This post is one of 3 related posts. I'll remove this line when they are complete.) (The videos linked to in this post are not by me.) Most of these units have a broken belt. The factory service manual has belt replacement instructions besides other procedures. You should have this manual if you are going beyond belt replacement. This link is for straightforward belt replacement and includes excellent photos, but involves about a dozen solder points: https://stereo2go.com/forums/threads/aiwa-hs-j09-restoration.5462/ This video has an extensive preparation for the work and goes farther than belt replacement: AIWA HS G600 Auto Reverse Issues - Troubleshooting: Since soldering is necessary to change the belt but many people are not comfortable soldering, I worked out a way to minimize the soldering. The downside of this method is that some components dangle from wiring. Which makes things awkward and collateral damage more likely. I have used the official part names from the factory service manual. If you are going to be taking these units apart many times, it may be best to bite the bullet and desolder the ribbon cables. Document every thing you do. This could include making a numbered list of every action. Take photos of each action before and after you do it. Include photos of the solder points for the AM antenna as they may break off while you work. Take lots of photos of parts you don't expect to work on. There are all sorts of different tiny screws. They are extremely easy to lose and very difficult to buy. Arrange a work area that will contain them when you drop them. Which you will. Do not work over or near carpet. It is easy to mix up which screw goes where. Take macro photos of them after removal but sitting beside where they came from. Fold them into pieces of tape numbered with the step in the process. Disassembly Procedure 1. Unscrew the black jack panel. There are two plastic hooks under the radio dial side, so raise the other side first to disengage them. The two black sliding switch knobs will disengage. Carefully store the knobs. There are two white plastic gears under this panel. One is not secured and can fall off and disappear. Finding or making a replacement verges on being impossible. The other gear is secured by a screw and metal plate. Remove them. This gear includes a shaft that engages a tuner gear deeper in the unit. This gear will rotate and pull out. * Reassembly step (G) 2. Remove two even smaller screws on the cassette lid trim panel. The panel hooks into the cassette door on the far side from the screws. Raise the "Aiwa" label end first. Unstick anything holding the equalizer slider assembly from the trim panel. Leave the equalizer assembly dangling from its ribbon cable, but be careful not to tear it or stress or bend its connections at either end. 3. Remove 2 screws on the chrome control panel. Note these screws look just like the ones on the rear cabinet panel, but these have shoulders while the rear panel screws lack the shoulders. Don't mix them up. The green slider knob is securely attached and never missing. The 3 white slider knobs will come loose with older production units. The newer production knobs have tiny tabs that make them less likely to disengage from the panel. Secure or store these knobs. * Reassembly step (F) 4. Remove the 4 screws securing the rear cabinet panel. Take a photo of the exposed main circuit board. The portion mounted at 90° into the battery bay is the motor circuit board. 5. Remove the grey L-shaped trim strip. Note how the long end engages the black jack panel and sits over the cassette lid hinge. 6. Loosen the yellow/orange/red/brown YORB (motor rotation sensor) wires and the red and black (motor power wires) from the tape sticking them to the board. 7. Remove 2 chrome and 2 black screws that secure the main board to the chassis. 8. At one end of the main board is the black plastic tuner chassis. It includes the AM antenna. Photograph where they are arranged and loosen the tape holding the thin black and brown wires to the main board tape. Pull this tuner assembly off. It can dangle from the delicate AM wires but they can easily break off the main board. So take a photo of where they attach. 9. The battery spring is soldered to the main board and the metal chassis. Desolder the connection to the chassis only. Using a heat sink on the connection to the chassis will help inadvertently desoldering the connection to the main board. 10. Unscrew the two screws that secure the motor board to the chassis. 11. The battery plate or lid is soldered to the main board and screwed to a small metal and white plastic plate attached to the chassis. Remove its screw. The white plastic part of the plate includes a hidden pin that indexes into its small metal support plate. While lifting that corner of the main board, use a very thin pry tool to disengage the locating pin. This way you do not have to desolder the battery plate from the main board. * Reassembly step (D) 12. The YORB and red/black wires have to be fed toward the chassis, through the gap between the main board and the motor board. The motor board is surprisingly flexible, to a point, for clearance. * Reassembly step (C) * Reassembly step (E) 13. Start feeding the YORB wires through the gap between the boards. Tweezers are handy to pull or push on these wires. Work them toward the open end between the boards. When the wires have enough slack, unscrew the sensor board from the main board. Take a photo first, and be careful not to damage the tiny reed switch. The connections of the yellow and orange wires to the sensor are very delicate and commonly damaged when people work on these units. The consequence is the motor won't turn. *Reassembly step (B) 14. Once you have room, unplug the white YORB connector from the main board. The manual cautions against pulling on the wires to do this, but I was unable to do it without using the wires. * Reassembly step (A) 15. Now it should be possible to lift the main board far enough to get at the chassis to change the belt. The board may be stuck by tape, so work carefully and pry them apart if needed. Examine the exposed side of the board to locate two slide switches (S1 and S2) with silver cases and black knobs. Note or photograph the switch positions. S1, horizontal switch, should have the knob closest to the outside of the unit. Vertical S2 should be all the way up. 16. Since probably the belt is broken, check the manual or threads related to this for an image of how it is arranged. (Counterclockwise direction, starting with the motor, straight up to the outside of the rightmost of the two larger brass pulleys, under the smaller pulley between them, up and around the left large pulley, straight across to go over and around the remaining pulley and back down to the motor.) Ensure nothing is rubbing or hooked on the belt. Ensure the belt is not twisted between pulleys.) 17. If the old belt melted, which is typical, the remains have to be cleaned up using large numbers of cotton swabs and ample isopropyl alcohol. If they are melted, probably there is also corrosion or residue on the pulleys. They have to be carefully cleaned no matter how long it takes. This is a very messy job. I was able to reliably source belts from: https://fixyouraudio.com/product/belt-aiwa-hs-j09/ 18. If you are having tape direction or recording problems, it is possible S1 or S2 are corroded inside. Douse then with contact cleaner. Shield them so the spray doesn't get on other components, especially the pulleys or belt. I would advise to not clean them unless you are having rewind/reverse or recording problems. * Reassembly step (H) Reassembly Steps Work your way back through the disassembly steps in reverse order. Note these pitfalls, which are referenced in the disassembly sequence. (A) Reconnect the YORB connector before you run out of space to do so. (B) Attach the sensor board before you run out of space. As it disappears from view, check to ensure the orange and yellow wires are still attached. I added blobs of hardening goo to reinforce the delicate yellow and orange wire connections. (C) Maintain the wires in their YORB order so they lay flat without crossing. There is marginal clearance between the case and the main board and any wire crossings, especially over board components, can exceed that clearance. (D) Lower the main board until you have to pry the battery lid plate to reengage its index pin. At the same time the motor board has to be arranged on the inside of the two middle chassis tabs and outside where the two screw holes are. (E) Secure the wiring to the main board. Avoid wire crossings and overlapping board components. Ensure wires wrap around the edges of the main board via the notches. I cleaned off most of the original wiring tape because it had degraded. I used two types of double sided tape to replace it. One was carpet tape, for low clearance positions, because it is very thin. But it doesn't stick well. The other was double-sided foam automotive trim tape. It is designed to last forever, and is available in at least 2 thicknesses, 2 levels of stickiness, and a variety of widths. The thick stuff was too thick, and the stickier tape was too aggressive. You can use a paper hole punch to create tape "buttons". (F) There is a complication in replacing the chrome control panel. At the volume control end there is a metal tab protruding from the cassette bay. This tab tries to overlap the outside of the control panel. It has to go inside. But if you fit this side of the control panel first, the opposite side of the panel will jam against the head ribbon cable. Enough pressure on the ribbon cable will bend it and break traces where the traces connect to the main board. You will lose an audio channel, causing no end of trouble. So be extremely careful. Mount the cable or volume control side first and use a tool to position the metal tab on the other side. (G) By this time the radio tuner dial will need to be adjusted. Place the jack panel with the green tuner dial engaged with the white gears. Scroll to one end of the indicator travel, whichever end is within the window. Take the panel off and dial the long gear strip so it is near one end of travel. Mount it and scroll to both ends of the dial to see if you got it in the right position. Fine tune this process until the indicator equally lines up with the ends of the frequency scale. (H) Before testing the tape drive, MAKE SURE THE PAUSE SWITCH IS NOT ENGAGED.
