Question about Audio Shelf Systems
Hello I have a SHARP VZ-2500 system that needs work doing to it; such as new turntable belt, cassette heads replacing, bulbs etc... Is there anyone who's a specialist with these on this site who could help the audio repairers once they begin work on it? Many Thanks.
SOURCE: Cassette Player
Motor speed needs to be regulated by PWM. Reducing the current (with a resistor) actually lowers the torque - which, with a given load, does result in reduced speed - however, different length tapes (60min vs 90min), as well as different quality, and even current position in the tape, will change the load and hence the speed. You need to regulate the speed via PWM. It's sometimes done on a small board built into the motor, in which case you'd have a round hole into which you could insert an INSULATED screwdriver (tiny flathead wrapped most of the way in electrical tape works). It may be done on the main board, in which case you could find a pot conveniently labeled "motor speed", or perhaps "pulse width" or "pwm" or something to that effect. Find it, mark its current position just in case, and turn it to see if it gets the effect you're after. And there are some tape decks in the world with no speed adjust - they are designed with a specific speed motor and the sizes of the wheels and gears are calculated for that speed. Also there may be a mechanical fault/malfunction causing the speed problem. An initial check and thorough cleaning of the capstan and pinch roller should be done. If there is a buildup of tape oxide or a piece of a broken tape wrapped around the capstan, the tape travel will be too fast (do to the effective increase in capstan shaft diameter). If the pinch roller isn't fully engaging, the tape can be getting pulled onto the takeup spool at a speed faster than the capstan control. A different source of trouble might be a slip clutch (possibly an idler/clutch assembly)which is binding, or otherwise not functioning the way it should. Another type of motor doesn't have it's speed controlled by an internal or external voltage.. instead, the motor has an internal centrifugal speed controller. This type of motor can be found on older tape decks, and might not have been utilized more recently. Good luck
Posted on Mar 14, 2006
Most of these are blet driven and the belt is probably slipping. This is a relatively simple repair if you have the correct belt. I'm in Massachusetts, so I don't have any particular recommendations for you. The belt will cost around $10.
Posted on Mar 21, 2008
I had the same problem & came up with this solution. It is very simple.
Take the platter completly off the turntable by pulling on the nipple in the middle of the platter. If you are unsure what the platter is it is the base that the record lies on. It may take a good pull to get the platter off.
Take the belt completly out of the turntable. On the underside of the platter you will see a large circular lip. Wrap the belt around the exterior of the lip. Make sure that the belt is flat & not twisted.
Inside the turntable you will see a large round white gear. On the edge of this gear you will see a semi circle cut out of it with no teeth on it. Align this groove facing front & center of the unit. You can feel it pop into this natural position.
Take the platter & on the underside you will see a small white gear in the center. On the bottom edge of the gear you will see a square notch. This square notch needs to face the front & in center of the unit.
On the inside of the turntable there is a small white wheel on the right side near the record player arm. This is where the belt has to wrap around. This is the motor.
Take the platter & sit it on your lap with the underside facing up. Align the square notch that's on the gear so it is facing 12 o'clock. Pinch the belt at 3 o'clock and pull it a couple inches away from the lip.
Now flip the platter over & be prepared to install it in the unit.
With the belt pinched away from the unit slip the pinched portion over the the small white wheel that is the motor. Put the spindle that is in the center of the platter into the center hole of the turntable. Make sure the belt does not get twisted & that the belt is still on the outside of the lip not getting pinched or hanging off. Remember to keep the square notch that is on the the underside of the platter facing front & center. This step may take a few tries so just be patient.
Now push the center of the platter all the way down as far as it will go.
Turn on the turntable & enjoy your vinyl!
Posted on Jan 31, 2009
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