Archive for April, 2019:

2019-04-20 DC to DC Converter for Tube B+

from FB group Building Transistor Radios Jon Edwards I’ve built a lot of JTs, they are useful for low power, under 100 mW. I got about 50% efficiency. What you have to do is make sure the reverse voltage emitter to base doesn’t exceed 5V, so it doesn’t waste power. A better way is to

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2019-04-18 We Take A Risk Every Time We Touch A Wire

from FB group Bell Telephone of… Apr 21 Jim Engle One time I was connecting up a POTS modem line and I was getting the crossconnect wire into the 66 block ready to punch them down. BRZZAP! I got zapped by the AC! Some idjit plugged a three prong plug into a 2 prong ungrounded

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2019-04-13 Olympus Digital Player Has Flutter

from FB group Vintage Electronics Test Equipment For… Apr 13 I see a Leader wow and flutter meter for sale. This reminded me of a problem I’m having with my Olympus digital recorder/player (WS-822, IIRC). I’m listening to it playing and it’s sounding like there is flutter in the music! That seems crazy to me,

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2019-04-12 Crazy Dangerous Invention

Bill Sherman I’m assuming you have to bend way over to use the machete. Weed whacker has a handle that takes care of that problem. When I was a kid, a neighbor was a real dangerous inventor. This was long before weed whackers. He took the impeller and shroud off a Hoover vacuum, leaving the

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2019-04-11 Northeastern Telephone Test Set TTS-4A

from FB group Bell Telephone of… Apr 11 I got the Northeast Electronics telephone test set TTS-4ANH and the first thing I did was open it up and remove the batteries. OMG! I took out 3 D cell and TEN of the cylindrical 9V batteries! At ten dollars per 9V battery, it will cost me

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2019-04-09 Event Horizon Telescope Hoopla Tomorrow

There has been a big media buildup to the scheduled release of the “picture” of a black hole. This was synthesized from data taken by multiple radiotelescopes around the world, and processed by supercomputers. More information. Update Apr 10 evening – As I had expected, the media made quite a big issue out of a

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2019-04-08 Output Transformers Construction

from FB group Regenerative Receiver… Apr 8 庄议翔 The power transformers have the laminations interleaved. The first lamination has an E then I, the next one has I then E. So the transformer core does not have any air gaps, because it does not have any DC flowing through the windings. The transformers for single

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2019-04-06 HP Transmission Test Set

from FB group Bell Telephone of… Apr 6 (I bought a transmission test set, TTS-4, photo at bottom.) Glenn Peters We had a HP 493something transmission test set for testing up to 56 kb/s lines. I remember seeing the symbols on the green screen, like a carriage return would look like a little ‘CR’. The

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2019-04-05

from FB group Vintage Transistor Radios April 6 I clicked on the link and I looked at the schematic. I’m surprised that in 1959 they had a radio that used the OTL amplifier to drive the spkr. I remember OTL was used in the early ’60s for Hi Fi amps, but I didn’t think that

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2019-04-02 History: Part Of City Of Orange Evacuated

From FB group Orange Talk April 3 That huge tank has got what looks like a refrigeration unit on its end. There are some chemical plants that use those for storing chemicals that are very dangerous. Decades ago we had a bad windstorm and the power went out in the industrial area where the railroad

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