Repairing mid-'80's Aiwa HS-J09, 9, 600, 10, 36, 360

I've worked on a fraction of the number of players as many people here. But I found little expertise posted about the narrow range of Aiwa's that interest me. I'm hoping the things I've sorted out can help in fixing these models. And if it does make repairing them easier, maybe it can raise the profile of these units.

Like practically all personal cassette players, Aiwa's almost always have rotten belts. Other than that and some posts about fixing the auto reverse function, repair advice focuses on Sony.

I've worked on nine Aiwa HS-J9, J09 and J600 (which are the same except for TV audio reception on the J9), plus one each of J36, J360 and J10. They were bought as medium to worst condition units. I don't buy nice or costly ones.



These have very similar electronics and all use the Aiwa 2ME-7 mechanism. To help people doing searches find this thread, I'll include an imperfect list of the players I think use this mechanism.

My use of condition designations is that units that can play cassettes at a basic level are "repaired" or "working". I use "refurbished" for units that have all the parts and all the functions basically work. But not necessarily perfectly. Some cosmetic parts may be reproductions or non-standard (such as screws). The units I work on have some improvements over the original build.

To me, "restored" means having all OEM parts and functioning to at least original quality, which requires instrumented calibration. If they are also in perfect cosmetic condition I think they are called "museum quality". I don't consider my own work to be restoration.

Renewing the units has 3 aspects: cosmetic, mechanical and electronic.

Cosmetic can split into restoring finish, and replacing exterior parts. The idea of a player that is battered due to extensive use but internally restored to perfect function appeals to me far more than a cosmetically perfect shelf queen that doesn't work.

Electronic can be divided into physical matters like soldering, and calibration. Calibration can be done manually, or better, with special test tapes and diagnostic equipment. I don't own any of those things beyond a simple VOM, so I can't discuss that level of repair.

A stand with parts clamp holders, magnifier and light can be invaluable. And a decent soldering iron with a fine tip and adjustable heat. Knowing how to use supplementary solder flux and desoldering braid makes these jobs a lot easier.

Some of the wiring in these players is secured using black fabric or brown fibrous tape. These tapes dry out or become gooey. I didn't try to source either type. Instead I use foam double-sided trim tape made to attach logos and trim to cars. This stuff is designed to last forever, comes in all sorts of sizes, and a choice of tenacity. I've even used it to secure a couple of capacitors that were taller than the originals and had to be mounted on their sides.

Within the last year I have posted about repairing cosmetic issues. Links to those threads are just below. I have posted quite a bit on the "Walkman and Cassette player revival" Facebook group, but Facebook is a very poor archive medium. So I am contributing here to better archive this material.

- making trim parts for Aiwa's
https://www.stereo2go.com/forums/th...ilar-making-trim-parts-and-other-repairs.9347

- repairing my original Aiwa HS-J09
https://www.stereo2go.com/forums/threads/aiwa-hs-j09-repairing-2-units.9343/

- belt replacement
https://www.stereo2go.com/forums/threads/aiwa-hs-j09-hs-j600-etc-belt-replacement.9345/

- scratch and paint advice
https://www.stereo2go.com/forums/threads/scratch-and-paint.10304

My earlier Aiwa "cosmetic" posts in this forum were plagued by problems uploading photos so I couldn't include as many as I wanted. I hope to have less of that problem here.

This thread addresses the mechanical and "light" electronic repairs.

I will cover the following in separate posts and in some depth:

1. Equalizer
2. Gear assembly A
3. Erase head springs
4. Motor
5. Ribbon cable tears
6. Ribbon cable connections
7. Cassette detect levers
8. Main board soldering

And these as a group, with little detail:

9. Sw1 and 2 lube
10. SW 7 and 8 clean
11. Cracked battery solder joint
12. Cracked earphone jack solder
13. SW 1 and 2 solder
14. Volume control connections
15. Corroded wiring
16. Sensor wires
17. Takeup reel lint
18. Earphone jack corrosion
19. Switch damage and corrosion
20. AM antenna broken
21. Motor board damage

But first, some general notes.

Unless you are just replacing a belt, you should get a service manual. Maybe even for just the belt. These players almost never need only a belt. There may be a separate manual for the mechanism, which is the case here.

Beware that on models such as the J9, with TV audio reception, the Dolby switch also has the function of FM mono or stereo. So if you get FM mono but not stereo, the Dolby switch needs to be switched.

After a repair involving the tape transport, check the Pause switch before testing. I won't estimate how much time I've wasted trying to get the tape to play when the Pause switch was engaged.

I should mention capacitors. Repair advice for "walkmen" almost always recommends replacing all the capacitors. Many prospective repairers find this sufficiently daunting that some will be discouraged from starting repairs. Out of all these mid-'80's Aiwa units I have worked on, I've found only one definitely bad capacitor. It was on the Dolby board of the J36. I replaced two capacitors on my first J09, but it turned out that wasn't the problem.

The previous owner of another of my units had completely recapped it to solve a problem that turned out to be a flat ribbon cable defect. Unable to fix the unit, they unnecessarily gave up and sold it after going to the trouble of recapping.

Having said that, some will respond that unless you recap, the player will have degraded sound, hissing, squealing etc. I have not found that on any of mine. Of course, this applies only to this very narrow range of players. These few Aiwa models are known for their durable capacitors.

Then the response will be that such old capacitors are likely to fail soon. After 40 years?

Mechanism 2ME-7
HS-F150
HS-F160
HS-G09 same as G600, G9
HS-G9 same as G09, G600
HS G10 same as G101, G700
HS-G101 same as G10, G700
HS-G600 same as G9, G09
HS-G700 same as G10, G101
HS-J08 same as J500
HS-J09 same as J9, J600
HS-J9 same as J09, J600
HS-J09 same as J9, J609
HS-J10 same as J101, J700
HS-J35 same as J80, J350
HS-J36 same as J85, J360
HS-J45
HS-J50?
HS-J80 same as J35, J350
HS-J85 same as J36, J360
HS-J101 same as J10, J700
HS-J170
HS-J303
HS-J320
HS-J330
HS-J350 same as J35, J80, like J09
HS-J360 same as J36, J85, like J09
HS-J370 cheap version of J09
HS-J390
HS-J400?
HS-J500 same as J08
HS-J501?
HS-J505?
HS-J600 same as J9, J09
HS-J700 same as J10, J101
HS-J900
HS-JS185
HS-JS215
HS-315W?
HS-P08?
HS-P09 same as P600, P9
HS-P10 same as P101, P700
H-P101 same as P10, P700
HS-P600 same as P09, P9
HS-P700 same as P10, P101
HS-P09 same as P600, P9
HS-R9 same as T09, T600
HS-R10 same as T101, T700
HS-T09 same as T600, R9
HS-T27?
HS-T28?
HS-T75?
HS-T101 same as R10, T700
HS-T210?
HS-T290
HS-T303?
HS-T380?
HS-T600 same as T09, R9
HS-T700 same as T101, R10, like J10
HS-UV9 same as UV90
HS-UV90 same as UV9
Kenwood CP-303
Kenwood CP-707

 

Separating the Main Board

Most of these repairs require separating the main board from the mechanism. This involves many opportunities for damage. The biggest hazard is tearing the two flat ribbon cables. Tearing them is easy to do and very difficult to fix.

The board separation can be done without unsoldering either ribbon cable. But this is very risky because you have large parts dangling from the cables. The alternative is to unsolder the cables from the main board. This takes a level of expertise and entails some risk. Beware that often when you think you have a problem resolved and the unit assembled, testing exposes another issue, which in turn requires disassembling the player again. Every time you do this you have to repeat unsoldering/soldering the cables or risk damaging them.

(Disassemble and reassemble the units enough times and you will know from memory where each of the 12 different types of screws go.)

The risk of tearing the cables can be reduced by reinforcing them with strong tape while you work. Manipulating the parts can also cause breaks at the cable terminals. These can be hard to find.

A shortcut to avoid soldering is to remove the head. This requires first removing the Play button cover, which is hard to do without damaging it. The first time has the most resistance. With the (usually chrome) control panel removed first, the cover has to be popped and slid sideways about 2-3mm. Then it easily lifts straight up. Then you can remove the two head screws. If you break the button cover's tab, you can always glue the cover in place. Best to avoid that.

Of course removing the head means you have to adjust the azimuth when you replace it. It can be fairly well aligned just by lining it up with the bracket it mounts to. You should at least adjust it by ear, which can be quite accurate. Even better, use a visual display like Audacity. You want equal volume in the two channels at the same time as getting the most treble without losing the bass. Ideally this is done with an instrument and test tape. Oh...and removing the head is complicated by Aiwa's annoying habit of filling the head of the screw with hard black glue. The jury is still out whether you should secure the head screws with glue. I usually do, but not always.

The next complication to separating the main board is the 4 (yellow, orange, red, brown) sensor wires. They can be loosened from the mounting tape. At this point you can remove the two black and two chrome screws securing the board to the radio bracket and the chassis. I think you have to remove the black plastic AM antenna holder, in order to disengage the tuner shaft. Beware the smaller gear is not attached and you have a big problem if you lose it.

Either now or soon, desolder the connections between the motor board and the main board, or remove the two screws attaching the motor board to the chassis. The sensor wires can now be slackened off enough to unplug the white connector for the sensor wires. You aren't supposed to pull on the wires to unplug it, but I have never gotten it off without doing so and have never damaged this wiring.

Now the parts that connect the negative battery terminal to the main board. This includes the metal flap for the battery lid. There is a screw to remove. The white plastic bracket also has an index pin. You can either unsolder the connection, or pry the plastic bracket to disengage the pin. Doing this many times risks breaking the solder connection.

Around here you should be able to fold the main board away from the chassis. But if you haven't desoldered it, the only connection between them now is the equalizer flat ribbon cable and the motor wires. You have to be extremely cautious not to damage the ribbon cable. You may at this point have the radio bracket dangling from the AM antenna wires. You should have a photo of where they solder to the main board. Those points vary even between the J9 and 600/09.

The black/red motor wires can be left connected. The sensor wires can be threaded through the gap between the main board and the motor board. The thing motor board can be bent enough to do this. You can also unscrew the sensor with the 4 wires attached, after you get clearance for a screwdriver.

When reassembling, make sure switches 1 & 2 are in their default positions and that the sensor wires connector is plugged back in as soon as you can do it. Solder the motor board back to the main board with both boards screwed properly in place.

Threading the sensor wires back behind the motor board has to be the worst pain in the ass on these units. It is an utterly crude arrangement. And if you don't get them fully in place they can displace the motor board and so interfere with inserting the batteries. Doing this a zillion times does not make it any easier.

Make sure there are no components or wires on top of each other high enough to push up the back cover. Make sure there are no wires being squashed by the spacing knobs inside the back cover. Especially near the upper right screw. Make sure the motor wires are nowhere near the belt or motor pulley.

 

Handling Tiny Components

First, the screws. These players have many different ones and effort is required to track which type goes where. For example, some of the case panel screws look just like the screws securing the control panel. They are not the same. The control panel screws have a shoulder that the case screws don't have. The shoulder style screw is also used to attach the cassette door to the chassis. But that screw is not chromed. So figure out a method to track which screw goes where.

Many repairs require removing some of the brass pulleys. The pulleys are also easier to clean if you remove them. There's one pulley I never remove because it's too difficult. Depending on the model the pulleys are secured by e-clips or miniscule grey plastic snap washers.

When removing these things, have two tools, or a tool and a fingernail on them all the time. They snap free with enough energy to fly farther than a metre. Finding them can be impossible. They also disappear inside the mechanism, never to be seen again.

There are e-clip removal tools. I don't have one. To remove e-clips I use a tiny screwdriver on the open side and my finger on the other side. For reinstalling I push against the closed side and guard the clip with a finger. Luckily you can buy these clips.

The plastic clips are a bigger problem. I've settled on prying them off the shaft with the blade tip of a box cutter knife on the side away from the split. And with another tool or fingernail pressing to contain them when they suddenly snap off the spindle. You have to be careful not to damage the washer under the clip. So far as I know you can't buy these clips.

Note that each of the pulleys has a washer on both sides of the hole/bushing through the chassis. The spacing of the pulleys is critical, so care has to be taken to not lose any of these. Though you can make replacements out of thin plastic.

The earlier production units with the belt clip fittings use e-clips on two of the four pulleys, while later production used split plastic washers on all of them. It does mean you can substitute e-clips if you lose the split washers.

To handle the clips and washers once disengaged, I wet a fingertip and touch them. Using tweezers risks dropping them or them popping out and disappearing.

The e-clips press back on from the side of the spindle. The best way to reinstall the plastic clips is to press them down with a wetted finger, and fingernail or pointy tool, over the top of the pulley spindle. And then slide them down the shaft with even pressure on two sides until they engage their groove.

As I expose the mechanism, I put a bit of glue on one end of the smaller springs. This allows them to be disengaged, maintains where they came from, their positioning, and prevents losing them.

 

1. Equalizer

A bad equalizer can prevent both radio and tape audio or one channel, or, with some sliders in some positions, some audio.

I think a bad equalizer could be bypassed by shorting the right and left channels at the main board connection for the equalizer flat ribbon cables. But I don't know if there are risks besides obviously losing the equalizer function, and I have not done this.

The 12 metal tabs holding the equalizer to the equalizer board can be pried straight. The metal shell of the equalizer then comes off, exposing the loose parts underneath. The only electronic component is the graphite traces bonded to the board. These are just potentiometers. The real sound alteration happens in the adjacent IC's.

Each slider has 4 delicate plastic tabs, and great care has to be taken not to break them. Each slider has 4 metal prongs that rub along the embossed traces, and a 5th prong that only functions to mechanically engage with the holes in the metal shell. This provides a haptic dedent at the neutral position.

Delicately clean the traces with a swab wetted with isopropyl alcohol. Don't rub hard enough to remove trace material. I've had mixed success doing this, restoring function in some cases and not at all in one case.

I also scrape off the contact points for the 4 active prongs on each slider. If any of the prongs have been flattened, I carefully bend them back so they engage the traces.

When reassembling make sure the 5th prong engages the holes in the shell, and be very very careful to line up the sliders so no delicate corner tabs get broken off. Broken tabs means the sliders won't track straight.

 

2. Gear assembly A

The symptom is that auto reverse doesn't work. Auto reverse failure can also be caused by:
- dirty leaf switches #7 & 8
- faulty switches #1 & 2
- the pivot plate holding the 2 partial gears needing lubrication with respect to the chassis
- the main board has been attached to the mechanism with switch #1 in the wrong position. This will also cause music to be played backwards.

This requires removing the main board, the belt and two of the brass pulleys.

Then you can remove the e-clip holding gear assembly A, visible as the large white gear. Be careful because the assembly should be spring-loaded.

Gear assembly A has 5 parts. The small gear C must be fixed with respect to large gear A. Gear B can turn independently but with friction from the spring pressing it against the felt washer. I still don't fully understand how this works as a clutch.

Gear C is fixed to a post on gear A using a very tight press fit. Of course this causes huge tension on the barrel of gear C. And over time, it splits. Auto reverse won't work until it is fixed or replaced. I have heard later units such as the J10/36/360 have an improvement that solved this failure. While I can't see any difference, those 3 have arrived with gear C intact. I did this repair on them anyway.

There is a YouTube video** of someone fixing gear C on an HS-G600. While I admire their setup and expertise, I don't like their repair. They demonstrate how to glue the crack on gear C. Given the forces present were sufficient to crack intact plastic, I don't see how a glued crack is going to last very long. The first and only time I tried glueing the crack, it failed immediately.

My method is to carefully scrape down the sides of the post on gear A so that the stress on the barrel of gear C is reduced but not eliminated. I then put the assembly together with the mating surfaces of gear A and C epoxied. I mount the assembly on the spindle with the e-clip to achieve the correct spacing of the components, before the epoxy sets. Apply the glue very sparingly or you will bond gear B to gear A.

I have had reason to take this apart after the epoxy has fully hardened, and I cracked the gears apart by putting the assembly in a vise and applying pressure. Putting pliers on gear C to rotate it will only cause unfixable damage to the teeth.

I found one gear A with a long crack. I fixed it with glue, but it was also warped. So it was never going to work 100% and I replaced it with the gear from my donor unit.

**(
Though very helpful, this video is flawed.
- the black trim panel inside the cassette bay does not have to be removed for this repair.
- only the two brass pulleys overlapping gear assembly A need to be removed, not three pulleys.
- each pulley has a washer on both sides. The rubbing sound the author did not resolve at the end of the video was because he did not have or reinstall all the washers. This would throw off the pulley spacing.
- as I said earlier, I don't think this repair will last.)

 

3. Erase head springs

The symptom of this is that the Play button jams halfway down. And rewind and fast forward are unreliable. To further diagnose it, remove the chrome control panel. If there are one or two spring ends sticking up near the tape direction indicators, this repair is required. If you see a unit for sale with the Play button halfway down, it has this problem. I buy mid to low condition players, and most of them have this problem. I didn't know what the problem was, and at first just resigned myself to those players having this unrepaired flaw. But after I got a scrap unit, I figured out the problem and how to fix it. I then went back and fixed all the players affected by this.

This requires removing the main board, the belt, three of the brass pulleys, gear assembly A, much of the mechanism, and the head.

This took me quite a while the first time, using the 2ME-7 service manual and carefully photographing and documenting everything I did. By the 5th one I could have it apart and reassembled in an hour, without using documentation.

The problem is that there are tiny tabs that are part of the black molded plastic erase head carrier, officially called the tape guide. These tabs retain springs that are essential to guiding the erase heads as the head carriage engages and disengages. When the springs are out of place, the erase heads jam, which in turn jams the head movement and the Play button.

Several layers of the mechanism have to be removed. I call these "plates" but the official term is "levers". They come out in a certain order and I put them aside in that order, with the clips etc. taped where they came from. Several springs have to be removed and they must go back exactly where they came from and the right way around. Or they will come off or scrape on a pulley or the belt.

As I expose the mechanism, I put a bit of glue on one end of the smaller springs. This allows them to be disengaged, maintains their orientation, where they came from, and prevents losing them.

The two deeper levers can be manipulated out of the way without fully removing them.

Finally there is access to the two screws that hold the tape guide to the chassis. Remove them and the tape guide. The roller arm, retainer, erase head and spring can now be removed.

I use a hammer to flatten a cut off, straight dressmaking pin. I then use a sharpening stone to fashion the end into a drill shape. This isn't as good as a real drill, but it suffices for plastic. I drill a hole near where the tab broke off.

I then cut a piece of straight pin. This has to be long enough to go through the side of the tape guide and retain the spring, but not so long as to be unable to pass the end of the spring past the pin. With the right length, I epoxy it in the hole I drilled, taking care to ensure it is flush with the tape guide's mounting surface.

After the glue cures I reassemble the erase head parts. The last step is to get the spring end past and in place under the new pin.

Then reassemble this whole sequence of parts. You can oil them or use very light grease as you go.

This repair is far stronger than the original flimsy arrangement and will be permanent. Proper operation of the buttons is now very satisfying.


Illustration of mechanism plates removed in order, with fasteners taped at installation locations.

Retainer tab present and broken with spring end free.

Drill made from straight pin

Finished pin with spring in place.

 

4. Motor repair

This requires removing the main board, the belt, and desoldering the motor board.

The motor has a small hole in its case that looks like an oil port. It is not. It does not go through. I don't know how to lubricate the motor other than soaking it in oil or disassembling it. It is not designed for disassembly. Yet corrosion from rotting batteries seems to easily find its way inside the motor.

First, pry the belt pulley off the spindle. This is a press fit that will get looser every time you remove it.

I filed out the dimples in the case to separate the cover part. I also had to bend the metal between the filed grooves. Then there are several layers of round metal plates. Some are held in place by the motor magnets. You have to carefully document the order of these plates and which side is up or down. Some take force to pry apart. The corrosion doesn't help.

There are some hair-sized wire brushes in the commutator. Carefully record how they are arranged before you remove these parts, and how the two wires thread through the plates. These brushes are EXTREMELY easy to damage. Anything you wreck means the motor is a write-off.

I thoroughly cleaned all the corrosion out of the motor. Putting it back together properly required several attempts, and in the meantime the pulley became loose on the shaft. My attempt to tighten the fitting by impacting the end of the shaft resulted in damaging something inside so that the free rotation I had achieved, was no longer free. So the repair was wasted. Next time I would use thread locker to attach the pulley to the shaft.

 

5. Ribbon cable tears

These players have flat ribbon cables for the head and another for the equalizer. They are a total nuisance when doing repairs. They are very easily damaged and very difficult to repair. A person I contacted who does SMD repairs simply refused to touch them. These cables are impossible to obtain except from donor units. And equalizer cable in my donor unit was rotten beyond use.

Desoldering them from the main board as part of the repair sequence greatly lowers the chance of damaging them. But at the cost of the extra work and risk of damaging them while soldering. Remember the rule of not applying the iron to the work for more than 2 seconds.

There is a YouTube video of someone repairing them. That person succeeded in neatly bridging the breaks using only solder. I've been unable to accomplish that and I have to use jumper wires instead.

The simplest way is to jumper between the terminal connection points of the ends of the cable. The damaged cable can be used as a base guide, and the repair supported with durable tape such as fiberglass reinforced tape.

The next and more presentable repair is to solder jumpers made from thin transformer winding wire, across the breaks. This wire has a fairly tough insulating coating, as it must have. Staggering or separating the points where the jumpers connect to the traces lowers the chances of inadvertently loosening one while you heat an adjacent wire. Which will happen if the connections are beside each other.

Choose the solder points and scrape the coating on the flat cable until about 2mm of trace is exposed. Using flux and solder, get a bit of solder to adhere to the exposed trace. Prepare the jumpers by baring and tinning the ends to get a bit of solder on the ends. Then it's easier to get the wire end to solder to the trace. This is still finicky work at best, but the more you do the better you'll get at it. Done properly the connections are very secure. Done improperly they will look ok but soon come apart.

So be sure to check for continuity before reassembly. Consider reinforcing the repaired area with sturdy tape.

 

6. Ribbon cable connections

Many of these players have broken or cracked flat ribbon cable terminals. Every time the Play button is pressed, the head ribbon cable is flexed where it attaches to the head. Every time you move parts around while doing repairs, ends of the cables are flexed. Sooner or later a trace or connection will break. Some models have a brace for the head cable, but this only changes where the flexing happens.

This is the place to note that improperly replacing the control panel can jam against the head cable where it attaches to the main board, and damage the cable. The cable must be flat against the board.

Cracked traces show up as loss of one or both channels. Equalizer cable breaks will affect both the radio and playing tapes. Head cable breaks will affect only tape playback. Because these breaks typically are not visible, continuity checking is the go-to approach for finding them.

 

7. Cassette detect levers corrosion

This requires removing the main board from the chassis, and disengaging springs attached to the levers.

This is why the record button won't work on the players that record.

The Aiwa 2ME-7 usually has levers to detect inserted cassettes, and on units that record, levers to detect the no-write tab state of prerecorded cassettes.
These levers are right next to internal battery compartments, and one of the first areas to be invaded by battery corrosion. You can see one end of the levers in the bottom of the cassette bay.

There are two corrosion problems. One is that the sliding or pivoting levers get stuck due to corrosion between them and the chassis.

And when you go to fix that you find the levers are attached to the chassis not with e-clips, but with press-fit brass fittings that also provide the pivot friction. You can make the fitting to rotate in the hole in the chassis, but the proper fix is to have the lever rotate with respect to the brass fitting.

The solution I worked out on the donor unit is to lightly hammer out the brass fitting from the other side of the chassis. Then you can separate the parts and remove all the corrosion. Reassemble and gently impact a small centre punch or equivalent to resecure the brass fitting to the chassis. Don't overdo the hammering. Replace the springs and oil it. The levers must move freely with only the spring tension.

The stuck levers are circled in red in the photo. The corroded brass pivots are circled in purple.

 

8. Main board soldering

I have found broken or "cold" solder joints in all sorts of places on the main boards in these players. A bad capacitor had fallen off the Dolby board of the J10. An inductor had broken off next to the earphone jack in the J10. A couple of invisible breakages of a diode from a motor board in a J9.

On one of my units, switches Sw1 & 2 were not soldered properly to the main board. This appeared to be a factory defect. It may have passed quality checking, but probably never worked properly and so the unit has almost no wear. It's amazing it was never just thrown out.

Besides using the circuit diagrams to check for continuity, you can also use the rare voltage specifications to locate problems. The alternatives are very careful visual inspection, using something like a toothpick to poke at things with the unit powered up, and as a last resort, swapping components with known good ones.

 

9. Sw1 & 2 lube

A simple matter of spraying contact cleaner/lubricant into them and thoroughly exercising them. Shielding the switches before spraying avoids getting lubricant all over the place. Especially avoid spraying lubricant on the belt or pulleys. Make sure the switches are in their default positions before reassembly. Or you will be sorry.


10. SW 7 and 8 clean

These are the leaf switches activated by the forward and reverse buttons. I found I had to carefully scrape off their touch points on a couple of players. The J36 has more robust versions of these switches.


11. Cracked battery solder joint

This is where the white plastic bracket attachment and the negative battery terminal lid solder to the main board.


12. Cracked earphone jack solder

The earphone jack is subject to a lot of bending forces that can break its three solder connections. The wires attached to these solder points can also get broken.


13. SW 1 and 2 solder

Fwd/rev and Play/record switches can be improperly soldered to the main board at the factory.


14. Volume control connections

The solder connections for the volume control are subject to bending forces because the connections are how the control mounts in the unit. They can look fine but the tiny rivets holding the connectors onto the body of the control can work loose. Reflowing the solder and some spreading force on the rivet heads should fix it. The only compatible replacement I could find had a slightly different pin arrangement that required using jumper wires.


15. Corroded wiring

Corrosion can rot wiring connections. If the player has corrosion around any wiring ends, those connections have to be very carefully checked.


16. Sensor wires

This mechanism has a gear with a strobe pattern. There are 4 wires attached to the sensor for that gear, and the wires can be broken off the sensor when the unit is serviced. This will prevent the motor from running. The breaks can be hidden under the black glue.


17. Takeup reel lint

Pull the caps off the takeup reels to check for lint, hair etc. wound around the spindles. Take care not to lose the springs and line the caps up to the flats on the spindles when reinstalling.


18. Earphone jack corrosion

This is common. Desolder the 3 connections to the main board and either replace the jack, or carefully push out the brass components and clean them. They may require bending to get proper contact with the earphone plug. Especially the one in the bottom of the jack. I used a spare male 3.5mm stereo jack to check for continuity through the female half.



19. Switch damage and corrosion

The little slide switches can be corroded or broken. Replacements are available with different contact layouts and knob vs pin arrangements. Disassembling them for cleaning is relatively easy. My attempt to fix a crushed switch was a waste of time. Unfortunately like a lot of this stuff, to get one you have to buy a bunch of them. On the other hand these things are cheap.

Photo of a corroded and disassembled switch, with a new replacement.



20. AM antenna broken

Unless it is really smashed, a cracked ferrite core can be epoxied back together and braced while it cures. The tighter the broken ends are pressed together, the better. This doesn't seem to degrade the antenna's performance as it functions as a magnetic field, not a conductor.

21. Motor board damage

Occasionally there will be damage to the separate motor board. Usually caused by corrosion since it is adjacent to the battery compartment. Unfortunately the service manual does not have a circuit diagram for the motor board. I made a substitute by photographing both sides of the board, zooming in on them, flipping the image of one side, and printing it out. This allowed the needed continuity checking.

 

A tremendous guide and help to all those that will undoubtedly find this in the coming years! This is an impressive effort of itemization and description for these repairs.

 

I added a description and link to this thread on the https://walkman.land/aiwa/hs-j900 page.

 

Excellent idea to add the link. I have earlier posts that document cosmetic repairs such as making knobs.

 

Added the link to the common problems thread: https://stereo2go.com/forums/threads/list-of-walkman-portable-recorders-common-problems.7535/page-3
However it's to be mentioned the models list should be revised. There are some walkmans which for sure don't use the 2ME-7 mechanism (P202, PC202, P20, P30, etc.), while on others I'm not sure.
Judging by the buttons outside, the 2ME-7 will look very similar to the Alpha-1 mechanism but in reality they're completely different mechanisms.

Wanted to do a post myself regarding the Alpha-1 models, but don't have a complete list at the moment.

Please add the links to those repairs here also, so they're more visible.

 

Thank you. I have a quad of HSJ202 corpses - with battery gondola and vinyl case - waiting for reanimation.

 

Super valuable post. Thanks so much. Wondering if you have any permanent fixes for the jamming of the mechanism on G8 and J08 units. You can have them repaired and working fine on bench testing but eventually that pulsing problem starts again once reassembly completed. This is the biggest issue with these soft touch full logic Aiwas whereby you cannot stop the player because the head cannot retract or move fully into the play position. Taking the batteries out doesn't resolve it either. With the HS-J08 it requires full tear down again to get it to stop pulsing.
Cheers
bd

 

Thank you. I appreciate anything that improves the quality of the advice I offered. I removed from my list of models with the 2ME-7 mechanism, all the models that are listed on the Alpha mechanism manual. I suspect at least several more with Alpha mechanisms should likewise not be in my list.

I'll add a post with links to my cosmetic repairs threads.

 

Silverera,
I don't know if the G08 uses the 2ME-7 mechanism under the soft touch controls. If it does, I suspect one of the erase heads is jamming due to a loose spring that retracts the erase heads carrier. This probably would jam the head retraction system.

If so, and you can remove the panel covering that part of the insides, look for a spring end sticking up that looks out of place.