Pioneer RT-909 Capstan Belt Replacement

The Pioneer belt needed for this unit is apparently no longer available. I do not know the correct dimensions. The old belt from the last installation I did had these approximate dimensions .31 in. (8 mm) wide by 16 in. (406 mm) circumference (certainly stretched) and .035 in. thick.

Replacement belts are sold by several vendors, none of which state the dimensions. One vendor, WJOE RADIO, claims his are 'custom made'. The dimensions of the belt we received from him are approx. .375 in. (9.5 mm) wide by 15 in. (381 mm) circumference and .05 in. (1.27mm) thick. The closest match to his belt from PRB is a slightly larger circumference (15.2) and more narrow (.265). I ordered another from eBay user tableterner. The belt they sent measured .275 in. ( 7 mm) wide by 14.75 in. ( 375 mm) circumference by .035 in. ( .89 mm) thick. This is most likely a PRB 14.6 but is not so identified and my measurements are slightly different from those stated for the PRB 14.6 belt (.27 by 14.6 by .033). I need feedback from those who have purchased belts from others regarding the dimensions of the item they received and the success of the installation.

The instructions I received from WJOE RADIO are barely adequate to do the job, which is true of all instructions I have received from belt vendors. Consequently, I created this set, about which I solicit comments/corrections.

Before you order a belt and replace it, check other deck operations
• Set power input settings to match your supply.
  This unit may be set for operation on power supplies of 120V, 220V or 240V at 50 or 60 Hz. To set it, remove the fuse holder and fuse, pull the plug out of the socket and reinsert so that the desired voltage appears through the notch in the plug. Check fuse and reinstall fuse and holder.
• Check Displays
  Plug the unit in to a suitable source and press the Power button. The counter and meter displays should light up. The counter should read 0000. The meter should show only a horizontal bar with legends. If neither display lights, check the power fuse. If it is good and neither display lights, or the displays are not as described here, you may have a serious problem that a belt will not correct.
• Check transport operations.
  Move both tensions arms to their extremes until you feel them lock into position (Rotate the left arm counter-clockwise and the right arm clockwise). This is a unique 'loading' position, from which no transport actions will work. Relax each until it is no longer locked in position.
  While holding both arms in that position, press the fast forwardbutton(>>). The right reel table should spin rapidly and the left less rapidly. Relax both arms until you hear a click and the reel tables stop moving. Move the arms back into the play position and press the Rewind button (<<). The left reel should rotate rapidly and the right less rapidly. Relax the arms again and wait for the reels to stop.
  Move the arms back into the play position and press the ForwardPlay button(>). Both pinch rollers should leap upward, pressing against their matching capstan shafts and both reel tables should spin rapidly. Press the Stop button and wait for the reels to stop. Move the arms back into the play position and press the Reverse Play button (<). Both pinch rollers should leap upward, pressing against their matching capstan shafts and both reel tables should spin rapidly. In each Play position, the appropriate direction arrow should light, indicating the play direction.
  In all 4 tests above, the counter should change values, up or down, depending on the direction of movement. Press the counter Reset button and the digits 0000 should appear.
  If any of the operations above are not as described, you may have a serious problem that a belt will not correct.
• Check audio output
  Plug in a set of headphones and install them (on your head!). The output from the headphones should be absolutely silent. If you hear static or a hum, try pressing the Monitor button in/out several times, then rotate the Input/output controls back and forth. If the problem persists, you may have a serious problem that a belt will not correct.
• Check for noisy switches.
  Push the Monitor switch (Tape/Source) in/out several times. Listen for noise and watch the signal display. If either your ears or the display indicate noise, you may want to attempt to clean the switch. Follow steps 2-3 below to remove the covers. Locate the Monitor switch and use compressed air, contact cleaner or WD-40 to clean it. If you're successful, leave the Monitor switch in the Source position and test the input and output controls (rotate them backwards and forwards several times). I find these units to be 'self-cleaning' i.e. some noise is normal when a deck has not been used for some time but it will often disappear after the controls have been exercised multiple cycles. If not, clean them as described above. 
• If the other factors look acceptable, order the belt. When it arrives, follow this procedure.

1. Tools needed: A long-shaft (6 in. ) #2 Phillips screwdriver. A non-magnetic tip is recommended.
   Really, that's all you need if you're skillful- and lucky. If you drop a screw while removing or installing it, you will need some needle-nose pliers or a magnetic-tip screwdriver (be careful to keep it away from magnetically sensitive parts). If wire harness clips make it difficult to move parts around, a pair of toe-nail clippers will prove useful. If you're over 40, a small flashlight will be beneficial!
2. Unplug power cord. Remove 4 screws on each side of the outer side/top panel. Pull outward on each side, lift and remove the panel.

   

3. Remove 4 screws that hold the back in place and remove the back panel. Note: the top 2 screws should remain in place. Pull out on the bottom of the panel and lift. You may find the top held with a strip of adhesive. If so, just carefully pull it loose.
   
   
4. Here is an overall view of the components inside:
   
   
5. From the top, you can see the capstan pulley, flywheels and belt in their normal positions
   
   
6. Locate a small vertical circuit board to the left of the capstan motor.
7. Remove 1 screw that holds the circuit board mounting bracket on the bottom. The bracket has slots that engage matching slots on the board and a vertical metal brace. Note their orientation, then rotate/wiggle the brace out of the deck and set it aside.
   Pull up gently on the circuit board to disengage it from a small 3-pin socket on the bottom.
8. Unplug the 17-pin connector plug on the side of the circuit board- note placement and orientation.
9. Gently move the board up and to the rear so it does not interfere with access to the mounting plate screws. You may need to clip small wire-ties and rearrange wires attached to the board to safely move it. Be careful not to stress the wires and connectors.
10. Remove 2 screws that hold another small circuit board on the capstan motor mounting plate just to the right of the capstan motor. Do NOT loosen the center screw! It holds a heat sink in place and has a nut on the back
    Move this small circuit board to the side and down to clear access to the plate mounting screws.
11. Remove the 4 screws that hold the capstan motor support plate in place. Grasp the end of the capstan motor, pull upward and back  to move the plate out of the way. You will now see the ends of the flywheels and the drooping old belt!
12. There are small plastic balls on the end of each flywheel shaft! They are only held in place with grease. Be careful not to drop them into the electronics and be sure to reinstall them upon reassembly.
13. Remove old belt. Clean the flywheels and the capstan motor pulley. Make sure they have NO oil/grease on the surfaces that contact the belt!
14. Place new belt in correct orientation as shown above.
15. Put a dollup of grease on the end of flywheel shafts, making sure the plastic balls are in place.
16. Grasp the end of the capstan motor and use it to guide the plate/pulley. Place pulley above its final position, slide down into contact with the belt, then carefully slide down into the position where the plate screw openings engage the mounting posts. While holding the plate firmly in position, replace the top right screw and tighten it to hold the plate in position. Making sure all 4 holes are properly aligned and the belt is properly positioned (it will self-correct minor mis-alignment later), reattach and tighten all 4 screws.
17. Rotate flywheels manually to orient belt and assure smooth operation. While doing so, check for end-play (there should be some-but not too much). If end-play is excessive, you may have lost the plastic balls on the end of the shafts!
18. Reattach the small circuit board to the capstan motor support plate with 2 mounting screws.
19. Return the other circuit board to its original position. Reattach electrical plug on the side (watch alignment of plug with mating pins) and press down to seat the connector on the bottom of the board. Place the mounting bracket back in position with both slots and the bottom screw opening. Secure with 1 mounting screw.
20. Plug power cord into wall, turn power on, hold both tension arms in play position and watch flywheels/belts for proper operation for at least 10 seconds. Do the same for reverse direction play.
21. Repeat steps above if problems appear.
22. Reinstall rear metal cover and replace 4 screws.
23. Reinstall side/top metal cover and replace 8 screws.

Document © by DanDLyin . Last Revised 15 November, 2007