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Sanyo Plus Q40 Strobe Light is Out

J

jamesc760

Active Member
I had a speed problem where it will slow down for a half second almost randomly, probably around once or twice in one minute or so. So I purchased a replacement motor with board (supposedly from a Q40) on a huge auction site we know well about. After replacing the bad motor with board, now the strobe light is out. All I did was cut the four wires from the old, took it out and put the new one in, carefully soldering the four wires.

Any suggestions? Anyone with a Sanyo Q40 have any ideas if the new motor with board can cause the strobe light to not work?

BTW, speed is now stable but the strobe lamp is out.
 
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Strange thing is there seems to be light under the platter, I've attached a picture that shows light reflected through the strobe lens under the platter. What's going on here?
 

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I put it back with my old motor board; strobe light works but there's the speed problem as before. At least this proves that the new (to me) motor board has a strobe problem. What to do?
 
The seller of the motor board offered to give back $15 for the trouble. I think I can fix the strobe lamp problem, probably needs the transistor(s) replaced.
 
what actually runs the strobe? Often its just a neon run directly off the mains frequency but some things run the light off the internal driver circuitry. If its just a boring old neon, those are typically just a bulb and a resistor. If the resistor is good, the neon itself is probably bad. They get flukey after a while and eventually just die.
 
I looked at the schematics in the service manual I downloaded. It seems the lamps are LED's, not Neon bulbs. They are driven by transistors. I'm not an electronics expert, just a hobbyist, so I may be wrong here. If electronics experts are reading this, please let me and others know .
 
I've found the cause of the random slow downs. VR33 was the cause. When I DeOxit'ed it, I had sprayed it from above, over the plastic cover, and it apparently didn't do anything. You must spay it from below, on the bottom side where the round screw hole is.

Another thing; even though the Q40 is Quartz Direct Drive, the VR33 will change the speed. I don't know the role of the Quartz, but on my Q40, it's acting like a non-Quartz, pitch controllable deck, the pitch is controlled by the VR33 (and VR45). Except, the pitch control VR's are very hard to get to.
 
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IIRC, the quartz is just an oscillator but, doesn't provide speed regulations. So, it would still need to be adjusted.
 
Yep, I think I'm going to replace the R331 with a potentiometer, extend it out and use it to control speed, and just leave VR33 alone. What value for R331?
 
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