Rare REED-TYPE Speaker in a 1964 Transistor Radio RESURRECTION - GE P807J [4K]

Let's take a look at this rare reed-type speaker in this 60 year old transistor radio. This type of speaker was mainly used upwards of 100 years ago in the horn speaker days, but GE did use this design in some radios in the early 60s. The reed speaker was known for its efficiency with power requirements, and due to the impedance of the coil that powers it, it does not require an output transformer. It can run quite well being driven by a single transistor as a Class A amplifier.
Unfortunately, this little radio does not work. Let's see if we can bring it back to life, and hear how this interesting speaker design actually sounds.
See the checklist which appears when status changes, for tracking what is discovered that needs addressing in Red, followed by Green when resolved.
NOTE: This is not instruction, it is for entertainment for people like me who enjoy watching projects and the experiences gained. If you attempt to do any of the things in this video you are at your own risk. I am using special tech-bench safety equipment not detailed here so don't take for granted you can just plug these old items in safely without them being checked and repaired correctly. Check out the link below to Mr Carlson's Lab video below.
ACKNOWLEDGEMENTS AND REFERENCES:
[note: am in no way representing how these folks have shown doing these things - I don't even think they would approve.]
Thanks again to Tony at xraytonyb for a great way to attach an inexpensive frequency counter to a signal generator and power it from the generator as well. • Tenma Signal Generator...
‪@xraytonyb‬
Thanks to shango066 for championing the approach of "fix it first", before mass re-capping. See shango066 for many examples of that approach.
@shango066
Awesome discussion of bench safety including variacs and isolation transformers by Mr Carlson's Lab (highly recommended):
• Tech Tips Tuesday, Iso...
‪@MrCarlsonsLab‬
Modification method for a commercial Tripp Lite isolation transformer for tech-bench use by Todd Harrison, his channel is called ToddFun:
• ToddFun.com: Isolation...
‪@ToddFun‬
People who may enjoy this video will interested in: portable transistor radio, General Electric transistor radio, 1960s radio, radio repair, radio troubleshooting, capacitor wizard meter, old radios, AM radios
Camera: Canon G7X Mark III
Mic: Rode Micro
Video Editing Software: Power Director
Video Editor: just me

Wonderful video!!! I am. an old engineer from the
50's and serviced many valvular and transistor equipments. I like to learn more thanks to you. Gracias Patagonia Argentina.

[@PracticallyFixed]

Hello, it is good to meet another engineer. Thanks for the kind comment.

[@teasea3152]

I have that same radio. It's a model P807C. I think it's a earlier version than yours because it has the triangle Conelrad markings at 640 kc and 1240 kc on the tuning dial. Like yours, It has the pin drive speaker. It originally used the larger, expensive, almost unobtainable 9 volt battery that had a larger battery connector instead of the common 9 volt battery of today. I converted it to use 6 AA bateries in a holder that fits perfectly into the battery space inside the radio. Other than the battery modification, it has all of the original components and still works very well although the sound quality is more tinny than that of a permanent magnet speaker.

[@PracticallyFixed]

That's interesting about the other model. For broadcast AM voice, which is nearly all we get anymore, the tone works well I think. The larger 9V battery seems to have been the other change. I am still not sure that capacitor which I thought may have been a '63 date code was actually original. Solder looked factory for it however. Thanks for the comment.

[@daleburrell6273]

...I have one of those radios with the reed speaker: it had low, distorted sound, and I finally noticed that the ferrite magnets on the speaker had disintegrated.

[@jimnewman5596]

That reed type speaker sounds good. Great find and repair of that nice little radio.

[@PracticallyFixed]

Thanks. It was nice to have a simple repair for a change. A one-part video!

[@elmofeneken4364]

Really enjoyed watching you fix this old GE radio. Learned a thing or two along the way. Nice work.

[@PracticallyFixed]

Hi Elmo, thanks for the kind comment. I like fixing stuff and I always learn something along the way. Thanks again.

[@ianallen2]

For mixing epoxy glue, use the plastic lids from butter / margerine / sunflower spread tubs. No card or paper to soak some up and the hardened left overs can be peeled off when set, making hte lid re-useable. :).

[@PracticallyFixed]

Great tip! Thanks for the comment and for watching.

[@ianallen2]

@@PracticallyFixed Youre welcome. First time I saw your chanel. Just subscribed. :). Looking forward to watching more. I also watch Mr Carlsons Lab and Shango. All the best from UK.

[@PracticallyFixed]

Thanks for the sub from Texas! Cheers

[@jamesatkinson6480]

At the time, Japan was very busy making these, and I think after the 'Regency TR - 1', the USA made several (now very collectable) variations, using a 'transformerless' class A output stage. In Australia, the large brands who made tube (valve) radios used some of the hardware (metal chassis, IF transformers, ferrite core antennas) in their transistor radio production, where import tariffs were heavy with an equivalent Japanese product. What I see as wonderful is how, after all this time, with the same test equipment, you can restore a transistor radio without replacing any active (semiconductors) components...

[@PracticallyFixed]

G'day and howdy from Texas, James. It is rather amazing those transistors are still in there happily semi-conducting. Not bad for only one bad component after 60 years, and just an electrolytic capacitor. I have reasonably good luck with many old valves (tubes) as well as long as the audio grid coupling cap hasn't begun leaking and fry the output valve and the output transformer. Did repairs on a couple of 70 year old automotive valve components recently and many of those valves were still serviceable, although on one I did swap the power supply vibrator for a solid state version at the owner's request. You can check my channel page for the playlists for those projects. Thanks for making a comment!

[@handsomemann1]

Great Fix. I enjoyed watching it. Looking forward to more transistor radio fixing. Or etc.

[@PracticallyFixed]

Thanks, it was a fun fix and it has an interesting element that was nice to hear how it worked. Thanks for watching and leaving a comment.

[@GeigerCounterVirtualMuseum]

Glad I ran across your channel. Subbed. Looking forward to watching your other videos. I never knew about that type of speaker. Very interesting.

[@PracticallyFixed]

Awesome, thank you!

[@PracticallyFixed]

If you get a chance, check out my latest where I use an inexpensive meter to detect radium on dials. Your equipment here would have been great. See Telechron Clock Project video.

[@spacemissing]

I have a P805A, apparently an identical cabinet molding (although mine is white) but definitely a different circuit board.
I haven't seen the speaker in it, but now I want to have a look in there.

[@teasea3152]

Your P805A has the same cabinet with a different grill than the P807 models. It definitely has a different circuit board with the big IF cans, an output transformer and a permanent magnet speaker. It also has the Conelrad markings on the tuning dial and used the large 9 volt battery. There's a repair video of your radio by All American Five Radio on CZcams if you're interested. Here's the link czcams.com/video/Ej7pJxMev8U/video.html

[@hestheMaster]

Great little vintage GE AM transistor radio with a little secret. Good thing the electrolytics were the only thing that were
bad in it and the PC board broke where the holder for the antenna was. I see GE made this type of reed speaker radio
even up to 1966 with the model P1730B. That was a six transistor pocket radio BTW.

[@PracticallyFixed]

Yes it looks like they made a flurry of them just briefly. Wonder what got into them. I think I read a German manufacturer used the design in the 40s, but otherwise it was gone by sometime in the 30s. Thanks

[@annaplojharova1400]

​@@PracticallyFixedEnergy wise electromagnetic (reed) speakers use to be more energy efficient than the dynamic (voice coil) types, what means they need way less audio power to make the same volume. That was the main reason they were used in the early days, when any significant amplifier power came at very large expense, being the tubes, but mainly the batteries to run them. I think that may have been the motivation here as well. Plus they were somewhat simpler so cheaper to make at some time (mainly along the need for lower audio power) and the stationary coil allows it to be made directly as high impedance device (lots of turn of thin wire is quite problematc to handle when it is supposed to be lightweight to move with the audio), so allows to get rid of output transformer.
But the mechanism is quite restrictive on the cone travel, which mainly affects lower frequencies (or requires bulky and expensive sound transformers), which make them disappear after all, in favor of the dynamic ones.
I think GE did not want to go the otherwise usual class B push-pull high efficiency amplifier for some reason (Patents? Availability of matched pairs? Feel like too many transistors? Eliminating audio transformers?), like to be as cheap as possible. Probably the extra current consumption did not bothered them, the battery cost to run it was not visible on the sale price sticker after all...

[@vintageradios7790]

Those speakers were very short lived. I have a GE transistor radio with this type of speaker.

[@PracticallyFixed]

It's ~60 years old and works well, unlike many other electronic things we could all name by a factor of 10. I can see its shortcomings in terms of frequency response etc. It is a rare thing to see these days, and perhaps even more rare to see still working. So we can hear how they sounded. Thanks for watching.

[@romjone4801]

I have a couple of other type of GE radios with broken Reed speakers. Do you have any suggestions?

[@PracticallyFixed]

Perhaps one of our viewers may comment here. I was lucky and mine seems fine. Depends on what is wrong. If the transformer has disintegrated I don't know what you could do. If the pin/stylus has come off then perhaps it can be reattached and glued back. Unfortunately since the radio circuit is designed to not have an output transformer, a "regular" 4 or 8 ohm speaker will not work, in fact may damage the output circuit. Wish I had better information for you. Good luck!

[@gdj6298]

@@PracticallyFixed Maybe a dummy load resistor, and a little IC amp which powers a conventional speaker ? They could even be mounted on the speaker so that if a proper unit becomes available, it could (almost) be dropped in.

[@user-vj7dp2ps9r]

I have fixed these to get playing ( only when the OEM reed speaker can't be saved) by gutting out the speaker cone and placing a slightly smaller modern PM speaker in front of that so the frame of the Reed speaker serves as mounting hardware for the new speaker. I did have to run the 3 wires from the board to an output transformer that I got from a junker radio ( impedance matching) then secondary to the new PM speaker. Mounted the transformer where the OEM coil used to be. Yes its no longer OEM but that was the only alternative as the OEM speaker could not be saved. Sound still tinny but not much worse than OEM.

[@johnchildress6717]

Looks better than o66s

[@PracticallyFixed]

Thanks. Did he do one of these? I must have missed it.