Archive for the ‘Meters and Test Equipment’ Category:

2019-11-25 Fluke Meters, My Experiences

From conversation with Bill Sherman 2019 Nov 25 I had my new Fluke 75 for a year or so and one day I turned it to the off position but the display didn’t go off. I tried it a few times but the only way I could get it to go off was to remove

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2019-11-15 Build A LED Tester

Big Clive’s YouTube video Ohhh nooo! After all the trouble Big Clive went to show us how a Joule Thief works, he *digressed* to using a 9V battery for his LED tester! Horrors! 😱😱😱 I built a Joule Thief with a socket like he used for the LED. But the JT must not be left

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2019-10-21 Testing Transistor In Circuit

From FB group Vintage Transistor Radios James Ault Adam Bernhardt Maurice Wright is right. The tester puts DC through the device and measures its current gain. But when it’s in circuit it is amplifying AC such as audio or RF, and that’s not what a typical tester does. Any experienced tech will tell you that

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2019-09-30 RF Modulator

For the oscillator I used the Hartley oscillator circuit that is used in the Eico 330 signal generator. I didn’t need any of the range switches – I left that out. It used MPS6513 transistors which are cheap but very uncommon – I can’t remember ever seeing them in any schematics or in PC boards.

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2019-09-27 Phase Shift Oscillator For RF Signal Generator

2019-09-27 PSO I tack soldered the parts together for a PSO, and made modifications to get it go work at 500 Hz. My goal is to get a steady tone to use to amplitude modulate the RF signal generator that I have built (see this blog). The sine wave from this PSO is beautiful –

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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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2019-03-19 Radio Alignment Questions

From FB group Building Transistor Radios Mar 20 Bob Kirsch Any recommendation for doing a complete alignment? Documents? I used a HP sweep gen decades ago but I don’t have one now, just an old signal gen. I thought about building a sweep gen but I need to get a few parts. I have bought

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2019-03-11 Dipper, Wavemeter PT. 1

from FB group Building Transistor Radios Mar 11 I watched a YouTube video from Alan Yates VK2ZAY, he built a combination Dipper, wavemeter, receiver and RF generator. I built his schematic ‘right side up,’ he admitted he built it upside down with positive ground and drew the schematic, see: https://youtu.be/0pJw0m2Lz6o I didn’t attempt to build

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2019-02-20 Old 2N708 Transistors

Feb 20 I got 21 ‘packages’ of 2N708 transistors for $.99 a package from Goldmine-elec.com. In the box were 42 plastic zip bags, each having 5 2N708 transistors, so apparently one ‘package is two bags. Each transistor is marked with the Motorola logo and 2N708 and on the top KOREA is stamped into the metal.

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2018-12-12 LM78xx Linear Regulator Disadvantages

from FB group Building Transistor Radios 2018-12-13 Joseph Rotello I agree with some of your claims. But I know far more about 3-terminal regulators than you think. First off, your claim that they are more efficient is unproveable. There are linear PSes that are more efficient. That was the reason LDO regulators were used. You

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