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capacitor question on a 46-200 transitone - Printable Version

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capacitor question on a 46-200 transitone - Paul D - 11-08-2011

Hi- I'm new to the forum. I actually called Ron R up about 10 years ago when I restored my last Philco (a model 87 Neutrodyne). Well I'm back at it again and am now working on a model 46-200, a 48-250 and a 48-1270 that I picked up at my local thrift store for $40 in unbelievable condition (exterior-wise).

Anyways, my apologies if I am asking a common question, but I want to replace all the capacitors in the 46-200 transitone. The ones for the audio circuit are pretty straightforward, but I am having trouble finding electrolytics for the power circuit. The ones on my chassis (which unfortunately are original, but do not match the schematic) are the following:

1) a .2uF 400V Sprague capacitor that has the wire from one end wound around it about 8 times or so (for which reason I don't know but am planning to replicate)
2) a .04uF 400V philco cap (part number 30-4119)
3) a dual cap (20uF-20uF) 150DCWV that may still be good (which is different than what is shown on the schematic which is a 30-25-30)

I went to Antique Electronic supply (where I usually get my parts) and they don't have electrolytics at those small values.

can you please advise what I should do? I figure whatever I do for this one I will probably run into with the next two units.

Thanks so much in advance!
Paul

Re: capacitor question on a 46-200 transitone - Texasrocker - 11-08-2011

Welcome! Dave has a much better selection of hard to find Capacitors at his website:
http://www.justradios.com He is located in Canada, so pay for the "fastest airmail" option if you are in a hurry to get all your new capacitors. Check your schematic closer also, and make sure you order the correct replacements. Always observe polarity and voltage ratings according to original schematics when replacing capacitors. Use higher voltage ratings than originals called for when using modern replacement caps. When sets have been previously "hacked", no telling what someone used in the past. Most likely something they had on hand. Best of luck restoring your vintage Philco!!

Re: capacitor question on a 46-200 transitone - codefox1 - 11-08-2011

Don't worry about the funny capacitor with windings around it. There were marine radio beacons decades ago that were close to the IF frequency that caused problems at times , long obsolete. Just sub a modern equivalent and skip the windings.

Re: capacitor question on a 46-200 transitone - Paul D - 11-08-2011

Thanks for the tips- I'll check out the Canadian site tomorrow. I would like to use electrolytics for these capacitors as they are on the power circuit- I am just surprised that they are such low values...

Re: capacitor question on a 46-200 transitone - Paul D - 11-09-2011

no dice on the Canadian site- the values are too low- thanks for the try though! Here's a pic of one of the capacitors- maybe I can get away with using a different type? This one is the largest one size-wise in the chassis

Thanks again for the feedback- Paul

Re: capacitor question on a 46-200 transitone - Arran - 11-10-2011

The values of .04 and .2 mf would normally be replaced with polyester film capacitors, roughly the modern equivalents of the old paper caps not with electrolytic capacitors, I don't think that you could even buy a .04 mf electrolytic off the shelf. The closest stardard sizes to a .04 and a .2 mf would be a .047 and a .22 mf at either 400 or 630 volts, Radio Daze and Bobs Antique Radios cary these sizes. The electrolytic filter caps you list can be purchased through these two outfits or from Mauser Electronics as single caps, the values in microfarads are not very critical so long as they are the same size or larger. The 20-20 150 volt unit in there was likely a replacement, you can use a 30-30, a 40-40 or a 50-50 etc, but most people don't use two or three section filter caps anymore they install single filter caps in it's place as the selection of ready made units is limited. What some do is to take two or three singles, clean out the case of the old two or three section unit, and stuff the new ones inside if they can find ones that fit.
Regards
Arran

P.S you can recreate the old .2 mf and choke unit if you wish fairly easily, you remvove the old unit, unwind that small coil keeping count of the number of turns of wire, melt ot the innards of the old cap, install a new .22 mf inside, and then rewind the coil on the shell of the old paper capacitor.

Re: capacitor question on a 46-200 transitone - Paul D - 11-12-2011

update:

good news is that I got the radio running and it sounded great! bad news is that it quit after about 30 seconds and appears to have blown the rectifier tube. Everything quit at once (all the tubes dimmed at the same time the light bulb dimmed.

The challenge is that the schematic that i found online for a 46-200 does not match my radio which is a 46-200 code 121. They must have made a few changes as the tubes are different (my tubes match the tube label on the bottom of the case, the power cap is a 20-20 (which I replaced with electrolytics) versus a 30-25-20, and the schematic itself is quite different from how my radio is wired. It had all philco components when I got it, so my guess is that Philco must have done a few updates....

So at this point I need to figure out what took the rectifier tube out. I am going to look for a different schematic (if you have any ideas, please let me know), but I figure there's more than a couple of you that have run into this before, so any advice is sincerely appreciated!

I replaced all the audio caps with polypropolyene caps of equal value and of equal or greater voltage rating. The electrolytics are wired correctly I have checked for shorts and I can't find any. Nothing smells burnt or melted. It may just be a bad tube, but I am pretty doubtful (however that would be a nice solution as I have to get another one anyways). Not sure how to check the tubes but an old friend of mine has a tube tester I am going to try to steal this weekend.

Thanks again in advance for the advice!

Paul

Re: capacitor question on a 46-200 transitone - Ron Ramirez - 11-12-2011

I would start by buying the service information package for your set from Chuck.

http://www.philcorepairbench.com/schematics.htm

He will send you an oversize copy of the schematic as well as all service notes including known production changes. All for $7, what a deal!

Re: capacitor question on a 46-200 transitone - Paul D - 11-12-2011

Thanks Ron!

Re: capacitor question on a 46-200 transitone - Paul D - 11-27-2011

Update- I may be getting closer. I received the great schematics from Chuck and dove back in for another round. The filament on the incandescent lamp was shot as well. So I replaced it with a #47 (which is as close to the spec as I can find....although I may want to try a 12V bulb instead of the 6v one....) and checked all interconnects, etc.

I fired it up- as son as the rectifier tube (my last good one!) started to operate, the pilot/incandescent lamp got waaaaay bright. So I shut it down fast. My guess is that this is how the last two rectifier tubes died... so I am now scratching my head as to why this is occurring? I thought that the rectified power circuit and the circuit for the heater elements for the tubes was pretty much independent, but I guess I am wrong.

Maybe I have a bad replacement cap? Anyways, It may just be that I am putting the wrong pilot lamp bulb in, but I don't think so....


In any case- thanks to you all for the help and I will keep fiddling with it!

Paul

Re: capacitor question on a 46-200 transitone - Paul D - 11-27-2011

So I guess all I needed was your moral support guys! I just went back to the radio and noticed that the super-genius that I am installed the main capacitors (the only ones that I have that are polarized) backwards! So... essentially as soon as the rectiver circuit came to life, the caps shorted and took the tube which took the filament which took the pilot light out.....

Anyways, I can't be happier that you all have been such a help. I have had the set on for about 2min and am going through all the test points in the documents that Chuck sent me.

I'll send an update and pics when (hopefully) I finish testing and re-assembly!

Re: capacitor question on a 46-200 transitone - Paul D - 11-27-2011

1 hour running great! Thanks again to all.

Re: capacitor question on a 46-200 transitone - morzh - 11-27-2011

Paul D Wrote:I just went back to the radio and noticed that the super-genius that I am installed the main capacitors (the only ones that I have that are polarized) backwards!

If I only told you how many time I received my boards built with half the electrolytic caps installed backwards by some very reputable prototype assembly houses.....and they are supposed to be the pros.

So, congrats.

Re: capacitor question on a 46-200 transitone - codefox1 - 11-27-2011

We've all done it at least once. Kind of like zippers. You remember to check.

Now then, don't toss the rectifiers if only the pilot bulb portion of the filament is gone. You may need them sometime, and your 35 volt rectifier is not a 32 volter, and you'll have to do something else for a pilot light, lots of options there.

Re: capacitor question on a 46-200 transitone - Paul D - 11-28-2011

Thanks- I've saved the bulbs as they still tested out good on my tube tester