The Silvertone Powermaster 634 Battery Tester
Monday, June 1, 2026 at 06:38:44
This is an interesting piece of radio history. Originally seen at the Findlay Hamfest in 2024, it showed up again in 2025, at which point I made the vendor an offer and took it home. Silvertone was the house imprint of Sears & Roebuck, once the “everything by mail” store in the USA. Sears expanded into physical stores, and devices like this unit would be sat on a counter at the radio department so you could test your batteries. Sears, of course, would be happy to sell you new “Powermaster” brand (another house imprint) batteries if yours were depleted.
The case itself is in ok condition, but it appears to have had some water ingress at some point. You can’t really see it in the image, but there’s some rust near the front of the slope. Note the two fuse clips near the top, those would have held the probes.
This is nothing more than a simple load tester, and is full of resistors to divide the voltage down for the meter and provide some load testing for the battery you’ve connected to it. It’s essentially a specialized voltmeter.
Before we go any further, does it work?
Sure does, this new battery reads decent on the unit. Probably will work a little better once probes are re-attached.
Of interest here is this knob. It appears to have been made in Chicago, and may have been sourced just for this device by Sears. After some research on this, the company, Davies Molding, appears to still be in business!
I have some cable and probes for the unit. Both of those were probably purchased at Mendelson’s Surplus many years ago, for far less than you’d get them today…I do miss that place.
It took a hot minute to figure out where the leads went, but after some investigation I determined that the negative goes to a big mass of resistors, and the positive goes to a terminal that has a second piece of phenolic on the switch. That one became obvious when I examined it with a magnifying glass and noticed it seemed to be a bit shinier than the rest, indicating it had been disturbed at some point in the recent past. Makes me wonder, did this thing have probes on it until recently and someone wanted those vintage pig pokers? Don’t know…
There’s still a bit left to do, I have some grommets on order for the holes and still need to solder the probes on, but this is what it will look like - eventually…
Stay tuned, this thing is going to work again soon!
References
Davies Molding, aka DAKA-WARE: https://blog.daviesm … om/what-is-daka-ware
Next part of this series: https://wereboar.com … hecker-finishing-up/