1955 General Electric 677 Transistor Radio

[batterymaker1]

I've had this set for nearly twenty years, but I haven't been able to enjoy it--all because of the battery.

This is GE's first transistor radio, loosely based on the Regency TR-1.

It uses an odd battery called a 239. It was a Minimax-styled
wafer stack tapped at 9 and 13.5 volts.

In previous years, I'd tried a few solutions involving zinc-air hearing aid batteries, but the results were full of fail.

Recently, someone asked me if I could make one for his--and he was willing to offer me an outrageous sum of money to do it...

Well, I told him he didn't need to "bribe" me, as I was thinking about having another go at making a viable 239. But I told him to give me a little time, as I had other orders to fill.

So, what to do?

First, I needed the cradle. This battery is not a simple box--it's octagonal.
So, I needed an octagonal holder.

I got that by making a dummy cover and lining it with transparent tape. I then poured in liquid Alumilite. The tape lining makes a great mold-release agent.

I now had a big black octagonal chunk of plastic. I cut a top and bottom filler section, drilled out a hole in the top section to accommodate a socket,
then added a notch to both sections. A circuit board with two N cell holders was then inserted in the middle.

Each holder was a "bank" for the respective 9 and 13.5 volts. In this case, a standard A23 garage door opener battery was inserted in the 13.5 bank.
A23's are 12 volts, so the loss of 1.5 volts was minimal.

To fill the other bank, I took apart another A23. Inside are eight 1.5 button cells. I took six of these and installed them in the other bank. Both banks are tied by a common negative.

Once the socket was wired in, I tried the set out. I had to fiddle with the set's plug for a little bit, and once I had it squared away, the set came to life.

I tweaked the IF's and the Oscillator, and got it to play decently. It's far from the best, not very sensitive and very thin, wispy sound, but it is one of the first transistor sets, so with that I say it's a success.

Now to make a few more 239's, work the bugs out of them, and add that battery to my ever expanding catalog. Work, work, work...

[paulsherwin]

Nice job as usual.

It looks as if the internal cells are actually AG13s. It might be better to build around these rather than using the door opener batteries, as you could add an extra cell to get the 13.5V (sub a couple of AG10s if space is tight) and they would probably be cheaper. You can buy AG13s in huge quantities for little money on eBay.

Paul

[batterymaker1]

I'll look into those other batteries.

BTW: Video is here--

http://www.youtube.com/watch?v=fwZFuM0w0-I

[newlite4]

Very nice job Bill, but it seems such a lot of effort to have to go to, you have great patience.
This problem of transistor battery obsolescence seems more commonplace in American transistor sets. This is probably because British transistor sets, which were traditionally larger and less needfull of miniaturisation, were released a few years after the US sets, by which time some battery and voltage standardisation had begun to take place.
Top job!
Neil

[batterymaker1]

Originally Posted by newlite4

Very nice job Bill, but it seems such a lot of effort to have to go to, you have great patience.

It would only be work if it wasn't fun! Having the goal of a playing radio with the battery you created--that looks like the original--is more than halfthe fun involved.

Lots of people say I'm a workaholic when it comes to these batteries. Workaholics, at least to me, are people driven by their work, no goal in sight, just work, work, work. For me, this is recreation, good exercise on the mind. And like Red Skelton used to interject on his show,
"...and the amazing thing about all this is that we get PAID for it!"

Originally Posted by newlite4

This problem of transistor battery obsolescence seems more commonplace in American transistor sets. This is probably because British transistor sets, which were traditionally larger and less needfull of miniaturisation, were released a few years after the US sets, by which time some battery and voltage standardisation had begun to take place.
Top job!
Neil

Somewhat, but not near as much. If you want to see a slew of obsolete transistor batteries, head to Australia. They had a full line of odd-sized 9v jobs that disappeared when Japanese sets flooded the market.

And, yes, I'm dabbling in working replicas of them....