Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12) x

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

41-255 power dissipation reality check
#1

I'm part way through the electrical restoration of a 41-255, fixing some previous old repairs, etc., and I see some indications of heat and possible arcing on the multi section Candohm style resistor (pic below) labeled 61 (33-3393) in the power supply section of the schematic (below). The resistance values are close to those listed but I'd like to replace it with discrete resistors, though I need a reality check on power dissipation (no info on the parts list or the 1942 Philco parts catalog...). I've sniffed here and over at the ARF but find varying information.

The filament string has its own winding so not a factor; the 84 rectifier is supposed to be good for ~60ma. Is it safe to assume worst case is 60ma through each section of that multi wire wound? For each section of ~150 ohms, 30 ohms, and 15 ohms, I come up with drops of ~ 9V, 1.8V, and .9V, so I figure dissipation of ~.54w, .1w, and .05w. I already have some 3w and 1 watt resistors on hand and figure that should be adequate. Just looking for a reality check here to make sure I'm not wildly underestimating what I need, since the original resistor seems like a huge overkill for that dissipation. Unless of course Philco just took advantage of what was on hand or perhaps it was easy to adjust the taps for any need, regardless if the required dissipation required was minimal.


Attached Files Image(s)
   
.pdf Rider-1942-PQR.pdf Size: 146.07 KB  Downloads: 184


Messages In This Thread
41-255 power dissipation reality check - by jtiner - 08-19-2022, 03:20 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
1949 Motorola 5A9M
This would be the second portable in the "other radios" forum where I have a similar one in my collection. I h...Arran — 12:41 AM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hi PittsburgTost. The record changer looks like a Garrard or BSR (Likely Garrard). The spindles just pull out and pu...MrFixr55 — 11:57 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hello PittsburghToast , Welcome aboard and it looks like gary may have something for you ! now if I dig through my se...radiorich — 11:35 PM
Model 80 Antenna Issue?
You are kind of on the right path. You can touch the grid cap of the Detector/Oscillator 36 tube. I'm expecting a respon...RodB — 08:48 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Welcome to the Phorum, PittsburghToast!  I found an old thread that my interest you regarding the quality and worth of P...GarySP — 08:48 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Welcome to the Phorum! :wave: We do not have anything on that unit in our digital library. There is a Sam's Photof...klondike98 — 08:47 PM
Model 80 Antenna Issue?
I’ve replaced all the caps and resistors and the radio is working but minimal volume unless I put my hand near the re...Hamilton — 08:24 PM
Looking for any info: 1977 Ford-Philco Console Hi-Fi Turntable and Radio
Hi there! this is my first time posting. I recently picked up this Ford-Philco Console record player and radio at a yard...PittsburghToast — 07:28 PM
philco predicta
I found that where I have the 140v B+ there is 50v and the tuner receives 235v through the orange cablecgl18 — 04:14 PM
Philco 91 code 221
Chassis grounds thru rivets is another good place to look. Oh and the stator screws on the tuning cap where the leads at...Radioroslyn — 08:11 AM

[-]
Who's Online
There are currently 311 online users. [Complete List]
» 1 Member(s) | 310 Guest(s)
Avatar

>