Radio Russ' Review of the General Electric P-780 AM-Only Radio

 

I've joined the ranks of collectors who have a General Electric P-780 with this recent acquisition from eBay. This is the version I wanted to wait for appearance-wise because I always liked the chrome carrying handle a little better than the fabric covered version. I also wanted the "Eight Transistor" legend instead of "Long Range." This is because I remember the marketing wars from that era where the number of transistors in the radio were the big selling point. This was pretty meaningless of course since there were some 12 transistor radios out there that couldn't measure up to the P-780 in any category. This marketing strategy raged for a while until a popular magazine of the time ran an article about a radio claiming 17 transistors. They crushed the transistors one by one with needle-nosed pliers with no change in the radio's performance. They got down to where there were only 6 transistors left and the radio still played on.

This P-780B is cleaning up very well so far but I have some work to do internally as well as externally. There is a heat related problem where the radio plays loud and clear for a few minutes and then drops over half its volume. Letting it cool repeats the cycle over again. I sprayed the output transistors with canned air and got the volume to return to normal so that's where I'm going to start. I hope today's transistors are of equal or better quality than the ones from over 50 years ago.

This radio is very clean and shows very little wear and tear. The dial light still works and De-Oxit took care of the crackling in the volume and tone control. This radio has what looks like a factory installed 1/4" headphone jack which I wasn't expecting to find.

As mentioned in other articles about these radios, it only consumes about 25 milliamps, so I believe it when they say a set of 6 D cells lasts for 800 hours. 

I got the P-780B for $36 and S/H which I consider a great price for its condition and relative rarity. The shipping was very reasonable considering that these radios must weigh in at 10 pounds or so. I'll let everyone know how I make out cleaning up the chrome grill and replacing the transistors.

 

Comments

[Stuart Morrison]

Congrats!

I bought a P-780e off eBay last August for $35 plus and it arrived with alkalines INSIDE, from MESA, Az. No leaks, I was lucky. It sounded good out of the box with a little scratchiness and dial tightness at the ends of the dial, nominally cleaned up well. You know about the radiointel.com 780 rebuild article, right? (http://radiointel.net/nostalgia-radio/restoring-serveral-ge-p780-am-portables/)

I paid for a re-cap kit from a regular eBay-advertiser, who didn't deliver, and the soured project was shelved until your wonderful pictures popped up. Keep us up-to-date, and if you re-cap (and you will eventually) let us know -- thanks!

Stu Morrison

[Angelo]

I have one and it's definitely one of my all-time favorite radios. I listen to the oldies station in Toronto, AM 740, on my old GE. It's like a time machine----life doesn't get much better. Mine had a somewhat muddy sound when I got it. I put new batteries in and the sound totally improved. Even though this is solid state, the deep resonant sound got me interested in looking for tube radios, and I've collected a few of those too.

[Huesby]

Russ:
Before you start changing the transistors verify that the current ones have or are connected to a cooling device because the symptoms you describe are normal for a transistor with NO cooling device attached to it and this is a way to protect itself.

[Radio Russ]

Huesby - I saw the protection circuit on the schematic. The heatsinks are on the output transistors like they should be. Since I get about 10 minutes before the volume goes down, I could be looking at a lot of different possibilities including a bad capacitor. Since it will happen even with the volume all the way down, it could be one of the front end transistors or support parts. I haven't really started yet but looking for those heatsinks was the first thing I checked. The plan is to get the malfunction to occur and then spray DustOff on each transistor to cool them and see which one causes the volume to come back up. Works like a charm, most of the time.

[Radio Russ]

Huesby - You were right about the heatsinks. I mistook the lampholder assemblies for heatsinks. TR7 and TR8 did not have heatsinks for some reason. TR7 was so hot it burned my finger! I made heatsinks from brass and used thermal paste and shrink tubing to make good contact and keep them in place. It's been playing at a pretty loud volume for over an hour since I installed the heatsinks. I think I will look for a couple of 2N1059 transistors just in case.

[Opcom]

I've owned a P-740F for >10 years and it became my favorite AM radio the first time I ever fired it up and remains so to this day. I always take it along when going on a picnic with a young lady. That great transformer coupled Germanium sound playing the AM Oldies is very pleasant. Ball games are easily heard by all. That radio commands respect, having plenty of volume for outdoors. Thanks for featuring it on the WWW, maybe I'll put up a pic. of mine too. Who's the lucky person that will see this other one at goodwill and jump on it before May 7, 2010 for $5? http://www.shopgoodwill.com/auctions/GE-P-780F-AM-Transistor-Radio-5898787.html (no connection to me, I just saw it and it deserves a home.)

[Brad]

Hi. I read elsewhere that the "Long Range" version of this radio (P-780H) had 9 transistors, supposedly making it slightly superior to models A through G.

[Ed S.]

Hi guys, I have a nice P-780B up for auction on ebay:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300558041496&ssPageName=STRK:MESELX:IT

[Joe Malinowski]

If anyone has a good to very good condition P780....any suffix or a P784 Musaphonic for sale please contact me at pa333@sbcglobal.net
I first saw these radio's within the last two weeks and bid on two of them on eBay with no luck (losing the bidding war in the last few seconds). I am not a collector but for some reason the face of these look awesome to me, a working one is a must!

Thanks!!
Joe
23 Dec. 2011

[G. Rabbitt]

Capacitors are probably the heating issue.. Just FYI, the headphone jack on the back is NOT original. None of the models ever came with one.

[Bob Johnson]

Anybody figured out why the volume drops after a few minutes on the GE P780?

[Pirate Bob]

I got one about 10 yrs ago, garage sale $10. My favorite porch radio. Batteries last a LONG time. Need volume knob, stem broke off. Also scratchy pot, reduced volume sometimes but still tunes well. Any help? Thanks