Pilbeam Engineering

Well, I have finally got around to finishing my 1929 Philco 76 AM radio. This radio is an AC set by Philco, it uses TRF circuitry and tunes the AM band.

When I first got the radio, it more or less worked, but suffered from problems with the power supply, as many radios of this vintage (or newer) do. Specifically, it fell to me to replace the power supply filter capacitors, which I did shortly after I got the set (some years ago, now). After finishing that, I found that the field coil on the electro-dynamic speaker was open and therefore unusable. I cobbled together a way to replace the function of the field coil for the radio’s circuits, but I kept my eyes open for a correct speaker replacement. I found a new speaker (new to me, anyways), and installed it. Having finished that, I found the radio would play well for several minutes, but gradually the audio would fall away in volume.

So, I took it upon myself to begin re-capping the entire set at that point. With all new audio-stage capacitors, and the RF coupling caps replaced, I felt I’d have some success. When I got it all back together after the recapping, and plugged it in, I found that I had very low volume even though the volume control was maxed. In fact, in spite of the low volume, the audio that was being provided was distorted, as though the amplifier was working its hardest to give me even that small amount of sound.

Thus my suspicion fell to the interstage audio transformer…which had already been replaced at some point in the long distant past. Since the available schematics do not provide information on the impedance of the original transformer, and the unit I had was bad, it was difficult to find a suitable replacement. Some research online, however, helped me. Another person with, I think, a Philco 87 had used a Hammond 124a transformer on his set. Having looked up the specs for that particular transformer, I was delighted to find that one of my spare replacement transformers for the Atwater would probably do the trick -- at least they had very similar DC resistances. So, I quickly installed it to test it -- and it worked! This is probably a testimony to the lack of electrical diversity in 1929 radios, haha!

I was pleased, and quickly started buttoning everything up. For the first time in years, the radio chassis is actually bolted into the cabinet (never saw the point while it was mid restoration). Reception is good, audio quality is suitable (it sounds better than the Atwater, which has an odd flutter I can never seem to trace), so I have no complaints. The only other task I may undertake is to replace the power cord -- it’s in generally good shape, but brittle. For now I have the set connected to a power strip that I shut off when not in use…but will be ordering some cloth-covered cord stock when I get a chance.

Enjoy this video of the Philco in operation!

So, a week ago I purchased a typewriter. Not the sort of thing you’d expect a young computer/network engineer to do, to be sure.

However, in keeping with my desire to slow down and become more focused in life, I thought it might be fun to try to write without getting easily distracted, as I do on the computer. To that end I started researching typewriters. I find that hand-writing everything tends to tire my hands out quickly, and my quality/readability rapidly degrades. By using a typewriter I can focus on one thing: writing. At the same time I retain the efficiency and speed of typed text – for the most part.

I spent several days researching typewriter makes and models. Since I tend toward older equipment (just look at some of my radio posts!) I opted for a manual model. Something simple, yet elegant. I finally decided on an Underwood as they were reported to be fairly fast machines. I was able to find one on eBay for $95 plus shipping, with came to about $25. All in all not bad for a unit from 1936 that weighs between 30 and 40 lbs. Once I got the machine home (which took a week with UPS), I was able to start cleaning it up. Aside from a bent platen shaft (which I was able to fix pretty well, but I couldn’t remove the platen to fix it perfectly – you can’t tell it was bent now though) the machine arrived in nice shape.

I’ve purchased three ribbons, and it had the original metal spooled ribbons in it (or at least similar vintage ones) so I should be set for awhile. I can, of course, re-ink the ribbons or just buy ribbon material sans spools. I’m pleased at the parts availability though, this is the power of the Internet – one can easily find even obscure parts. I will admit to having had to read the manual (for an Underwood #5) to figure out the ribbon mechanism, it kept bunching up vertically as I’d type, which wouldn’t do at all.

The Underwood typewriters support single, double, and triple spacing (easily adjusted through a small lever) as well as tabulation (need to learn how to use it!) and dual color (black/red) ribbons. I suppose if I were to do accounting the dual-color might be useful. When I was cleaning it, I’m pretty sure someone used green in it for a long period of time as the ribbon rollers were caked with green ink. The Underwood makes for nice typing once you get a rhythm going, and since it’s in splendid shape I should get quite a bit of use out of it for a long time to come.

Now I’m contemplating getting an IBM Selectric for the office…but I think I’ll wait to see how I make out with this manual model first.

That’s all for now

-Adam

Edit: May 8, 2010

I’ve added a picture of the typewriter ribbon path for any inquiring minds that may have issues with ribbon binding, tearing, etc.

Please note that the spring loaded paper guides are in their down position to allow you to better see the ribbon.

You can click the picture for the full size view!