[Guest]

I just bought a Stand up Philco cabinet radio Model 39-31 I believe

In working condition! great shape. However I want to hook an ipod to it to listen to old radio shows. I don't want to Gut the thing as it is in great shape.. any way to do this without gutting it. I may get this dock for it.

[Image: http://www.vmart.pk/main/images/apple%20...20dock.jpg]

anyone?

[Ron Ramirez]

Hi

If your 39-31 is in good, restored, working condition, you can make a small modification to it to play your MP3 player through it.

Scroll down to the bottom of this page to see the circuit.

If it is a non-working radio...then you are in a bit of a dilemma, as the 39-31 speaker requires a source of high voltage to operate. This is an electrodynamic speaker, using a field coil instead of a permanent magnet. The field coil is tied into the radio's power supply and serves as a filter choke. When the radio is in operation, high voltage runs through the field coil, energizing it. This produces the magnetic field necessary to make the speaker work.

In short, you can't just connect your Ipod to a 39-31 speaker.

[jjbuzard]

My 41-296X has a 3 input pin jacks on the back of the chassis, I thought they were for plugging in an FM converter :
What is it for : Is that something you could plug a CD player into to play "old radio shows" :

[Music in a bottle]

Not certain, but I think my 70 has a sort of jack too, but unsure. Will be watching this thread real close!

[Ron Ramirez]

The three pin jack in the back of the 41-296 is for an external antenna. See this topic for more details:

http://www.philcoradio.com/phorum/showth...p?tid=1472

The Model 70, on the other hand, has no jacks for anything except for the 4-pin speaker jack.

[jjbuzard]

Ron,

The three pin jack in the back of the 41-296 is for an external antenna. See this topic for more details:
viewtopic.php?t=1926

Very interesting, I would like to connect my radio to a dead land line like you talked about in another post, I assume I would need a Philco Antenna Coupler, or make something like it. Did you ever come up with a schematic for this, and where would I buy the 3 pin connector :

[Guest]

use an am radio transmitter. you can plug your ipod into the transmitter then just tune in.

[philcoradio1234]

you could build a transmitter heres the link
http://sci-toys.com/scitoys/scitoys/radi...itter.html

[jepstr67]

There has to be a point between the tuner and the amplifier where we could add an 1/8" phono jack. I have the skills to do the surgery, but I don't know exactly what to do. I have a 38-40.

Todd

[Ron Ramirez]

Yes, there is - the top of the volume control. See the circuit at the bottom of this page.

[hollowstate]

Hi all:
I, too, have an ipod, but would rather hear my collection of vintage big bands... Anyway, many old signal generators make provision for external modulation, but whether the ipod would have enough oomph to bring it close to full modulation is another issue - might need a 12au7 amplifier, or even better a 6sn7 (schematic via google). Either way, I at first was concerned that the stereo outputs of the ipod might 'fight' each other if connected to a single point, but as long as the program is mono, that's not an issue - might still use a 2x8 ohm termination, though (at the price of ipods, I treat mine with kid gloves). Another advantage could be that if one did not previously own a sig gen for their bench, maybe this is good justification for it. Also, most of them have enough RF output to be heard at quite some distance.

[jepstr67]

Yes, there is - the top of the volume control. Did you see the link I posted above to a circuit on the Antique Radio Forum?

OK, yes I found a schematic by pbpix. He was talking about floating ground, standard chassis ground several other things that I don't understand yet. What does a 38-40 use? Also The Schematic looked different from the 38-40 Schematic you have posted(thank you). His is RCA? I'm sure to a trained radio repair man they all look basically alike but I'm in the early learning phase of radios. I'm hoping motivation to do this will add to my understanding of radios and their inner workings.

That, and the motivation caused by there only being one station I really want to listen to where I live. ;)

Todd
38-40K

[Ron Ramirez]

Okay Todd, when you said "I have the skills to do the surgery," I assumed you were well versed in reading and interpreting radio schematics. Obviously I assumed wrongly. (I've been told by more than one person to never assume anything...)

I do not have the 38-40 schematic posted on my website.

The 38-40 uses the chassis for ground.

If you have the 38-40 schematic, you would clip the lead labeled "Brown" which is at the top of the volume control. Then hook up the jack following the schematic which may be found at the bottom of this page.

[jepstr67]

Great! Thanks. That might get me by!

[Ron Ramirez]

I wasted this morning going to the town-wide yard sale...came back empty-handed...missed out on a free computer at one sale, then at another sale, I narrowly missed out on another Pentium III machine I could have bought for $10. Someone was buying it as I saw it. I was thinking about something cheap to feed MP3 tunes to an AM transmitter. Ah well, you snooze, you lose...

But anyway...

I decided to take some time and put together a partial schematic of the 38-40 showing the mod to add a 1/8" stereo jack (see below).

Full credit for this mod goes to Peter G. Balazsy, and is posted here with his permission. I only redrew a 38-40 schematic below to show how Peter's mod can be used on a 38-40.

[Image: https://philcoradio.com/images/phorum/Ph...840mod.jpg]