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Philco 39-45 restoration: speaker wiring question and more
#16

Heat shrink tubing is just great for this. Use the same color as original if you can so you don't go nuts later hooking it up again.

Do open up the bells carefully and push the heat shrink tubing just as far as you can without disturbing the windings. You can take this opportunity to paint the bells if needed.
#17

codefox1 Wrote:Heat shrink tubing is just great for this. Use the same color as original if you can so you don't go nuts later hooking it up again.

Do open up the bells carefully and push the heat shrink tubing just as far as you can without disturbing the windings. You can take this opportunity to paint the bells if needed.

Thanks, that's good news because I've got the heat shrink tubing on hand already and can get started now. Will post some chassis pics in a day or two to help address some concerns..... looks like this thing has been worked on before I got it.
Have a good weekend.
#18

UPDATE:
Have been busy replacing/sleeving wires, caps including transformer and bakelite block. Basically working right to left under chassis. Trying to be careful and taking my time.
Things are going smooth and just about done, but ran into problems getting to some impossible to reach caps inside the coil assembly. To get to them, I need to unsolder around 15 or so wires, unscrew band selector arm and remove assembly frame. It will be extra tough to resolder a few wires that run through chassis holes to bottom of ganged tuner. Very short wires there! My head hurts thinking about screwing things up now, since I've gotten this far.
What do you guys do when you get to this part of recapping? Skip those caps or just do everything you can to get 'em out.... any tricks for tackling this section?
Thanks for reading this.
#19

Okay, I'll answer my own question:
Hey knucklehead, unscrew the protector plate, unsolder ground wire (copper braid) and pull straight out and you can get to everything on the coil assembly.

I was thinking the rods going through it were fastened to that plate, but the washers on each side are not attached so everything can slide between a notch I couldn't see.

Easier access to all but one cap and can fix more crumbling wires that were hidden now.
Stay tuned for more painfully idiotic adventures of me getting this thing up to snuff.
#20

Looks like you’re making a lot of progress. Not too long back I restored my 39-116 chassis. I rewired, recapped and changed all the resisters in the entire chassis. It was full of that rotten wiring your dealing with and a lot of it was so far gone I didn’t even want to try to use heat shrink on it. The band switch area is a royal pain in the butt but once your done with that area the rest is cake.

Here is a couple pics.

[Image: http://i1129.photobucket.com/albums/m501...AG0221.jpg]

[Image: http://i1129.photobucket.com/albums/m501...AG0223.jpg]

It is a very tedious job, but patience and a few beers and it will be done in no time. Coolest thing is when you’re done and you sit back and look at all the work you put into it and listen to it singing away.

Then like an idiot I went and got a 39-55 (little brother to the 39-116), so I get to start all over again with that rotten wire.. Icon_rolleyes

-Keith
#21

Hi Keith - Very good job on your '39!! I'm actually sitting on the fence about replacing some resistors.... noticed a toasty resistor coming off the grid of one of the power tubes so I measured it and was about 15% higher than specified. Those old carbon comps really drift, don't they? By the way, how did you deal with the oddball values when replacing?
I've read the mica caps don't usually need replacing, but I've got one installed in the pushbutton mechanism that's reading 460pf and should be 370pf. I'm thinking of replacing that one just in case.
Just need to replace wires coming from the volume pot and get the power tranny/bakelite block re-installed for a quick test. Will get some pics up soon with my results.
#22

RE the carbon comp resistors, cheap and easy to replace, makes a big difference when you finish up and align the set. Same with micas, never know how they will behave under operating conditions.
#23

greenskull Wrote:Those old carbon comps really drift, don't they? By the way, how did you deal with the oddball values when replacing?

I just got the value close, you got the 10-20% margin since the old carbon resistors were never really spot on for very long.

I didnt have to replace any of the mica caps in my 116, I just hit all the wax caps and the electrolitics

-Keith
#24

The mica caps in the pushbutton assemblies of those 1939-1942 Philcos are usually bad. Since they are only insulated with wax, they tend to absorb moisture over time.

370 pF is not a standard value any more, you can use 390 pF with no ill effects. Be sure you use new mica caps, or NP0 ceramics. Do not use regular ceramic caps as they will make the alignment of your pushbutton presets drift. Don't ask me how I know this...

--
Ron Ramirez
Ferdinand IN
#25

Ron Ramirez Wrote:The mica caps in the pushbutton assemblies of those 1939-1942 Philcos are usually bad. Since they are only insulated with wax, they tend to absorb moisture over time.
That's what I was thinking... definitely different than the other mica caps and not in a good way. I could not believe how bad that one looked when I pulled it loose to measure. Will replace.... looks like I'll be making another order out for parts.
Also will look into what I might need in resistors while I'm at it, just in case.
I'm sure I'll be posting for help when I get to the alignment.... would be nice to have one of those "station setters"!
Thanks everybody!
#26

Alright, here's the results after powering it up with about 50' of 22 gauge insulated hookup wire that I ran out the front door and up the nearest tree about 15':
All the lamps work now after using the washer inserted into socket trick located on this forum somewhere. That's great.
AM band works, but can only pick 3 stations and all but one is really noisey. Not too great.
International shortwave band picks up quite a few signals, but all are spanish. Well, it works so okay.
Police shortwave band cannot pick up any broadcast signal..... range may be obsolete?
Only one of the push buttons picks something up. That was expected.
I'm wondering if a better antenna (loop or ferrite core based) would get better AM reception?
Also noticed the grommets/washers attaching the push buttons/wheel controls assembly have crumbled badly.... does that assembly need to be absolutely isolated from main chassis to work the best?
When I compared the AM band of a new portable radio with whip antenna, the new radio could pick up a few more stations the console couldn't, but the reception was about the same on the ones they could both receive.
One last note: The power transformer started to make a buzzing sound after a few minutes... did not get hot just a little warm. The buzzing stopped when I pressed down on the top bell cover.
************************************************
I appreciate any thoughts anyone might have on the above.
#27

Okay I can answer on of the above questions I posted above. While taking out the grommets to measure for replacements, I noticed a ground wire soldered from the push button coil assembly to main chassis. Looks like the grommets are probably there to absorb shock and properly raise the height not isolate.

The bell cover screws were not fully tightened, so that may have caused the buzzing.... won't know for sure until I fire up again.

Still need to find out the appropriate antenna for this radio.... hopefully it will make a difference.

Stay tuned.....
#28

greenskull Wrote:Alright, here's the results after powering it up with about 50' of 22 gauge insulated hookup wire that I ran out the front door and up the nearest tree about 15':
All the lamps work now after using the washer inserted into socket trick located on this forum somewhere. That's great.
AM band works, but can only pick 3 stations and all but one is really noisey. Not too great.
International shortwave band picks up quite a few signals, but all are spanish. Well, it works so okay.
Police shortwave band cannot pick up any broadcast signal..... range may be obsolete?
Only one of the push buttons picks something up. That was expected.
I'm wondering if a better antenna (loop or ferrite core based) would get better AM reception?
Also noticed the grommets/washers attaching the push buttons/wheel controls assembly have crumbled badly.... does that assembly need to be absolutely isolated from main chassis to work the best?
When I compared the AM band of a new portable radio with whip antenna, the new radio could pick up a few more stations the console couldn't, but the reception was about the same on the ones they could both receive.
One last note: The power transformer started to make a buzzing sound after a few minutes... did not get hot just a little warm. The buzzing stopped when I pressed down on the top bell cover.
************************************************
I appreciate any thoughts anyone might have on the above.

My guess would be that the set probably needs an alignment, assuming that all of the drifted resitors and paper caps have been replaced. Other then that it could be a weak tube or a wiring error, but it probably needs an alignment. On the note about mica replacements I have used ceramic ones in some radios with no ill effects, I am pretty sure that they are precision rated ones, I wasn't aware that they made regular ceramic ones as small as 370 mmf or pf. Either way the ceramics are much cheaper then the silver mica ones, probably one tenth the price, not sure if they will work in all circuits, some TV circuits like vertical oscillators don't like the regular kind so you may have no choice.
In spite of the bad mouthing I like the 1939-42 Philco sets, they were decent perfomers and I like many of the cabinet styles. The fact that people don't like the rubber wiring and loctal tubes makes them all the more appealing to me.
Regards
Arran
#29

Thanks for the reply, Arran.
I was dreading having to go through the resistors and testing them all, so I might just cut to the chase and go ahead and replace all with modern carbon film type. I'm guessing 1/2 watt would do it for all? I would really like to test the tubes before even doing that, if possible. Someone has already changed a few and had to bend back the metal shield socket bases to get the new ones in wider pin bases) ... shields are missing too.

I'm learning as I go, so thanks for the patience. I mainly work with low voltage 9 volt battery stuff like guitar effects pedals, bat detectors, blah, blah. I dabbled with recapping and changing a power transformer in a radio a few years ago, but have not studied up on the workings of 'em since and am completely ignorant of alignment.... really have an excuse to get deeper into it now, which is good. Maybe I can find an old tube tester and RF signal generator for an affordable price in the near future.
I'll try to get some pics up next.
#30

Wow, it's been 3 months already! Here's some "after" pics as promised.
Will be getting replacement push buttons one day and one of those AM transmitters to hook up to a CD player, since there isn't much AM broadcasting my area.... 1 station comes in decent. Besides those things to do, I will need to paint the inside because the musty smell of this thing is a bit much at times (family complaints). Icon_rolleyes

I scored a BK RF signal generator at a Hamfest last month for $10 that I need to learn to help align this thing. I've been playing around with it and was able to get it to broadcast a CD player output to the radio, but fairly rough quality which had made think about looking into a proper AM transmitter.




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