Though not really a transistor collector, I thought the Sony TR-730 I found at a swap meet was cute and a fair deal @ $10. Inside the battery compartment was a label indicating that a Eveready 333 (4.5v) was used - a battery I'd never even heard of - and apparently not even made anymore. I found a few substitutes online for about $12 (or better) each - but I wanted to listen to my new radio NOW! Remembering a YouTube video I had seen, I popped open a 9v alkaline battery, took out the 6 AAAA-sized batteries inside, took 3 of them and soldered them in series with pigtails on the ends. Unlike standard batteries, the outer case is positive and the center rod is negative.


Here's the battery series, 2 pieces of 1/2" PVC pipe (1/8" thick and flatted on one side) and 2 terminals made from thin brass shim stock.


I stacked the batteries over each other - wrapping each one with a bit of electrical tape to insure insulation and to hold it all together - and soldered on the brass terminals. The PVC spacers are slipped over the terminals and the terminal lip is positioned against the flattened edge of the pipe.


A bit of hot glue was used to secure the spacers and terminals.


I then covered the entire assembly with 3/4" heat shrink tubing.


The battery assembly fits perfectly in the Sony, works well and allows the back cover to seat properly - and I made 2 batteries from a single, relatively-inexpensive, 9v. Being alkaline, it should outlast the original carbon/zinc 333. I'd imagine this has been done many times before - just thought I'd share my method of doing it.

JG,

Nice job, I've thought of trying that but was unsure of how flammable a battery is. I didn't want to take a chance blowing the damn house up.

Is it possible for that thing to ignite while soldering it?

E.J.

EJ,

I'm sure if you got them hot enough - those little cells would explode from the internal pressure - not that they would necessarily ignite! I made sure and cleaned both ends of each battery lightly with a wire wheel first, I tinned all hookup wire beforehand and I limited my attempt at soldering the battery itself to a couple of seconds at most. I made sure my Weller gun was up to temp before I tried. If the solder joint didn't take in a couple of seconds - I would have backed off and given everything a chance to cool before attempting again. Fortunately, I got them all on the first try. I used a protective face shield during the process. Please realize - this is how I did it for my own use - I'm not recommending that you or anyone else attempt this in any manner and to do so would be solely at your own risk.

JG,

Thanks for the clarification and the "DON'T TRY THIS AT HOME" disclaimer.

To bad you didn't post this in the HINTS and KINKS forum.

Its well written with clear close up pictures and would probably help alot of guys, besides the few of us transistor guys that view this forum.

Maybe someone will see fit to move it.

Again Great article,
E.J.

I have a 1960 RCA--- 3RH-34 that uses the same type of battery. I've been using Tadiran TL 5104 3.6V lithium batteries size AA that were given to me because they came out of some computers that were being recycled. Being down to the last of the batteries, I bought a 4.5V Dantona EN133A 600mAh at a local electronic store for $9.15. There are some equivalents online for less.

Dantona
http://www.batterystore.com/Eveready/A21PX.htm

Exell A133
http://www.batteriesinaflash.com/index. ... ts_id=1546

BTW, I've done a AAA battery pack similar to yours for a Emerson 838 Hybrid.

DA,

I saw those sites too - in fact, I ordered an obscure 15v battery for a multi-meter from the batterystore.com. $7 is relatively cheap - but I wanted to fool around with the radio and not wait on a battery (the 15v still hasn't arrived). I got 2 batteries out of that 9v for a couple of bucks - and as little use as it's likely to see, that'll probably last me for ages...

I'll probably do the same thing as it's a fun project. Several months ago I went to RS for a 4.5V battery, but they don't carry them in the store. Your message reminded me of the RCA, which I hadn't played in a long time because the last of the Tadiran batteries was so weak. I happened to drive by an electronic shop yesterday and dropped in to see if they had a 4.5V battery. It was pricey, but at least it was immediately available. I looked on eBay last night and found a seller who has ENERGIZER A133 Alkaline 4.5V Battery 2 Packs at $9.99 "buy it now", or "make an offer", but shipping charges are not stated.

Thank you for sharing this experience of yours. I also made up something like this in the past, i stacked 3 batteries for a desk lamp. I covered them with heat shrink tubing to keep them insulated and also prevent sparks or burn if the batteries messed up.

That is pretty steep.
If you're talking about the PX21 battery
there are some who sell it for about 7 bucks.
http://www.batteriesinaflash.com/photog ... ne-battery