Andrew of Andrew’s Telephony/IT Blog came up with a fascinating project where he built a 3-tap kegerator out of a 7 cu. ft. GE chest freezer, an Arduino, and a variety of flow rate sensors to display exactly how much beer is left in any keg at a given time. It’s a very in-depth project, and it looks like it’s turned out both awesome and functional.
Go check it out!
I’m looking at launching some easy to use kits of the most commonly needed parts, and maybe some helpful accessories and good instructions for the Bose 901 Series 1 and Series 2. No need to order the parts individually, just grab a kit and spend a few hours soldering and you’ll know you have exactly what you need.
Would anyone be interested in that? What other easy repair kits should I put together?
Let me know! Leave a comment or send me an e-mail.
I’m seeking a replacement power transformer for a 1931 Westinghouse WR-8 Columnaire grandfather clock-radio.
The radio uses the tube line-up 24 24 27 24 24 27 45 45 80; any similar 9-tube radio with a similar tube line-up is likely also sufficient. The Westinghouse radio uses the same chassis as the Radiola 80, shared by many models.
The main power transformer from any of these contemporary models will work:
RCA: Radiola 80, 81, 82, 86
Westinghouse: WR-5, WR-6, WR-7, wR-8
Graybar: 700, 770, 900
General Electric: H-31, H-51, H-71
Majestic: 90-B (*90 with no suffix is not compatible)
Period service replacements are:
Stancor P-713 (direct replacement)
Stancor P-6006 (universal replacement)
Line to 700V (350-0-350) @ 120 mA
5VAC center-tapped 3A
2.5VAC center-tapped 12.5A
2.5VAC center-tapped 3.5A
Please reach out via the e-mail address on my About Me page if you have one of these components for sale!
I’m still around – there are actually 3 projects on my bench currently that are ongoing, and I’ll hopefully have a few posts in the next couple of weeks were I fix a Philco Model 66, a Silvertone 1708A, and a Westinghouse WR-8 Columnaire. Until then, I’m quite busy, so things are moving a bit more slowly than they otherwise might.
I bought an inexpensive aftermarket car stereo about six months ago, and it’s sat unopened in my closet until this past weekend when I was able to find 30 minutes and actually put it together. The process in my 2003 Honda Odyssey was incredibly simple – six screws was all it took. And now I have a great, brand new Blueetooth and Pandora-enabled car head unit!
The feature I already enjoy the most, though, is the HD Radio receiver. I’ve never owned anything with HD Radio before, nor can any of my SDRs decode HD Radio as it is heavily protected by iBiquity patents. Let me tell you – it’s like night and day. FM Radio around the Seattle area is always spotty for some reason which I’ve always attributed to the geography. Even a big station like KNDD (locally, 107.7 The End) pushing 18.2 KW of transmitter power has static intrusion, fade, and general sub-par audio quality beyond the normal loudness war audio degradation.
Every time I tune a station on this new head unit, it’s like an immediate A/B comparison between Analog and Digital radio. The tuner first locks onto the analog channel, and there’s some hiss and crackle and the sort of noise you expect from radio. Then the “ST” indicator disappears from the dial and “D” appears when the digital sideband locks in, and the audio quality jumps, the sound field expands, and the artifacts melt away entirely. I swear, it’s like I’m listening to a CD. Except for the commercials.
It’s just amazing. It’s by far the best feature on my head unit, because it makes the experience of being lazy and passive in my music selections better like night and day. Now the music I listen to when I’m bored of my CDs, sounds as good as the music I’ve put some planning into bringing with me. If you don’t have an HD Radio already, you should definitely get one.
I recently got to fix up another Bose 901 Series 1 equalizer which I received for repair. These are some of my favorite electronics to work on – they’re easy to work on and each one has its own history. Every one of these I’ve seen has been slightly different and this one was no exception.
This one in particular has 4 separate repairs. One is especially interesting.
The last one is somewhat clever. A 10K resistor, probably 5W, across those terminals is the modification to run this equalizer on 240V in Europe or similar. It’s been jumped with a solid piece of copper bus wire taking it out of the circuit but still leaving it in the equalizer if conversion ever needs to happen again.
Top-off testing was next. The neon indicator lamp in the power switch was flickering badly – it had likely been losing neon through the metal-glass interface very slowly over the past 40 years. It’s a neon lamp attached directly across the AC mains with a voltage dropper/current limiting resistor in series. The total power consumption is a few mA at line voltage.
Here it is removed from the circuit. The lamp/resistor combination is actually a single component – they’re welded together. I replaced it with an NE-2A/150K resistor combination, I believe the resistor is 1/8W the draw is so small. The envelope size of the new bulb is about half that of the old one, but it fits in well from the bottom to let wire tension keep it in place better.
After burn-in testing, the equalizer checked out perfectly! It has incredibly clean switches. The others I’ve serviced are much improved after cycling but can hang up the first time they’re used and these didn’t even need cleaning.
This one is going to be a great performer for a long time, and these are a lot of fun to work on.
Marty KN0CK sent me some details to publish about his great looking miniature HF upconverter board for the RTLSDR, the HF Alchemy DVB-T Active HF Upconverter. It’s an incredibly miniature SMT board with an SA612 mixer and SMT oscillator, and with some very careful soldering the entire board fits inside the housing and draws its power from the tuner’s USB port. The design upconverts at 120MHz, which is well out of the FM band to reduce the possibility of interference from strong local stations. A 40 MHz low-pass filter on the input further reduces interference. Marty reports it works GREAT!
I also had the opportunity to test an identical dongle and it was very easy to use. It requires a PAL adapter, but most of these dongles need an adapter and this one wasn’t difficult to locate; the integrated form factor is excellent. It’s very sensitive, a bit more-so than my other tuner module even, and the integrated form factor is perfect. It would be very easy to purchase an active USB extension cable and locate this integrated SDR in a shielded enclosure at your antenna’s feed point for even lower losses and versatility.
Update 5/1/2013: KN0CK is releasing a Rev B! I have a teaser.
Thanks for sending this in, Marty!
I recently had a chance to repair another Bose 901 Series 1 equalizer. This makes quite a few of these that I’ve written up on here. One of my favorite things about seeing copies of the same model is getting to pick out the individual variations that happened in the production run and any repairs that have happened over the years, and this one is no different.
This one is new to my bench, it’s a 240V model! I haven’t had this one across my bench before – but the circuitry is identical except for the addition of a single extra resistor. Fortunately, I’m equipped for that!
This one looks like it’s in great shape except for a tiny corner that’s cracked but not yet separated.
It’s an incredibly simple switch. A 3W resistor dissipating about half that amount in series with the AC and the transformer, dropping the line voltage to 110V and feeding the standard circuit. It doesn’t look like this model has been repaired.
Capacitor replacements went according to plan, although one set of capacitors ended up being defective from the factory so I ordered a different set. Shown below are the good replacement filters.
All replaced! Precision 2% tolerance resistors, German-manufactured film capacitors, and modern replacement electrolytic capacitors. This equalizer powered right up and sounded great on every setting immediately with no further troubleshooting required.
Quite a few parts were replaced during this process.