Introdução
This very basic record deck with electronic speed control had been stored for several years and would not start when powered up. The jammed motor was simply freed-up by removing the platter (turntable)and belt and gently turning the motor spindle by hand. The speed selector switch was then found to be unresponsive and needed cleaning. The fine adjustment potentiometers were also cleaned and adjusted to give the desired 33rpm and 45 rpm platter rotational speeds. Then the record player worked fine. No costs incurred.
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First image shows general view. Note there is no rubber mat to pull away from the platter (green arrow) as it is a single assembly. Pink arrow shows speed 33/45rpm switch (see later steps).
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Second image shows how to lever out the circlip (red arrow) with a flat end screwdriver (care not to lose the circlip if it pings off!). The platter can now be simply lifted off.
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With the platter removed, the belt (red arrow) falls away and the motor spindle (blue arrow) is exposed. Turn the motor spindle gently by hand to un-jam it. I put a drop of light oil down the spindle shaft to lubricate the bearings (some motors have an oil hole marked 'oil'.) Clean any dirt/fluff/lint from around the spindle.
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There is a helpful plastic protruding hook (red arrow) on the underside of the platter to aid reassembly of the belt as there are no holes in this platter to put your finger through, to hook the belt back over the motor spindle.
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Fit the belt around the inner flange and pull the belt out to position it over the round part of the hook as shown. It should stay in position, if not the belt has stretched and needs replacing.
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Now reassemble the platter in a position so the motor spindle is somewhere between flange and the hook. Now manually turn the platter clockwise (about a quarter turn) so the spindle pulls the belt off the hook and onto itself. Check the platter rotates when turned on. If not repeat above step.
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If you don't have a hook on the underside of your platter, it can be tricky to get the belt back on. You may need a bent piece of wire or to have very thin fingers!
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If the platter turns OK with the motor on, re-attach the circlip into its groove with the help of the flat part of the screw driver rather than your finger nail. Job done, though in my case there was another problem, see next step.
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Having unjammed the platter, I noticed the speed controller rotary switch (which selects either 33rpm for LP's or 45rpm for singles) was unresponsive and only gave about 22rpm (determined by counting the number of revolutions each minute on my watch).
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To measure the rotation speed, you can use a smart phone app if you prefer (see image). Note: the two sets of lines on my platter rim are not strobe lines for speed measurement, but just decoration!!
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I removed the four foot screws to remove the hardboard base cover to expose the BSR94HB electronic speed controller circuit board next to the motor as shown. I observed black dirt (red arrow) around the contacts of the rotary switch which I cleaned off with switch cleaning lubricant (Kontackt10 super) with cotton bud and paper between the contacts.
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Playing a record, I couldn't tell the speeds were slightly too low (30/44rpm), but anyway I I did clean (with above lubricant) and adjusted (by trial and error) the fine tuning potentiometers (one shown as orange arrow) . Clean again if necessary to get consistent results.
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