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[split] My 47-1230 Restoration - Printable Version

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[split] My 47-1230 Restoration - rstokes58 - 01-22-2021

Hello all , New to the forum and starting a 47-1230 restoration. The radio was my parents first piece of furniture they bought when he came back from the war (WWII). I have had it for 30 years or so and it was working until 10 years ago. Then the power transformer caught on fire, I put it out immediately with no other damage. Now I have the time and decided to try to get it working again. I ordered the replacement transformers and getting prepared to start. But trying to plan my strategy to approach this project. I don't want to dive in to deep and get in over my head, so: 

1st.    Do I need variac?
2nd    Should I replace the paper /wax caps before applying any power or just replace the power transformer and see what happens.

Im thinking the latter then replace the caps systematically. Any help or advise would be welcome.

Thanks fellow Philco enthusiasts

RE: [split] My 47-1230 Restoration - Nathan Slingerland - 01-22-2021

Welcome!

[Moderator note: I have split your post to its own thread since it is about a different radio than the original thread.]

RE: [split] My 47-1230 Restoration - Arran - 01-22-2021

The reason for the failure of the original power transformer should be investigated before applying power to the set again, it's very unusual for a Philco to suffer from a transformer failure for no reason. I would check for resistance between the B+ liine and chassis, as well as the tube filament wiring, including the pilot lamp sockets. More then likely it was a failed input filter capacitor, but you never know.
Regards
Arran

RE: [split] My 47-1230 Restoration - rstokes58 - 01-23-2021

Yes god points, flaming wax was dripping from the transformer, I assumed the transformer broke down internally but maybe touch much current draw from something else. B+ on secondary? 

Thanks

RE: [split] My 47-1230 Restoration - Radioroslyn - 01-23-2021

Like Arran said more than likely the input cap in the power supply shorted took out the the 5Y3 and the HV winding on the power transformer rendering it scrap.

Should I replace the paper /wax caps before applying any power
Good idea!

just replace the power transformer and see what happens.
Bad idea stock up on fire insurance.

Im thinking the latter then replace the caps systematically. Any help or advise would be welcome.
I would do it all at once.

RE: [split] My 47-1230 Restoration - rstokes58 - 01-24-2021

thanks for the advice

Im thinking the latter then replace the caps systematically. Any help or advice would be welcome.

I would do it all at once.

Has anyone compiled a list of the paper /wax caps for this radio?  Im assuming 500v rating?  electrolyte ? 

Thanks

RE: [split] My 47-1230 Restoration - RodB - 01-24-2021

I just had a look at the Nostalgia Air documentation. Generally, paper caps are identified visually and by value. Paper caps are usually tubular and have a black stripe on one end called the "outside foil". Values can be as low as .001mf (microfarads). You can buy the plastic film caps at 630 volts either from several sources here on the Forum or online from Mouser Electronics and others. When buying replacements for the electrolytics buy the 105° Japanese aluminum ones from Nichicon and others, or Illinois Capacitor. Modern capacitance values are slightly different from the originals, eg. .047mf vs .05mf. These will be sufficient replacements as the originals have a 20% tolerance.

RE: [split] My 47-1230 Restoration - mikethedruid - 01-24-2021

When replacing any condensers, always use new ones of AT LEAST the same voltage rating or higher. Higher is better. Use condensers of the same capacitance or as close as you can get. In power filtering circuits it is OK to go up to 1 1/2 times the original capacitance. Oh, by the way, I still call condensers by the old name, since I have been working with electronics since that was still the accepted term, although "capacitor", what most folks call them now, was beginning to be used. Yes, I am that old.

RE: [split] My 47-1230 Restoration - rstokes58 - 01-30-2021

So I am finally removing the power transformer and slowly id ing all the wires and trying to correlate to the new one. Radiodaze sent me two separate  transformers because there isn't one with HV ,FIL1 ,FIL2 and rectifier. the little xmfer is 6.4 v @.0.6A for the audio tubes , not sure which ones are the audio tubes???

Here is the old transformer 

thanks

RE: [split] My 47-1230 Restoration - Radioroslyn - 01-30-2021

That would be the 7af7 and 7x7.

RE: [split] My 47-1230 Restoration - rstokes58 - 01-30-2021

Thank  you radioroslyn, want to make sure I got my "wires  straight "  This is the secondary for those two audio tubes?
audio

RE: [split] My 47-1230 Restoration - rstokes58 - 01-30-2021

So, the Yellow leads HV, Black leads rectifier (F) , light blue Filliment 1, and red (H) Filiment 2 or audio , Green Center Tap ?

Thanks

RE: [split] My 47-1230 Restoration - Radioroslyn - 01-31-2021

Yes the heater winding with the grounded tap goes the the two audio tubes.
https://philcoradio.com/library/download/service%20info/yearbooks/1946-1947/split/Part30-Philco%20Home%20Radio%20Yearbook%201946-1947.pdf
Looks like your using a Sam's.

RE: [split] My 47-1230 Restoration - Radioroslyn - 01-31-2021

Have no idea. Philco uses a non standard color code on their transformers so your on your own.

RE: [split] My 47-1230 Restoration - rstokes58 - 02-01-2021

5ygt is the rectifier tube? So the rectifier tap of the secondary goes to that tube?

thanks