[Mountaineer]

Hi Everyone!

Last week, I acquired a Philco 41-250 that appears to be in decent shape considering its age.  I pulled out the chassis and I have started cleaning it.  I have some experience in repairing antique radios -- I have successfully repaired about 5 or 6 AA5 radios, but those were pretty simple jobs.  However, I have not had much success with transformer sets like this 41-250, so any advice will be much appreciated!

First of all, other than the usual re-capping and replacement of worn out wires, is there anything in particular I should look out for on this particular radio?  The underside of the chassis looks very clean -- the only thing I've noticed is it looks like the filter caps were replaced at some point a long time ago.

Secondly, after I took a good look around, I decided to power up the radio using a variac and a current meter.  I know many advise against this, but I wanted to see what I had before I started tearing things apart   . The pilot lights all lit up very well, but it seemed as if the filaments on the tubes were weak.  The filament on the rectifier was lit but dim and one of the two output tubes got hot after the radio was on for about 2 or 3 minutes.  Also, I got no sound out of the speaker other than some very very faint hum -- not the kind of hum associated with bad filter caps.  The bandswitch was in the AM broadcast position.  What are the most likely reasons why the radio seems dead?

I have ordered replacement caps and will begin digging into this radio in earnest next week.  I know I will have lots and lots of questions!  Many thanks in advance for any advice or recommendations you guys have.  I look forward to sharing this restoration experience with everyone!

Best regards,

Jason

[morzh]

The procedure is the same for AA5 or anything else, just the scope of the project is a tad bigger.

Same thing: recap first.

Also: 1941 radio might have the rubber insulation on the wires cracking: if you see any of that, replace the affected wiring. In my case, 41-280, all wires were fine.

Now that you have a transformer, without any tubes measure the output and confirm the transformer is good before you commit, unless you are willing to proceed even if it is bad.
Without the rectifier tube but with the rest of them in measure the voltages across the filaments, confirm they are ok.

Then proceed as usual: after recap, rectifier tube in, measure voltages etc.

[Electrothaumaturgist]

Don't forget to hook up the speaker and antenna (if provided) when you install the rectifier tube...

[Hot Rod]

My first resto attempt was a 41-295 console.  I re-capped and then got lucky stumbled across the open output trans .  I ordered the closest thing I could find at http://tubesandmore.com/.  It bolted right in.  When it lit up and played for the first time I was almost in tears!  It's ALIVE!!!  

So I don't know for sure if yours has an output trans but the chassis looks similar.  Worth checking before you power it up again. 

I don't remember rubber wires on that one.

Good Luck!!!

[klondike98]

Welcome to the Phorum!

[Hot Rod]

I added a headphone jack to the volume control so she could play her ipad through it and gave it to my daughter.  It's now her daily player.  Not bad for my first try.

[Mountaineer]

Hi Everyone!

Thanks to everyone for the advice and encouragement! But I do have a couple quick questions. Morzh suggested that I pull the tubes and measure the filaments. What should the voltages be on the filaments? Also, Morzh suggested I pull out just the rectifier and measure the transformer output. Where do I take this measurement? At the plate pins of the rectifier? And what should these voltages be? I do understand that these would be AC voltages but I'm still kind of new in terms of working on transformer sets. Thanks again for all of the help!!

Best,

Jason

[Radioroslyn]

So probably a good place to start is a legible schematic. You can find it here:   http://www.audiophool.com/Philco.html  The Rider's stinks for this set. The 84 tube is the rectifier and with the tube removed you should see about 500vac from pins 2 and 3. Across 1 and 5 about 6.3vac.

[morzh]

Measuring "across the filaments" means just that - measuring across the filaments. At the respective pins of the tubes.
For example, in the 41 tube, those are pins 1&6. Since all tubes are in parallel, measuring at any tube's filament will do.
This will ensure that the transformer in question powers the filaments to the expected voltage.

[Mountaineer]

Hi Everyone,

I just wanted to let everyone know that I've been able to bring the 41-250 back to life!  I finished re-capping it last night along with a few other things and much to my surprise it played. It works very well on the AM and shortwave bands.  The push-button tuning doesn't seem to be working --  my guess is that all the coils associated with those need to be re-tuned and I don't have the equipment to do that.  But that is something I can live with as I didn't really intend on using those.  Thanks again for everyone's advice, especially to Terry who walked me through the testing of the power transformer, something I had never done before but now I understand how to do it! 

Best wishes!

Jason

[klondike98]

[Hot Rod]

Congrats!!! Great job!

Those push buttons are available.  The repo's that I have on my 41-255 look really nice, but not exactly like the originals.  If I remember, the originals are dimpled, the repo's are convex.  Only you will notice (that's what my wife keeps telling me).   BTW, I bought my 255 already restored.  Not nearly as rewarding. 

So post a picture and share with us.