Archive for the ‘Repair, alignment’ Category:

2018-12-03 My Fluke 75 DMM

from FB group Building Transistor Radios Joe Lima That’s good to hear. More than a year after I bought my Fluke 75 DMM (and with light use at home) I turned the switch to off but it stayed on(!!) I had to unplug the battery. Luckily it was still under the 3 year warranty, so

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2018-11-29 Fixing Badly Worn Volume Controls

from FB group Building Transistor Radios 2018-11-30 I’ve done some experimenting on volume controls that are badly worn and noisy. The idea is to substitute some resistance for the badly worn spot. The loud crackling will be reduced and the normal volume point will be moved to a higher point on the control. For a

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2018-10-26 TV Repair Was A Dying Business

From FB group Building Transistor Radios 2018-10-26 I repaired a lot of old tube TVs, and I saw that the repairs were dying when it was cheaper to remove the chassis from the old TV’s beautiful wood cabinet and buy a new cheap TV and put it into the wood cabinet. It even had a

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2018-10-07 Air Band Radio Kit HMOOABRA_4.3 Part 3

From FB group Building Transistor Radios comment 2018-10-07 Bob Johansen I don’t have a way of calibrating an RF signal level. Back when I worked on Aircraft radios we had General Radio VHF signal generators, attenuators and RF signal strength meters and a Panoramic spectrum analyzer. This would have been a piece of cake to

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2018-08-18 Two Types Of Germaniums In Old Radios

From FB group Vintage Transistor Radios There are really only two types of germanium transistors in older radios. One is for the RF and IF stages and has low collector to base capacitance. The other is audio and can handle a few hundred milliwatts. I recently replaced the germanium audio transistors with silicon, with change

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2018-01-01 H N Y! Old Germanium Transistors Lose Gain As They Age

Happy New Year! I replied to a comment by George Glavas on FB group Vintage Transistor Radios George Glavas I’ve never read any documents to back up your claim that “…germanium transistors lose gain as they age.”  I think that people believe this because old equipment has lost gain.  But all of the problems I’ve

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2017-12-30 Zenith Royal 755LK

I tried to to post this to the FB group Vintage Transistor Radios, but the FB app crashed and I lost several lines of my typing.  Makes me angry! The radio was not making any sound.  I removed the chassis from the case.  I found the ‘battery saver’ slide switch had been forced apart.  I

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2017-12-16 Olympic 860 Radio Capacitor Replacement 

I was the only bidder on a lot of three radios, one of them is an Olympic model 860 AM transistor radio.  This radio uses four AA cells for a total of 6 volts DC. Overall the radio is in good condition – no chips or cracks.  I powered it up and if I turned

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2017-12-15  Royal 500 Capacitors Replaced

From FB group Electronics Hobbyists, regarding the Zenith Royal 500 radios. Clyde Hendrickson  There are two 50 uF, 10V electrolytic capacitors under the battery holder.  Replace them with 47 uF, 10 or 16 volts. There is also a smaller capacitor next to the other, it might be a 3 uF, or a 16 uF, 10V.

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2017-12-03 AM Oscillator Instead Of Aux Input

From FB group Vintage Transistor Radios  For the last few months, ever since I started experimenting with oscillators on the AM broadcast band, my attitude towards auxiliary audio inputs has changed.  Earlier I thought  that it would be convenient to have an aux input.  But I was leery of making changes to the collectibles radio

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