Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
This 38-10 is the first Philco radio I ever restored back in 2006. I just did a basic recap and tacked the new electrolytics underneath. A few years later it died  and I'm just now getting around to taking a look.
[Image: https://farm4.staticflickr.com/3926/1463...5863_c.jpg]
Note I've already started doing work so there are some loose parts in this photo.
[Image: https://farm4.staticflickr.com/3903/1463...b506_c.jpg]
I figure while I'm at it I might as well restuff the filter caps too.
[Image: https://farm6.staticflickr.com/5578/1467...d4cb_c.jpg]
[Image: https://farm4.staticflickr.com/3882/1488...32da_c.jpg]
I finished up work under the chassis and powered it up. No smoke, but only a faint crackle output of the speaker.
[Image: https://farm4.staticflickr.com/3895/1492...a4e9_c.jpg]
[Image: https://farm6.staticflickr.com/5588/1474...d118_c.jpg]
Posts: 2,128
Threads: 18
Joined: Oct 2008
City: Merrick, Long Island, NY
Looks like you know what you are doing, ask here before plugging her in.
Posts: 599
Threads: 24
Joined: Jan 2014
City: Edmonton AB CA
Hey Bob:
You say it was redone and worked fine and then died a few years later, maybe a tube went south on you. Funny a working set that was recapped quit like that. I am sure you have done all the usual checks, B+, screwdriver on the volume control, throw some signal or IF at it??
Gregb
Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
I just finished checking all the tubes and they're all good. Touching the grid caps does produce hum. Next up voltage checks then I'll inject some signals.
Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
I found the problems  First, this resistor should be 51K but I installed a 5.1K. So hard to tell the red from orange sometimes!
[Image: https://farm6.staticflickr.com/5587/1493...5b06_c.jpg]
Second, a plate on the cap was bent on the far right and shorting for a portion of the rotation.
[Image: https://farm6.staticflickr.com/5560/1494...ec15_c.jpg]
(This post was last modified: 08-17-2014, 12:09 AM by Bob Andersen.)
Posts: 16,511
Threads: 572
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
Bob
1. None of this to me explains "worked a few years and then quit". What, has the vane bent all by itself? Or Did the resistor burn out or cause something to quit?
2. Whenever I replace resistors, even though I pull them from Mouser marked bag, I ALWAYS measure it bedore installing. I never read the code, why bother when you have a meter. Plus colors on all but beige/white are distorted.
3. What is that small yellow cap next to your open electrolytic? Is this what you are putting in? Looks too small for a main filter cap.
4. this blue electrolytic potted with green stuff: cannot claim 100% correct opinion but all light blue coated ones I ever saw are cheap GP caps and have ripple in low tens of mA. If it is a main filter one, not enough usually.
5. After I thougt awhile, I only pot the lead/bottom part and leave the barrel clear, the potting degrades temperature performance and this is what kills them faster. Especially main filter where ripple is high.
Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
1. No, it doesn't and we'll never know why the performance faded then died because I did a lot of work on this radio before powering it back up. That included replacing the three electrolytics, some tubes and all the resistors. The capacitor vanes likely were bent when I unmounted the tuning cap to replace the rubber shock mounts during this second restoration.
2. I think this may be a first for me after several decades of working in electronics both as an engineer and a restorer. I had been using blue bodied resistors and recently switch to the reddish types. Tough to tell orange from red.
3. It's a cap about to be thrown away that just got caught in the photo.
4. It's not potted and it's not blue. That's just some green bubble wrap to keep it from flopping around and some blue heat shrink tubing I put around it.
It's a PZ series Nichicon rated for long life, high ripple current and 105C. I only use top quality components.
5. I rarely pot anything and never a filter cap. Just makes it harder for the next guy to work on.
(This post was last modified: 08-17-2014, 02:16 PM by Bob Andersen.)
Posts: 264
Threads: 51
Joined: Aug 2014
City: San Antonio, TX
Bob! Good to see you on this forum. Having never seen one in the flesh or even in a photograph, I have to ask. Is that squashed funnel-like thing on the tuning cap a shadow meter? If it is, how does it work?
Posts: 16,511
Threads: 572
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
It is not the meter, it is a lamp.
As for the meter , it is a simple version of Darsonval/weston galvanometer (as in regular arrow analog meter) attached to a vane that shades the lamp behind it shining through a small opening. Depending on the current (in AVC circuit) the vane rotates making the shade narrow or wide.
Posts: 264
Threads: 51
Joined: Aug 2014
City: San Antonio, TX
Thanks, that makes sense. The Philco version of the tuning eye?
Charlie in San Antonio
Posts: 4,901
Threads: 54
Joined: Sep 2008
City: Sandwick, BC, CA
Shadow meters were not a feature exclusive to Philco, but they probably used more of them in more models, and used them for a longer length of time,
then anyone else, 1932-1938 if I remember correctly. They never did go with the magic eye tube idea, which was just as well, probably in part because RCA held some of the patents, the last thing that Philco would do is pay royalties to RCA if they did not have to.
Regards
Arran
Posts: 1,824
Threads: 114
Joined: Jul 2014
City: Sneedville, TN
I have an old Zenith model 411 from 1933 I restored years ago, complete re-cap. It has one of the electro-mechanical shadow meters. They are nifty and work as well as the magic eye tubes ever did.
Posts: 16,511
Threads: 572
Joined: Oct 2011
City: Jackson
State, Province, Country: NJ
...and they do not get dim. But then they can get demagnetized, or worse yet, the coil gets open.
Posts: 811
Threads: 43
Joined: Dec 2008
City: Chicago, IL
I finally found the time to do an alignment and put it back together. It's playing like new
[Image: https://farm6.staticflickr.com/5596/1489...5616_c.jpg]
Posts: 1,824
Threads: 114
Joined: Jul 2014
City: Sneedville, TN
Congratulations, Bob, absolutely beautiful ! I bet it sounds as good as it looks too.
Users browsing this thread: 1 Guest(s)
|
Recent Posts
|
Electrolytic restuffing/internals
|
Did as suggested. Cut can with hacksaw, removed internals, attached new 8mf cap - with ample use of cardboard and elec...bridkarl — 03:36 PM |
The list of my radio & TV collection!
|
For fans of antique radio...
My new video...
How to test radio tubes on a Hickok 530B tube tester?
Test radio tubes o...RadioSvit — 01:25 PM |
philcorepairbench.com - shadow-meter
|
Thank you
Billpoulsbobill — 11:53 AM |
philcorepairbench.com - shadow-meter
|
Hi, Try here
Philco Service Hints & Tips, Number 1
It's from the web archive (Way Back Machine).Keith — 10:17 AM |
PT-6 finished!!
|
Hi Arran,
Yes, you are correct, the "nominal" voltage for these Loctal tubes was the same 6.3 or 12.6 V as...MrFixr55 — 07:48 AM |
PT-6 finished!!
|
Actually the Loctal tube series, with number beginning with "14" are 12.6 volt tubes, at 150 ma, I'm not sure ...Arran — 02:14 AM |
philco predicta
|
The model is the holiday without UHF It has no sound and I don't have an oscilloscope or signal generator.cgl18 — 08:51 PM |
Philco model 38 code 121 not receiving signal.
|
I will definitely check my lead length and wire dressing. Thanks for the ideas.Stormlord5500 — 08:06 PM |
Philco model 38 code 121 not receiving signal.
|
Do make sure that you twist the 3 wires from the chassis to the transformer, and dress away from tubes, especially audio...MrFixr55 — 07:38 PM |
Philco model 38 code 121 not receiving signal.
|
The cone unfortunately got damaged when I removed it. The glue that held the cone to the basket was sloppily applied and...Stormlord5500 — 07:12 PM |
Who's Online
|
There are currently 876 online users. [Complete List] » 1 Member(s) | 875 Guest(s)
|
|
|

|