Philco 296

[GuyIncognito]

Hello All!

I recently acquired a Philco model 296. It is pretty good shape and complete, except for (of course) one of the type 45 output tubes, and the small "Phono/Radio" indicator plate as seen in the photo in this link (bottom photo with the lid up--it is the leftmost control with the half-circle indicator plate):

http://www.radioatticarchives.com/radio.htm?radio=7901

Would anybody happen to have a better photo of this?

Thanks in advance!

[marty59]

That's pretty! And from the day when tracking force on that tonearm was measured in pounds!!

[PaulOF]

Oh that is beautiful. You probably know this, but you should give serious consideration to having the pickup rebuilt. The rubber hardens and loses compliance in those horseshoe pickups. As a result, the needle is not free to move and can damage the records it plays, as well as producing distortion.
Paul

[GuyIncognito]

Yessir! I fully intend to deal with that horseshoe pickup--once the usual obstacle of finding tinker time is dealt with.

I already printed up the instructions from the indispensable "Philco Phorum" the other day:

http://www.philcoradio.com/phpBB2/vi...php?f=3&t=1372

That missing plate is far more vexing than the missing (expensive) 45 tube. Of course, those tubes exist in some quantity, and there's always eBay or swap meets for securing one. I also have a supply of 1619 tubes (and dud 4-pin tubes from which to harvest bases), so creating a workable substitute is not a problem.

Remarkably, the two smallest knobs were with the set, along with the large tuning knob--but one of the medium sized knobs was missing at the time of pickup.

Once I got it home, I noticed that there was a curious rattling coming from the case (the chassis, speaker, and phonograph assembly had been removed for ease of transport). Investigating, I discovered the final "missing" knob in the record compartment at the bottom of the cabinet!

As you can probably guess, I broke out a flashlight and searched for that plate--no dice.

Who knows how many decades the knob languished down there, its only company being a sizable chip from an old 78?

There was also a gold-filled tie pin under the turntable (i.e. the actual platter).

[GuyIncognito]

While we're at it--and since the ad is still up--here are photos of the genuine article. The case is actually in extremely good, solid condition, and should benefit nicely from an application of Howard's.

http://detroit.craigslist.org/okl/atq/2056647981.html

It's presentable enough for the likes of me!

The chassis has a laughably thin layer of dust on it (not a speck of rust), and the tubes all check out. No further testing has been carried out as of yet

[holmesuser01]

Your radio is fantastic. I look forward to seeing it operating. You'll find a 45.

[GuyIncognito]

First, I would like to thank everybody who has offered help with or provided compliments for this radio--it is most sincerely appreciated.

I have kindly been provided a fine photograph of the "PHONO RADIO" plate by another VK member, and it is my plan to tweak it in a photo editing program in an attempt to create a mask for etching brass--one day...

I was FINALLY able to spend about an hour poking around with it yesterday. I was able to confirm continuity in the pickup after removing it, and even alligator-clipped the contacts to a small amplified MP3 speaker. Installing a steel needle and raking my thumb across the point produced a satisfying "ZIP!! ZIIIIP!!" in the speaker, so I am satisfied that it will be as good as new when I redo the rubber (probably after accumulated years of stolen moments).

I wanted to try powering it up using a dim bulb, as I am currently 3 and 1 when it comes to getting something in the way of operation from ancient Philcos using this method (before recapping).

However, I ran into a snag (guess I'm 3 and 2 now...) All of the wires going to the radio/phono switch are attached only as twisted splices. In point of fact, every wire associated with the pickup is only twisted on--not a spot of solder is to be found anywhere, from the pickup plug to the switch (about 8 connections). Was this how it left the factory?

Also, I am having trouble deciphering the schematic:

http://www.philcoradio.com/tech/images/296.jpg

I'm embarrassed to admit it, but part 54 (the phono/radio switch), as presented on the schematic, is utterly baffling to me. Can anybody explain its operation?

Please--if anybody can--remember to dumb it waaaaaay down

[Reece]

Hey, my head hurts. I looked and looked at that and then it hit me between the eyes. For that radio/phono switch, imagine that you are looking down on the terminals of an old double-pole double-throw porcelain-based Frankenstein knife switch. The two terminals in the middle are the knives which move in unison either up or down. For clarity (or so the Philco draftsman thought by not drawing the complicated wiring) terminal "G" connects to point "G" at the cathode of the third 27 tube from the right. "H" connects to "H" at the grid of the second 27 tube from the right. There is a diagonal connection from the lower left "G" terminal on the switch to the upper right.

When you throw the switch "down," the left-hand knife connects to "G" and the right-hand knife connects to "H." This is the "Phono" position.

When you throw the switch "up," the radio circuit is completed by the left-hand knife and the right-hand knife shorts out the pickup probably to avoid any stray hum pickup. This is the "Radio" position.

[GuyIncognito]

(cue Beethoven's "Ode to Joy")





By Jove, Sir--I think you've got it! NICELY DONE!!!!!!!!!

Just to clarify further, I have enclosed two images: first, of the original vexing section of the schematic; and second, a (busy) markup showing the connections of the "Frankenstein" switch. Is it correct?

Elegant--once you know the trick!

Many, many thanks!

[Reece]

That's it! Now, to untangle the wires....have fun!