: Magnavox 1SC261 mini trapezoid ...  ( 121 )

Motorola Minion

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Magnavox 1SC261 mini trapezoid ...
« : April 26, 2021, 09:16:05 AM »
Since I have no pics I can upload OR downloads to refer back to, here is what I worked on.
https://www.ebth.com/items/4690509-vintage-magnavox-record-player

The repairs were very easy in part because it seemed to have been used lightly then never serviced. The best scenario but it still required a fair amount of parts and while a used model can be had for 4 Jacksons like in the link, the final bill to my customer will exceed that.

The tiny 3-tube chassis uses a 7025 preamp tube, one triode for each channel. Two output tubes are 50EH5, a higher gain version of the 50C5. These drive a pair of 8" round speakers, with no tweeters that I could find. The Sams photofact was found after using the 80-02-00 number stamped on the amp chassis. Several resistors drifted high but the 3-section electrolytic was an OEM Mallory (EIA 240) that reformed 100%. Not a typical case at all.

One of the original 50EH5 tubes was gassy, partly revealed by tube tester but confirmed with my Fluke meter on the grids of both tubes.

The Collaro changer had a frozen motor and cycle wheel, finally the 78 rpm needle was gone from the EV-26 cartridge - otherwise was in very good condition, just dusty with orange hardened lube everywhere. I fitted it with new Pfanstiehl 352 diamond 33/45 and a new 78 rpm sapphire.

The hardened idler pulley made awful noise, so a nice soft one was pulled from another player to replace it. These Collaros are different animals than a V-M but more easy to service once you do only what you need. I may retract that last statement as I have 4 more Collaros and 4 more Mag changers to work on!




 
Tubes - Magical - Tubes

Dave

firedome

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Magnavox 1SC261 mini trapezoid ...
« #1 : April 26, 2021, 09:48:01 AM »
Sounds like a winner!
Would one have to worry about that Mallory even though it reformed for now?
Happy Motoring! from Roger in NY

Bill

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Magnavox 1SC261 mini trapezoid ...
« #2 : April 26, 2021, 12:59:12 PM »
Nice job Dave, and an interesting shape for a table top unit.  Like Roger said, will the can electrolytic be OK reformed?

Bill

firedome

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Magnavox 1SC261 mini trapezoid ...
« #3 : April 26, 2021, 02:46:47 PM »
Like the old repairmen say, an old electrolytic is either bad, or is about to be!
Happy Motoring! from Roger in NY

Motorola Minion

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Magnavox 1SC261 mini trapezoid ...
« #4 : April 26, 2021, 04:33:52 PM »
This is one of those repairs that will last due to the relatively low voltage involved. The cap is rated at 200V and the highest voltage is 125. If not, a 22 ohm wirewound fuse-resistor would open.

Series-wired stuff is self-protecting with resistances that open without too much smoke. I have a Westinghouse console that has no fuses and that bothered me until I thought about it. That one did need caps and a selenium rectifier swapped with a 1N4007 diode and dropping resistor.

Never even consider running a transformer on line voltage without a fuse or breaker in the primary.
Tubes - Magical - Tubes

Dave