model 15 - Printable Version
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model 15 - madsowry - 01-28-2023
Hello all. Haven't posted in a while but I check this place out almost every night. I'm just starting on a model 15X. Some of the information I have has schematic changes with parts added and interchanged and some you have to know the run number. I checked the cabinet and there is no markings. How do find the run number for this chassis? Or do you just check to see if those components are installed. This chassis doesn't have the same resisters that the parts list calls for or the schematic that I have of which I have one from here and one from nostalgia air.
Thanks ahead for any info.
Dick
RE: model 15 - Brad Winder - 01-28-2023
Hi Dick,
I have a 15X as well; very nice sets, especially with the lighted grille lamp.
The run or "code" number, as Philco called it, was on the chassis label. Unfortunately, many of the labels have fallen off, due to the glue drying up. If your label is missing, you'll most likely have to figure out which version your 15 chassis is by the components. But remember that Philco, like most manufacturers, could have changed the odd thing during a run. They would not designate the chassis a different code unless major components or a change in the actual design took place. So, the odd component may not be in complete agreement with the schematics.
RE: model 15 - madsowry - 01-28-2023
Thank You Brad for responding. So I'm assuming I should just replace everything as the chassis is now assuming it is all original and it worked then. It does look like no one has been in this set. It looks virgin. Caps won't be a problem. Except for the electrolytics, everything is in Bakelite blocks. Resisters, if I read the color codes right, should be fine, too. Got lucky and all coils and transformers test out with good steady resistance, cold that is. We will see when they get some heat on them. Thanks again,
Dick
RE: model 15 - Brad Winder - 01-29-2023
You may find that the resistors start to drift pretty bad once they warm up, if they are the original dog-bone style of Philco resistor. But I find that some that I restore have perfectly good resistors, while others have drifted very badly. Seems to depend on the environment the set was stored in for all the years since it was last used.
RE: model 15 - madsowry - 01-29-2023
Thanks Brad. I was really curious with this radio today, it looked so untouched underneath that I had to see if it would play. I clipped in a couple new ecaps.
Then I checked the power transformer which checked out good. Then I plugged in the 80 rectifier and everything looked good. So I tested all the tubes and installed them and brought the radio up on my variac very slowly. At 90 v. it picked up one of the 2 local stations I get around here. I think that is amazing that a 91 yr. old radio can sit for how ever long and then get powered up and play. Amazing!!
RE: model 15 - madsowry - 01-30-2023
As I was saying in the last post, this thing is playing without changing anything but the electrolytics. Would you guys still change out all the Bakelite blocks and the filter condenser? Just wondering if the caps can still leak in the tar or wax, which ever they are in?
Thanks for any insight
Dick
RE: model 15 - David - 01-30-2023
If it was my set I would do a complete recap. Some info on reading resistor codes hope it helps. David https://philcoradio.com/phorum/showthread.php?tid=22425&pid=177816#pid177816
RE: model 15 - madsowry - 01-30-2023
Yeah David, I'm going to replace them all. I was just wondering what causes them to go bad since there is no moving parts and they are encapsulated.
RE: model 15 - David - 01-30-2023
Back in the day paper caps were nothing more than foil, wax paper for insulation a cardboard tube on the outside and a covering of wax. Just a little dampness and the cap starts to degrade.
RE: model 15 - Brad Winder - 01-30-2023
The short answer is that the paper inside turns acidic and that causes the cap to start allowing DC voltage through, basically like a resistor.
The long answer is that depending on what material the capacitor is built from, they all degraded at a different rate. Some manufacturers had issue within a year of manufacturing. Others had capacitors that lasted for many years with no issue. A good seal is crucial. But all paper capacitors degrade with time. The paper turns acidic, and the capacitor starts to leak DC voltages through. They become part capacitor, part resistor.
RE: model 15 - madsowry - 01-30-2023
Thank you Brad. That explains a lot to me. I was having trouble understanding the leakage. I kept thinking the cap would leak to ground or chassis. That's why I kept talking about encapsulation thinking it couldn't get to ground. NOT that it was leaking DC voltage through it. Your explanation clears it all up for me. Thank You
Dick
RE: model 15 - Brad Winder - 01-31-2023
No problem Dick,
Take one of the old paper capacitors apart and roll out the core. You'll see the layers and see how they were built.
RE: model 15 - madsowry - 01-31-2023
I have a little problem here. I'm recapping the tone control but mine is different than what's on the parts list. My tone control only has 2 caps. The schematic calls for 3 caps. Parts list calls for Pt# 04787. Mine is something, maybe 4 then 2-5001. Hard to read the first number. I studied bobanderson's restoration thread of his 15DX and his tone control was Pt.# 04787 and his connections were completely different from mine. His are all on the left side. Mine has 1 on the bottom left and 2 on the bottom right. I checked the Phorum library and the Philcobench and it is not listed in either one.
I guess it's not a real big problem if I just put it back the way it was but I don't know the values of the 2 caps. I'm guessing a .01 and a .02. That is what one is from 1933 according to Phorum parts.
Anybody have an idea if these values? Any info is greatly appreciated.
Thanks
Dick
RE: model 15 - admin - 01-31-2023
Moved to proper forum by admin.
RE: model 15 - madsowry - 01-31-2023
Sorry about having to move the thread. I thought since it was about a model 15 ,I should continue on the same thread.
Live and learn.
Dick