Its not hard to make a signal tracer from an old AM radio. You need 60 mm of red and black flexible twisted pair, a 0.22 uF, 100V capacitor, a small black alligator clip, a 50 mm length of shrink tubing that will fit over the following probe, and a thin 100 mm long piece
(Read More…)
This morning on CBS Sunday Morning they had an article about a farmer who couldn’t repair his $800,000 John Deere tractor and lost several days of work. There is a growing movement in the US to make laws that require manufacturers to allow their customers to repair the equipment they own. This is a backlash
(Read More…)
From a comment I left in Big Clive’s youtube video https://youtu.be/jgaCYRc1-og In the past I’ve seen Clive having to replace “used up” capacitors in the ‘capacitive dropper’ circuits of low cost line operated devices. The problem seems to be common in other countries but here in the US I haven’t seen any problems with the
(Read More…)
I’ve been seeing the sprinklers reaching a smaller radius after several years, and brown spots between. I was thinking that it was caused by a clogged pipe. I also had some constantly leaky sprinklers that were causing the grass to become soggy and mushrooms were growing. Then I noticed my water bill was several tens
(Read More…)
Reply from FB comment Mark French I got a roll (on tape) of 22 uF, 10V and 47 uF, 10V tiny surface mount MLCCs. They’re not polarized, but I’ve heard they tend to be microphonic. I’m going to try leaving the old caps in and bridge a MLCC across them. They’re small enough to to
(Read More…)
2020 Feb 18 – Nobility 15 transistors OTL S/N (?J)29549 I replaced the electrolytic capacitors. The spkr buzzed when I touched the volume control. Nothing from the detector (transistor). It’s unusual. I pulled and tested some IF parts including one of the transistors, no problems found – transistor tested good. I called it a night.
(Read More…)
Zenith Royal 400 s/n Z551549 I soldered broken orange wire to battery holder. Replaced all four electrolytic capacitors. Silent speaker and nothing from earphone jack. I checked the voltage at the collector of the driver transistor, it was zero. One pin of the driver transformer primary measures 5.8 V, the other pin measured 0. Checked,
(Read More…)
From FB group This Zenith Royal 500H radio has the extra 8th transistor for the RF amplifier, so it should have excellent sensitivity and be able to pick up those weak stations. Most of the problems with old radios are with the electrolytic capacitors, but the Zeniths all use the carbon composition resistors and they
(Read More…)
Also to FB group Vintage Transistor Radios I finally drew the line and said I’m finished fiddling with this Zenith Royal 200 and put it back together. I got it without knobs or handle, and with all the transistors missing. It’s not pretty, and the speaker cone is warped and sounds bad. This is the
(Read More…)
Continued from post 2020-01-15 I dug through my drawers and boxes of transistors and found a bunch of MPSA56 PNP general purpose on tape, and put them into the LO and mixer. I think they helped slightly – they are lower minimum fT than the 2N3906s. I adjusted – optimized – the trimpots I had
(Read More…)
