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

Philco model 18 (code 121) - HELP!
#67

Your 32K resistor probably melted due to incorrect wiring of the cap 2uFto Chassis.

I do not have 121 sch but on 124 those parts are Resistor #55 and cap #40 (part C of the multiple electrolytic). You probably shorted the resistor to GND when your cap went bust when probably wired backwards.

PS. That resistor has DC path to the chassis so it cannot be accurately measured in-circuit. The top part has a path to GND through the output transformer and Resistor 6.5 kOhm, and the bottom part has another resistor to GND. I cannot read the bottom resistor value.

So your resistance is (32K + Rtrans-prim + 6.5K) * Bottom Resistor / (32K + Rtrans-prim + 6.5K + Bottom Resistor).

If the bottom resistor is 50K then it will probably be on the order of 22K total.


Messages In This Thread
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-07-2013, 10:22 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-08-2013, 10:32 PM
RE: Philco model 18 (code 121) - HELP! - by Arran - 02-08-2013, 10:49 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-09-2013, 02:21 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-09-2013, 05:57 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-09-2013, 06:12 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-13-2013, 08:40 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-21-2013, 05:25 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 02-28-2013, 06:04 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 03-07-2013, 04:16 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 03-07-2013, 11:20 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 04-17-2013, 01:25 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 04-18-2013, 08:48 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 04-18-2013, 09:49 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 04-29-2013, 10:02 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 06-12-2013, 01:37 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 06-13-2013, 08:33 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 07-23-2013, 10:33 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 07-24-2013, 11:11 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 08-02-2013, 05:06 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 08-21-2013, 10:26 AM
RE: Philco model 18 (code 121) - HELP! - by morzh - 12-17-2013, 10:58 AM
RE: Philco model 18 (code 121) - HELP! - by morzh - 12-19-2013, 12:47 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 12-19-2013, 08:48 PM
RE: Philco model 18 (code 121) - HELP! - by morzh - 01-17-2014, 04:05 PM



Users browsing this thread: 26 Guest(s)
[-]
Recent Posts
Philco 16B Parts
The 16B's in the tombstone cabinet sport a 10 1/2" spkr vs the older cathedral sets which uses an 8". The p/p ...Radioroslyn — 12:58 AM
Philco 38-7 Oscillation
I have let this one sit because of other duties. Now I am back, and I have a couple of questions. I hooked up a Hammond ...tludka — 11:16 PM
Philco 38-7 Speaker
I know that when I first started working on this radio, I did not even have a speaker. Once I finally found one it was n...tludka — 11:00 PM
Philco 60 Squealing
I seem to remember eliminating a squeal by changing the IF frequency by a few KHz. Not that you should put too much tru...fenbach — 08:48 PM
Philco 42-390, code 121 speaker
These speakers pop up on eBay regularly, even if at bloated prices. Honestly, have not seen many parts on swapmeets.morzh — 08:38 PM
Philco 38-7 Speaker
The put-put is not like the speaker problem.morzh — 08:29 PM
Mission Bell Model 19A Car Radio
Hello everyone,  As mentioned in my last post I was going to see if the vibrator / rectifier section could be persuaded...Antipodal — 08:21 PM
Philco 60 Squealing
Wondering if I did it backwards. If a coil was wound backwards, the oscillator would not work at all. Old school...Chas — 07:23 PM
Philco 38-7 Speaker
4-ohm speaker. Black, Green leads.tludka — 07:00 PM
Philco 42-390, code 121 speaker
#87 on the schematic.  This radio had a 8" Zenith  speaker attached to it when I got it. I do don't know the hist...Stevelog — 06:39 PM

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

>