Welcome Guest! Be sure you know and follow the Phorum Rules before posting. Thank you and Enjoy! (January 12, 2025) x

Thread Closed

Philco 112 Lowboy restoration (caution, lots of images)
#15

Sorry for not posting this earlier!

The 112 is now completely restored and works quiet well.

After recapping I powered the radio up through a dim-bulb tester through 25, 40, 60, and 100 watt lightbulbs. Small amounts of audio came out with the 100W bulb and generally everything seemed like it was fine. Power up straight into the wall produced loud audio and tuning seemed to work fine.

Generally it worked pretty well. But there was clear audio distortion coming from somewhere. Lots of random poking around led me to look at the speaker drive signal on my scope. This showed pretty clearly that part of the waveform was very truncated. Somehow (I don't remember how...) I figured that one of the 45 audio tubes was bad. 45 tubes are annoyingly expensive because some audiophile people love them. So I ended up replacing both 45s with 1619s from here (http://www.dialcover.com/tubes.html). That completely solved the distortion problem. This problem also led to the only instance of electrocution in the project: when I foolishly decided to adjust the scope with one hand and the radio volume control with the other....ouch.

This is him all powered up (with the original 45s, one of which is blue):
[Image: http://farm3.static.flickr.com/2172/2399...a7_z_d.jpg]

And all put back together:
[Image: http://farm4.static.flickr.com/3049/2402...9a_z_d.jpg]

It currently has knobs from my (also now in restoration) 36-650. I need to find a source for the right knobs.

I use the radio about weekly. At power up there is a slight hum at about 3 seconds, and then audio comes through at about 15 seconds. It takes about 5-7 minutes before everything is entirely warmed up and stops drifting. I think there is slightly more hum than is supposed to be there. Also the volume control is annoyingly scratchy at the lower part of the range. It is a weird (to me) metal wheel in a carbon(?) sleeve affair. I've tried to clean it, but am afraid of harming it further. So I scrub it up and down every once in a while and live with it. Icon_smile

here is a picture of the volume control:

[Image: http://farm3.static.flickr.com/2220/2367...fe_z_d.jpg]


Messages In This Thread
[No subject] - by PhilcoPhil - 03-27-2008, 05:49 PM
[No subject] - by Ron Ramirez - 03-27-2008, 05:51 PM
[No subject] - by gary rabbitt - 04-06-2008, 01:32 PM
[No subject] - by BDM - 04-06-2008, 06:15 PM
[No subject] - by audin - 04-08-2008, 02:38 PM
[No subject] - by audin - 04-08-2008, 02:41 PM
[No subject] - by audin - 04-08-2008, 02:59 PM
Re: Philco 112 Lowboy restoration (caution, lots of images) - by audin - 01-08-2011, 09:57 PM



Users browsing this thread: 1 Guest(s)
[-]
Recent Posts
54C Complete Teardown/Rebuild
Hello Roy, here is this one sincerely Richardradiorich — 12:45 AM
54C Complete Teardown/Rebuild
Richard, Had grabbed it already but thank you just the same.  I find myself wanting to find some way to block out the...glyphmon — 12:03 AM
54C Complete Teardown/Rebuild
Hello roy, here is a link to the schematic . Sincerely Richardradiorich — 11:54 PM
54C Complete Teardown/Rebuild
Richard, The Silvertone 2014 also is a transformerless set, so I am incorporating a 1:1 600 ohm audio isolation transfo...glyphmon — 11:37 PM
Preliminary work on wife's Silvertone 2014
Did an alignment today which was interesting.  IF alignment went great, almost all was already spot-on.  Adjusting on th...glyphmon — 11:35 PM
54C Complete Teardown/Rebuild
The main problem with adding a Bluetooth input is that this set lacks a traditional power transformer to isolate it from...radiorich — 11:19 PM
54C Cabinet Refinish
I started stripping this cabinet before it got super chilly out because I knew I wasn't going to be able to work on ...glyphmon — 11:18 PM
54C Complete Teardown/Rebuild
While I'm waiting to wrap up the final steps on my wife's Silvertone 2014, I started disassembly on the next project.  O...glyphmon — 11:07 PM
Preliminary work on wife's Silvertone 2014
Hello roy, that great news glad it worked out for you !! Sincerely Richardradiorich — 10:50 PM
Preliminary work on wife's Silvertone 2014
Safety caps arrived today.  Soldered one in and had a successful first power-up.  No magic smoke escaped and it tunes in...glyphmon — 09:53 PM

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

>