When I received this AIWA in the post the unit was one of those rare examples that still worked. However there were a few tell tale signs that all was not well inside.

Firstly there was a faint audio hum from the unit when made to play back a tape. It was was also a touch hungry and was eating the tape. Tape speed was not balanced on both sides of the cassette. The memory battery had also failed and the AIWA was not remembering the stations or time.

When I removed the screw from the back of the metal case I noticed some crusty deposits on the back of the screw head. Removing the rest of the screws to open the back cover reveals the usual crusty gooey mess I've come to expect from AIWAs of this vintage.

The capacitors were tested and interestingly only a few had not survived the aging process. Not surprisingly the three surface mount capacitors were dead. I have yet to ever find any surface mount capacitors on an AIWA circuit board in working condition. Of the three 220uF 4V through hole capacitors present, the horizontally mounted one was actually in very good condition. All the larger through hole and surface mount capacitors were removed and retested again. Only the 47uF and the 220uF 2V through hole capacitors are kept to be reused.

The volume pot, the switch board and the flat cables are removed.

The board is then given the usual cleaning treatment of IPA and sodium bicarbonate before being rinsed off and dried. The volume pot is also cleaned with CAIG DeoxIT D5 spray.

The capacitors are added to the cleaned board and the previously removed parts are reconnected.

The screws are removed from the door and the inner metal panel removed to reveal the tuner board. The opportunity is taken to clean all the door panel parts. The battery is a Panasonic CL-1220. These are no longer available so a substitute Panasonic ML-1220 is used instead.

The old battery is removed and the replacement fitted into its place.

The door is reassembled and re-attached to the main body of the JX30.

The take up reel is slipping and not spooling the tape slack, this in turn is causing playback instability and the tape to be eaten. The cause of this is a worn/slipping clutch plate. The clutch plate is hidden beneath two other components in the tape transport. The centre pulley wheel is removed, followed by another smaller cog to reveal the clutch plate. The clutch plate is removed and the two halves of the clutch plate separated. The felt part of the clutch is examined. There is minimal wear on the felt part, but there is enough grease on it to cause slippage. The felt is de-greased and the parts all reassembled.

Fully restored pictures can be found at index.php?board_oid=193392314111653483&content_oid=252082971018338708

*Grrr* the photos didn't upload first time!

Keep posting these- I find them very useful, even though now I rarely have internet access (that's why you won't see me around).

Hey hey ! I'm happy to see your job ! although not yet read all your post , there's something funny here , check my JX303 thread , so you did mount the 47uf 4v the opposite than they were originally !? And you didn't noticed the reverse polarity again for one of them like the pcb suggests it ? That's troubling me... Isn't there any polarity here ???

It does not surprise me that there is such an error on the screen printing. There are errors on the JL30/303 screen print as well. I make notes of the capacitor orientation along with their values before I remove them, since when I clean the board the screen print normally just floats off.

By sheer co-incidence I have the schematic diagram of the main PCB for the JX30/303, and the 47uF 4V capacitors are all used for noise suppression to ground, so in this particular case incorrect orientation would not have had a major detrimental effect.

It should be noted that electrolytic caps are way more forgiving than tantalums with reverse polarity, if tantalums were used then there could have been a VERY DETRIMENTAL effect ie fire or possible explosion. 

Hello Plop , thanks for telling me ! I was wondering if they were really used by the board (something like here but not used) ,now that you explain it's more clear. So would you recommend to put them in the same position ? Any incidence in my case you think ? I followed the board. Anyway nice job. It seems you did not took care of the one in the tuner , why ? I've checked(after) and i think i have that kind of capacitor at home , it's a 6,3 v but should be fine , i bought it at farnell's , don't know the purpose but not related to sound i imagine.

I'd recommend putting them in the orientation as per how you found them. You can confirm it is correct by carrying out a continuity test to ground for each contact.

IIRC, the 220uF 4V capacitor on the tuner board is for the power line noise suppression on the tuner logic IC. If it has failed testing then replace it. I haven't seen many of these fail at all. I too have some longer 220uF 6.3V which could be used as substitutes.

Ok thanks , i will replace one of them correctly then. The one in my tuner seems fine , no means to test it but looks fine.As i can see too you didn't follow the original polarity for the battery , as it of course does fit better , well it wasn't too difficult to work the pins ,what i did.