Motorola Model SK40M-1

Electrically amplified phonographs or radio/phonographs and related components (approx. 1928-1990).



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knhooper
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Location: alabama

Motorola Model SK40M-1

by knhooper » Mon May 28, 2007 5:43 am

Hello all,
Just found this site and am needing some help with a record player I inherited from my parents. It was built in the late 50's or early 60's. It still comes on and the turntable turns but when you put a record on it you can barely hear any sound coming from it. I know it is not worth much but I would like to have it working for sentimental reasons. My parents bought it when I was very young and I can remember playing records on it. I still have all their LP's and would like to enjoy them in my old age. Could it be the needle or the cartridge the needle sits in or what???? Any help would be greatly appreciated.


Bobby Basham
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Location: Tucson, Arizona, USA

Re: Motorola Model SK40M-1

by Bobby Basham » Mon May 28, 2007 6:44 pm

knhooper wrote:Hello all,
Just found this site and am needing some help with a record player I inherited from my parents. It was built in the late 50's or early 60's. It still comes on and the turntable turns but when you put a record on it you can barely hear any sound coming from it. I know it is not worth much but I would like to have it working for sentimental reasons. My parents bought it when I was very young and I can remember playing records on it. I still have all their LP's and would like to enjoy them in my old age. Could it be the needle or the cartridge the needle sits in or what???? Any help would be greatly appreciated.


Howdie....
Is this a tube model or solid-state? Speaking for myself, I like to start with the process of elimination. If the radio/tape/aux connections work, then narrow it down to the turntable. It could be a number of things. I check all connections from the cartridge to the preamp section. I've even swapped cartridges from a similar unit. If everything (radio/aux/phono) acts up, then you're problem is elsewhere in the amp. Replacing the caps can solve a lot of problems and/or new tubes if your unit is that old.

Im sure others will chime in here, hopefully Record-changer. After going through so many units myself, it seems that the problems can be narrowed down fairly easily. Usually capacitors, cartridge, and an occasional driver transistor, usually something typical for units this old.

I hope you can get it up and running for these are truly marvelous beasts and I enjoy their warm sound. I've got several thousand albums and have a console in every room and about 11 stacked up in the spare bedroom for when I get a bigger place...LOL. There are good folks here on the board and I'm sure you'll have your problem solved. Best to You.

BobbyB
Tucson, Arizona


Thom
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by Thom » Mon May 28, 2007 8:35 pm

If you can upload a picture or few that would help. Also the manfacturer and model number would be useful. Dittos to BobbyB, except I don't have consoles stacked in my spare bedrooms... yet. Surely BobbyB is not married or he has a most understanding wife. :lol: Good luck.
Vinyl is disease which attacks that area of the brain desiring digital recordings. Once you catch it, you are cured.

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Record-changer
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by Record-changer » Tue May 29, 2007 8:56 am

There are several possibilities:

- Crystal and ceramic cartridges degrade over time with exposure to humidity.

- Check the muting switch. The original parts on Collaro record changers made in the 1950s and early 1960s are made of mica. It crumbles over time, leaving the switch permanently in the mute position (I used plastic guitar picks to repair mine). Other changers could have similar troubles.

- Bad tube or transistor (usually affects only one stereo channel, unless it's a dual section tube for both channels).

- Lost diamond stylus tip (the cantilever is playing the record instead of the stylus).

- Damaged pickup wiring.

- This is farfetched, but one unit I looked had no woofer speakers. It turned out that the teenaged son of the owner had removed them.
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shedradios
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by shedradios » Thu May 31, 2007 4:54 am

According to SAMS data the set dates to 1961. The Motorola stereos amplifiers from this time are very good. All input by others here is good advice. The amp needs a rework no matter what other problems need fixing.

"It still comes on and the turntable turns but when you put a record on it you can barely hear any sound coming from it."

What do you mean by comes on? Do the tubes light? Any other sounds? This amp has a fuse and it's under the chassis. Ain't that sweet. Since this has a radio input if you could just plug in an output from a CD player or some other source you could test the amp. Worth? The amp alone would probably get you more than the whole thing. These are good amps. Good tubes all expensive. But fix it up and enjoy.

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