FStephenMasek's Philco 112 chassis restoration
Posts: 234
Threads: 43
Joined: Mar 2008
City: Mission Viejo, CA
I found this one just a few miles from our house. Unfortunately, the top veneer had been destroyed by a house plant, and somebody had hacked-in a cheap PM speaker. It was sold as non-working. Somebody had also-hacked-in new capacitors without disconnecting the old ones in the bakelite blocks.
[Image: http://i269.photobucket.com/albums/jj77/...0found.jpg]
The wirewound resistor was bad. After I replaced it, I think I found the problem at one terminal, but the nice new replacement is in place. [Image: http://i269.photobucket.com/albums/jj77/...sistor.jpg]
I disconnected and labeled the wires to the capacitor black can. Somebody had soldered a terminal strip to one of the positions for the junction of two resistors, so I eliminated it. Be careful, the numbered terminal positions of the schematic and those in the under-chassis pictorial diagram do not match, except that terminal #4 is the same on both. I mounted a terminal strip to hold the new 6.8 MFD electrolytic capacitors under the former position of the long-gone can capacitors. I also mounted a fuse holder, as it seems like a good idea to have a fuse on any radios with a power transformer.
[Image: http://i269.photobucket.com/albums/jj77/...marked.jpg]
The can came apart with ease. The metal ring was just pressed onto the end of the can.
[Image: http://i269.photobucket.com/albums/jj77/...20open.jpg]
The terminal board with the new capacitors soldered to the appropriate terminals. I only had one 0.47 capacitor in my stock, so made the other two replacements for the 0.5MFD units by paralleling 0.22 and 0.3 MFD capacitors.
[Image: http://i269.photobucket.com/albums/jj77/...%20can.jpg]
The power switch tested as open. I removed it and sprayed some contact cleaner into the gaps, then worked the switch.
[Image: http://i269.photobucket.com/albums/jj77/...switch.jpg]
This is an easy to restore chassis. I simply had to unsolder four wires and clip the dial light wires, then remove five screws to remove the gang capacitor assembly, complete with the drive mechanism. This will make cleaning and painting the chassis much easier.
[Image: http://i269.photobucket.com/albums/jj77/...emoved.jpg]
(This post was last modified: 05-17-2017, 10:55 AM by FStephenMasek.)
Posts: 234
Threads: 43
Joined: Mar 2008
City: Mission Viejo, CA
I hesitated before disassembling the tuning gang, but that is the best way to paint the housing, and it was easy to dismantle:
[Image: http://i269.photobucket.com/albums/jj77/...embled.jpg]
I used abrasives and Naval Jelley, then the chrome paint I think I first used on the chassis for our Crosley grandfather clock radio. I ran out of daylight and energy, so the base chassis still needs to be cleaned.
[Image: http://i269.photobucket.com/albums/jj77/...ainted.jpg]
I also had time to clean and paint the chassis. It looks so good that I may just leave the transformers and choke chrome, rather than going over them with black. I cleaned and painted the aluminum cans, as they were also corroded.
[Image: http://i269.photobucket.com/albums/jj77/...filled.jpg]
Now, she is playing. I need pereform the alignment. The dial is off, and changing the 600 padded does not make much difference.
The tone is best with the control set so that none of the capacitors are in circuit, and is the same for the last two settings. Therefore, I will replace all three capacitors with much smaller value units.
Posts: 13,776
Threads: 580
Joined: Sep 2005
City: Ferdinand
State, Province, Country: Indiana
Stephen, I hope you do not mind that I split the chassis portion of your 112 thread into its own thread here in Philco Electronic Restoration.
You can still find the 112 cabinet thread here in Philco Cabinet Restoration.
Great work so far on chassis and cabinet.
--
Ron Ramirez
Ferdinand IN
Posts: 234
Threads: 43
Joined: Mar 2008
City: Mission Viejo, CA
That Ace chrome paint certainly worked well on this chassis:
[Image: http://i269.photobucket.com/albums/jj77/...nsihed.jpg]
Yes, I dismantled the tuning gang capacitor to paint the housing.
[Image: http://i269.photobucket.com/albums/jj77/...nished.jpg]
I replaced all of the resistors and all except the mica capacitors. Some of the Philco capacitor blocks had been damaged by the hack who had previously worked on it, so I replaced them with terminal strips:
[Image: http://i269.photobucket.com/albums/jj77/...nished.jpg]
This chassis has a bottom, as it sits on two horizontal boards, not a shelf
[Image: http://i269.photobucket.com/albums/jj77/...nished.jpg]
(This post was last modified: 06-04-2017, 03:36 PM by FStephenMasek.)
Posts: 234
Threads: 43
Joined: Mar 2008
City: Mission Viejo, CA
Any ideas ? It is playing up and down the dial, but with low volume. Please consider the following facts:
1) the voltages at the tube sockets all look good, perhaps a bit high (e.g. 187 on the plate of the 1st RF tube, 275 on the plates of the '47 tubes);
2) Both '47 tubes are good and test the same
3) All of the other tubes have been tested and are at or above the reading showing on the roll chart of my Hickok
4) The plate voltage at the 1st Audio Tube is just 89. Bypassing Resistor Number 46 increases it to 138V, but with no increase in volume.
5) Jumping the volume control makes no difference from setting the volume control at maximum
6) All fixed capacitors, except a few mica units which test properly, were replaced
7) The audio inter-stage transformer primary measures something in the 4.5K range, and the secondary something like 5.5K ohms.
It took me too long to finally determine that one of the capacitors numbered 25 on the schematic was missing. It only worked at the low end of the dial, and RF alignment was impossible. Both number 25 were originally metal cans, long gone from this chassis.
By the way, the schematic notes that there are two capacitors numbered 34, but that is incorrect.
Posts: 1,475
Threads: 69
Joined: Nov 2012
City: Kansas city, MO.
Nice job on the chassis. On the #34 capacitor. The last page on NA site shows a part # 34 as Bypass condenser .5 MFD. Two used. This is for chassis with serial # above 174,001.
Posts: 234
Threads: 43
Joined: Mar 2008
City: Mission Viejo, CA
The secondary of the third IF transformer was open! Fortunately, I had a NOS Philco 45-6365 Universal IF Transformer in stock, so installed it. It now works properly.
The finished chassis bottom, with the cover off
[Image: http://i269.photobucket.com/albums/jj77/...nished.jpg]
Detail of the new IF transformer. Since the new transformer has internal trimmers, I removed the original trimmer for the 3rd IF primary.
[Image: http://i269.photobucket.com/albums/jj77/...d%20IF.jpg]
The new transformer atop the chassis. This is probably exactly the repair which would have been made if somebody had taken this radio to a Philco repair shop a few decades ago.
[Image: http://i269.photobucket.com/albums/jj77/...d%20IF.jpg]
The old IF transformer. Both wires to the secondary looked good, and I did not see any external signs of distress, although a spider had lived there.
[Image: http://i269.photobucket.com/albums/jj77/...d%20IF.jpg]
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Cannot Adjust an IF Transformer’s cores
|
Outstanding work indeed. I wish I could come up with solutions like this.slford310 — 11:16 PM |
Cannot Adjust an IF Transformer’s cores
|
The abilities of our 'Phorum Pholks" never ceases to amaze me! Fantastic fabrication, Joseph! I'm waiting now for...GarySP — 08:27 PM |
PT-6 antenna connections
|
Thanks. I never realized that was a notch noted in the schematic as described. I’ll recheck my wiring.bridkarl — 08:13 PM |
Cannot Adjust an IF Transformer’s cores
|
Thank you! I was quite new to the Phorum when I started this post, so I feel like it might be advantageous to publish a ...jrblasde — 08:07 PM |
PT-6 antenna connections
|
Notice in the schematic the notch at the bottom of the antenna coil is between pins 3 & 4.
Yes, pin 6 of the 7C6 is...RodB — 07:34 PM |
bridkarl
|
I have two PT-6 chassis. On both there is a blue wire that runs from the above chassis transformer to pin 6 of 7C6. So t...bridkarl — 07:23 PM |
Cannot Adjust an IF Transformer’s cores
|
Joseph, now you are an engineer!!RodB — 06:37 PM |
PT-6 antenna connections
|
Hi, reading your explanation I can see the confusion. If you take it one connection at a time it should result in a desi...RodB — 06:34 PM |
Cannot Adjust an IF Transformer’s cores
|
It works! I received the PCBs this morning in the mail, and put everything together. I reused the base from the original...jrblasde — 04:32 PM |
PT-6 antenna connections
|
I seem to have lost my way on this PT-6.
I see the antenna aerial transformer schematic - I’m reading pins 1 through ...bridkarl — 12:30 PM |
Who's Online
|
There are currently no members online. |
|
![>](https://philcoradio.com/phorum/images/bootbb/asb/right_arrow.png)
|