm resistor string at the output transformer secondary and running a new wire back to the low end of the volume control and tone control center lug like originally done by Philco. I did not have a 4.7 ohm resistor like Philco used in their late 1940 series of radios, but had lots of 10 ohm resistors on hand. I bridged two in parallel to create a 5 ohm resistor. I removed the switch and phonograph jack from the radio as it turned out, the switch was very intermittent and because of the way it was constructed it could not be cleaned internally. I might still add a phonograph input, but it will be an RCA type jack instead of the1/4" phone jack type that was used here.

Cheers!

Joe


Messages In This Thread
40-201 had shorted capacitor - by Joeztech - 12-22-2013, 11:05 AM
RE: 40-201 had shorted capacitor - by morzh - 12-22-2013, 01:08 PM
RE: 40-201 had shorted capacitor - by Eric Adams - 12-22-2013, 01:36 PM
RE: 40-201 had shorted capacitor - by Joeztech - 12-23-2013, 09:05 AM
RE: 40-201 had shorted capacitor - by codefox1 - 12-23-2013, 04:01 PM
RE: 40-201 had shorted capacitor - by Joeztech - 12-29-2013, 07:21 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
American Bosch Model 802 auto radio
Hello again;   I found a model 838 car radio on Nostalgia Air under United American Bosch, http://www.nostalgiaair.org/...Arran — 09:32 PM
New Philco Repair Bench
Morzh is correct. The repair bench on our website is an archived image of chuck’s original site. He no longer provides s...klondike98 — 05:32 PM
Made mistake & did not label connection
Excellent information. It is all starting to come together now and your explanation really helped since I noticed that ...georgetownjohn — 04:39 PM
Made mistake & did not label connection
Hi John, I don't have this radio, but I can supply some info: Based on your pic, pins 7,8 and 1 are used together, go...MrFixr55 — 02:02 PM
New Philco Repair Bench
As far as I know, the Repairbench does not work, and has not been working in a while. Chuck (we had that campaign looki...morzh — 01:33 PM
Radio city products 664 schematic request
Need a schematic or manual for the 664. The 663 may be similar.daveone23 — 12:38 PM
New Philco Repair Bench
Thanks Gary.dconant — 12:16 PM
New Philco Repair Bench
I tried accessing the site through our library and got the same response. It's reported to our tech gurus. GaryGarySP — 11:50 AM
New Philco Repair Bench
I am sure this is the archive, and not the Chuck's site.morzh — 09:50 PM
Made mistake & did not label connection
It's not like we are good friends with that wire and can tell it from other ptetty identical looking wires. Why'n't you...morzh — 09:49 PM

[-]
Who's Online
There are currently no members online.

>