1937 Westinghouse WR 226 Vintage Radio Repair

July 27, 2014 Leave a comment

This 1937 Westinghouse radio was the second highest in their tabletop line-up for ’37 and featured 7 tubes and a large, eye-catching dial for easy tuning. After a full overhaul including capacitors, resistors, an eye tube socket rebuild, new power cord, dial cord re-string, line input addition, and a full alignment it sounds great and pulls in stations across the dial. This model had the alignment trimmers all on the underside which was annoying, but peaked up nicely nonetheless. Read more for photos of the rebuild!

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Check it out at Rain City Audio

Homemade North Korean Defector’s Radio [Photos]

July 25, 2014 Leave a comment

Radio might be taken for granted here in the U.S., but in other parts of the world it’s still a vital link in receiving underground information in repressive regimes. This story out of North Korea from NK News shows just how important it is in some other parts of the world.

Doesn’t look like much, and apparently it was pretty tough to operate without a tuning dial and with such a small tuning knob on the front:

The radio therefore leaves users to depend totally on delicate hand skills to turn the manual module in micro-inches every time. NK News staff could, however, easily experience the frequency changing with slightest turn of the module either to the left or right.

That knob would be controlling the variable capacitor on the board, shown bottom left:

This is interesting. It’s clearly an adapted PCB from another device, which looks to have been modified with a few additional capacitors and other components on the front end and possibly the amplifier area. It’s tough to tell how much is in use for this modification, though. This might have been from a tunable radio smuggled in elsewhere and modified, or could have been a state authorized radio modified to tune a different frequency range.

It looks like two new coils are in place, which could correspond to an antenna and oscillator coil. These would definitely need to be replaced to change the tuning range of the radio. They could be coils to adjust an RF tuning range for two stages of an RF amplifier, though. It’s tough to tell from the circuit board the principle of operation of this radio – it could be a superheterodyne receiver, which would offer a bit better performance and would be able to tune the FM signals as well as AM/Shortwave, but it could also be a tuned radio frequency detector which would be able to pick up the AM and Shortwave bands only in most circumstances.

The superhet would leak a low-level oscillator signal that could potentially be picked up by counter-intelligence agents to determine if someone was listening to a prohibited broadcast (although the average law enforcement officer in North Korea might not be sophisticated enough to operate direction finding equipment to find such a receiver) but would be able to pick up FM transmissions as well. The TRF type radio wouldn’t leak a local oscillator signal but might not be able to effectively decode an FM transmission depending on its construction. Really, it’s likely there are a variety of underground radios with different capabilities depending on what can be scrapped together at the time.

This all goes to show that hacking circuits is more than just a hobby – it can have real, life-changing implications for people in other situations using the same skills. That’s pretty powerful.

For more about this particular radio, visit the Original Article at NK News.

For more about underground information access in North Korea in general, The Atlantic has a great piece in their April 2011 issue.

1969 GE Model C2504B Transistor Clock-Radio Repair

July 22, 2014 Leave a comment

This iconic late ’60s GE clock radio came to the shop with loud, low humming when turned on and no radio reception. That’s a familiar problem! Time for new capacitors. This particular used a 100 uF main filter and several 200-400 uF secondary filter capacitors around the boards, along with three electrolytic coupling capacitors in the signal chain. They were very tired and as shown by the hum had started to short out; if the radio continued to be run with the loud hum it could have been badly damaged so it came in just in time. Some new components later, she’s good as new and sounds surprisingly good for such a small radio. There’s a mystery switch inside, too – do you know what it might control? Read more for more photos of the repair.

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Check it out at Rain City Audio

1935 Silvertone 1827 Antique Radio Repair

July 17, 2014 Leave a comment

This Silvertone 1827 with an artistic finish came to the shop for an overhaul. It had been kept running for about two decades by its original owner before being put aside, and ended up getting all new capacitors and a new #85 tube which had shorted out. It had been well loved as the quality of the historical repairs was very high, and it had all Silvertone brand tubes, so could even have been dealer-maintained at Sears its whole life. After component replacement and an alignment, it really sings and has spot-on dial tracking and even pulled in a shortwave station. Read more for details and more repair photos of this Silvertone 1827 vintage radio.

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Check it out at Rain City Audio

Bose 901 Series II Active Equalizer #103549

July 10, 2014 Leave a comment

This Bose® 901 Series II Active Equalizer is a part of Rain City Audio’s parts stock and got a full rebuild with upgraded parts and complete and comprehensive testing. All transistors, resistors, film and electrolytic capacitors were replaced, a new neon bulb added, and the controls cleaned and lubricated. This very detailed repair walkthrough has photos showing the drifted carbon composition resistors which can throw off the equalizer’s curve even if all the capacitors have been replaced. Click through for many more photos!

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1959 Magnavox AM-80 Companion Transistor Radio

July 5, 2014 Leave a comment

This little 1959 companion transistor radio came through the shop for a tune-up. It, like most of the others, was in good shape except for the capacitors being dried out and no longer performing their functions. One was badly cracked, even, but the radio still worked after a fashion. With new parts installed it’s good as new. Keep reading for detailed photos of the tear-down and replacement parts.

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Check it out at Rain City Audio

Now for Sale: Westinghouse H-126 Little Jewel “Refrigerator” Capacitor Replacement Kits

July 2, 2014 Leave a comment

Rain City Audio is proud to announce a new product offering: capacitor repair kits for the Westinghouse H-126 Little Jewel / “Refrigerator” Antique Radio!

This repair kit contains the most commonly needed parts to refurbish your Westinghouse H-126 Little Jewel / Refrigerator radio. You’ll receive 13 modern, high quality replacement film and electrolytic capacitors to bring your radio up to full performance. Take the guesswork out of fixing your own collectible model of Little Jewel, and save the hassle of using a parts site like Digi-Key,  and order a kitted set of parts that’s ready to replace.

Included in this kit:

1 x 0.001 uF (You’ll receive 0.001 uF)
1 x 0.2 uF (You’ll receive 0.22 uF)
2 x 0.04 uF (You’ll receive 0.047 uF)
1 x 0.005 uF (You’ll receive 0.0047 uF)
1 x 0.025 uF (You’ll receive 0.022 uF)
2 x 0.01 uF (You’ll receive 0.01 uF)
1 x 0.1 uF (You’ll receive 0.1 uF)
1 x 0.1 uF (You’ll receive an X1Y2 Safety Capacitor to replace the across-the-line RFI suppression capacitor.)
1 x 20 uF 50V Electrolytic (You’ll receive 22 uF 50V)
2 x 50 uF 450V Electrolytic (You’ll receive 47 uF 450V)

Westinghouse H-126 Little Jewel/Fridge Capacitor Kit – $39.00 with Free Shipping!

 

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