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Vintage Sharp RT3388 tape deck runs with switch off and VU meters not working

Florida21

Jul 11, 2022
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Running out of ideas and looking for help from you experts. Switch appears to be working since the counter goes to clock whim turn unit off but tape still plays. No response from meters or movement
 

Harald Kapp

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Nov 17, 2011
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More details please. E.g. which switch (there's more than one).
 

Florida21

Jul 11, 2022
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More details please. E.g. which switch (there's more than one).
So sorry….the main switch to turn unit on/off. When the power switch is in down/Off position all lights turn off, which I had fixed, but the tape deck still runs. Also no response from meters when tape is playing
 

Harald Kapp

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Obviously the main switch doesn't control mains. There seems to be an auxiliary power supply that is constantly powered. The main switch then only uses this auxiliary power to turm the rest of the unit on or off.
Best way to analyze the defect would eb to have a schematic at hand and trace the voltages in the power supply section. Clearly something is wrong there.
 

Florida21

Jul 11, 2022
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Thanks Harold. Fortunately I have the schematic but unfortunately I’m too much a novice and was hoping someone had run into this before That could lead me. I know, I’m the worst type. Lol. But I’m trying here
 

Florida21

Jul 11, 2022
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I’m adding some pics of the unit and screen shots of the schematic. Hope this helps in your expertise in helping me. Hope the pics came out clearly
 

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kellys_eye

Jun 25, 2010
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If this function worked prior to your previous repairs then check your work around Q808 as this is very close to the switching arrangement that controls the power to the motor. You might have shorted a track or even put the transistor in the wrong way around.
 

Florida21

Jul 11, 2022
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If this function worked prior to your previous repairs then check your work around Q808 as this is very close to the switching arrangement that controls the power to the motor. You might have shorted a track or even put the transistor in the wrong way around.
This function was not working when I purchased the unit and I even tested that part but I will be working on it this weekend and will just replace part. Will report back results. Thank you
 

Florida21

Jul 11, 2022
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I actually have 2 sharp units. Same as above. My working one that I fixed with help on here just realized the solenoid/plunger not working. I did check for ohms and seems fine. Without test equipment, I also tested with 9 volt battery and it did move. I attached additional info from schematics as well. Also, I pulled Q802 & Q803 and are good.
 

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