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
#5

Just an update for future reference... I've finished the electrical restoration of this radio and made some measurements (all with 122V AC line) in the power supply section. Overall current draw was ~395ma on the line side. The rectifier output measured 272V (vs 265) and 196V after the filters (vs 180). When measuring across my discrete replacements for the multi section R61, the 150 ohm resistor was dropping 9V, so about 60ma current as expected and just a tad over 1/2 watt. The 33 ohm resistor was similar, 2V, so about 65ma, .13w. When I removed the original multi section, I found that in addition to the apparent flash marks and scorching, the insulating paper was burned away over that same section of the resistor body.
So far performance seems good as far as I can tell using only the loop antenna in my basement (I was able to receive CHU Canada at 3.333MHz last night...). I've performed an alignment and ended up making a chassis solder connection to the riveted mounting plate/ground connection for compensating capacitors 17 and 17A. It appeared 17A was way too touchy mechanically, and soldering took care of that.
Also, regarding the failed pushbutton power switch, I attempted to replace the switch body with a similar one from Lowe's as detailed in a post here on the forum, but ultimately there was enough mechanical difference that the switch only operated correctly intermittently. That may be because of production changes to the switch available from Lowe's or perhaps I missed something. In any case, when I examined the original switch, I found it had failed because the wire lead on one side was never soldered to the copper contact in the switch. I soldered new leads to the contacts and re-installed the original switch. Instead of using epoxy to hold it in place, I soldered two sections of wire into the remaining sections of the original mount rivets so the rivets would stay in place and to act as a guide for sliding the switch body on. When the switch body was back in place, I twisted the wires to hold the switch in place. Some time later, I realized I should have cut the heads off small machine screws and soldered those into the rivets so I could put nuts/washers on, but hey...


Attached Files Image(s)
       


Messages In This Thread
RE: 41-255 power dissipation reality check - by jtiner - 08-28-2022, 11:11 AM



Users browsing this thread:
[-]
Recent Posts
Need to purchase some accessories for restoration of my Old Philco Radio
Hi Paulo, Welcome to the Philco Phorum. I can see why you want to find good reproduction parts. That is a bea...MrFixr55 — 11:10 PM
HiFi (Chifi) tube amp build - but my own design.
Tim, I have some bakelite sockets in my work shop that I can dig up. I believe quite a few are NOS. I will take photo...RodB — 10:03 PM
Philco 610B oscillator wiring
> The cathode as noted is wired directly to the ground side of the heater filament for that tube, not to the #17 and ...Radioroslyn — 08:12 PM
HiFi (Chifi) tube amp build - but my own design.
Tim; I noticed your post a little late, but I would take one of the junk sockets and try to break a chunk out of it wi...Arran — 08:07 PM
Need to purchase some accessories for restoration of my Old Philco Radio
Here is a list of resources found in our online library that you might find useful. Mike's Gobs of Knobs email addres...klondike98 — 01:46 PM
First Radio restoration
Hi Tubeman, Welcome to the Philco Phorum.  Phamily Phriendly Pfun with Phine Pholks Phull of Philco Phacts. (See a p...MrFixr55 — 12:33 PM
First Radio restoration
You could post in the WANTED ADs section here on the Phorum and see if anyone has an RF generator that they want to sell...klondike98 — 11:55 AM
Zenith H725
Good ideas, thank you Arrange and Rich. I have the adhesive aluminum foil already and can try that immediately. More ...EdHolland — 10:18 AM
Graphics for majestic 1050 dial glass.
Murf; I found this thread on the ARF, the first photo has a pretty good view of the dial glass. Regards ArranArran — 01:12 AM
Zenith H725
hello Ed, how about that speacial tape used for ducting it's like foil or how about thin piece of aluminum roof flash...radiorich — 12:19 AM

[-]
Who's Online
There are currently 1362 online users. [Complete List]
» 1 Member(s) | 1361 Guest(s)
Avatar

>