After seeing plop's great tutorials, I decided to go ahead and try re-capping my JX707.

While waiting for the new caps to arrive, I removed the cruddy old caps, cleaned the board and tested the board using whatever capacitors I had lying around. (As you can see, the 220uf Elnas I had were way too large.) At this stage everything was working again. Playback on forward mode however was a little slow.

I used 6.3v Chemicon MVA(100,47uf) MVY(220uf) series caps for the JX707, of which links are available in plop's thread. Instead of using through hole 220 caps for the 2 caps on the right, I removed the plastic base and trimmed the legs of the SMT 220uf caps to fit. This makes them slightly shorter.

At this point I lubricated all gears related to forward playback and put the whole thing back together. First impressions are great: everything works, all the new caps fit.

Edit: Azimuth seems to be a little off in Fwd direction. on closer inspection one of the guides on the reverse pinch roller assembly is missing. Checked with my parts unit JX70 and the same part was broken as well.

As you can see I'm missing the original external battery pack, so for now it runs from a wired battery pack until I somehow find one.

Nice one. Glad my threads are of some use to you.

I have an example that plays in FWD at the correct speed, but in REV is fast. In my example I think maybe the pinch rollers are not making good contact with the capstan and the pick up reel is doing all the work.

It is not possible to adjust azimuth on this model, especially now that I've discovered you need special tools to remove the head from the head assembly block.

That could very well be the cause. Should I find another unit to swap parts with I'll just simply swap the whole head/pinch roller assembly over (not too hard to remove). This should fix any pinch roller issues on both directions (theoretically).

Hello bub,

you wrote, that you lubricated all the gears. What did you use for that? Some parts are metal others are plastic. Did you use the same lube for both materials or different?

Thanks

kerni99

I use sewing machine oil for metal/shafts/washers and Tamiya grease for plastic gear teeth.

Sadly I still cannot use this unit because of the parts I need, so I cannot compare it to my 505...

Would you mind posting a photo of the mechanics please ? Can't find one... I will receive a JX707 soon and i suppose it has a belt issue. That's what seller says :

Radio works perfect in this player, but cassette functions  do not work  well, cassette plays to FWD side well and F FWD function works well too, but to REW side cassette sometimes plays well , but sometimes plays couple seconds and stops, same problem with REW function. Screen works perfect too.

Same behaviour as my JX849 so i suppose this is just the belt , and i wonder if it's not the same mechanics inside so it would be the same belt ?

OF course only if you have or someone else.

From the seller's description, I would interpret that to be an issue with the belt.

This unit will require desoldering to get at the belt. You need to be very careful when desoldering the solenoid parts on this model as they are easy to melt/destroy. I rate this as one of the harder AIWAs to service on account of this issue with the solenoids.

I don't mind since i succesfully opened/closed my JX849 that requires 17 sold/unsold -ering points !

The hardest thing is to remove the board ,i use a pump and it's hard to remove all the solder ,i use a little screw driver to lift the board while trying to melt the solder where it wouldn't go away ,the board is very thin ,i really wonder if the hot air wouldn't be the right solution ? Since plastic parts are under the board and hot air is very quick , yet it depends of the flex cables location unless i remove them of course.How do you remove all the solder ? Don't you have some solder that won't come like me ? What kind of tool do you use ?

The problem is the old solder used on the JX707. It does not flow very well. You have to make sure that all traces of the solder is removed from the solenoid before lifting the board, otherwise you lift the binding post away from the solenoid body. When this happens you also break the very fine copper winding wire as well - ruining the solenoid. I have a few second-hand JX707 where this has happened. The soldering points are deceptive as they are on both sides of the board. So you may think that all solder has been removed from the top view, however it could still be attached underneath!

You have to remove as much of the old solder as possible. Apply new solder to hopefully mix with the old solder. Remove this mixture of old and new solder. All the time careful not to apply too much heat to deform the solenoid and freeing the binding post from it.

Hot air won't help you here. there are soft plastic components nearby. It is a very crowded part of the board. Plus, you risk dropping parts off underneath as the board is quite thin. What would help is a continuous desolder vacuum station. With that you can suck up as much of the melted solder as possible before it has a chance to solidify again.

BTW - It is possible to lift the main PCB board without desoldering the control switch PCB. Just be sure to remove the two screws from the control switch board and freeing the microswitches before carefully lifting. If you do decide to desolder the control PCB, resoldering it to the main PCB later can be a pain to get the pieces to contact together correctly.

When I work on this part of the JX707, I try and do as much of the servicing as I need to (ie new capacitors, new belt, lubricate dry gears, check and tighten hinge screws), as it is so much trouble to service the unit.

I use roisin impregnated solder wick braid. I use the finest grade as this is best suited for SMD work.

Chem-wik(R) size 0.030 2-25L

Part number 770-424-4888 for 7.5m/25ft

The roisin helps with wicking away the molten solder from the components and also acts as a heat sink.

When I first started reworking PCBs I found that I always needed a third hand to use a vacuum hand pump. Plus when working with small SMD components I found that I would end up sucking them off the board completely which was why I swapped to using solder wick braid.

For Autoreverse issues, also check the autoreverse switches inside. Mine would not go into reverse mode properly until I cleaned the switches.

And YES, WATCH OUT for the solenoid. The JX849 solenoid is much tougher than the one in the 707. (I use solder wick too). (707 is much more fragile than those 849 series)

I recommend desoldering the button pcb, much easier to remove with less chance of damage. For testing, solder on some extension wires.

In more news mine is still unusable: still needs battery holder, pinch roller assembly and now a volume rheostat.

Thanks for the advices guys. You're right ,the board is too thin for hot air... I'm yet very careful. No one has taken some photos of the inside ? I'd really like to see what we're talking about.

No one has thought about a solution to avoid soldering/desoldering over again for future maintenance ? Couldn't we use very small wires(yet very hard to find) or customizable flex cable ?

The ideal method will be to do the best you could and close it up. One method i use is using as little solder possible to form a good seal, so it will be easier to desolder later.

I keep meaning to do a strip down tutorial of a JX707, seeing it is one of the most difficult to take apart. However I have a neverending stack of AIWA with capacitors that need replacing, and these take priority I am afraid.

What parts of the inside of the JX707 are you looking photos for? There are quite a lot of photos internally of the JX707 on this forum already.

I'd like to see under the board and the mechanics ,and see what that solenoid looks like. All i've found are photos of the external.

You are lucky I have one partially disassembled. So here are a couple of photos from it.

Incidentally, this is one of the second hand badly repaired units with a broken copper wire on the solenoid.

Soon I will be recapping a power supply for a 32" lcd tv. I ordered all the caps from www.digikey.com The guy up the street gave it to me. Said its been dead for some time. I think I may use it as a computer monitor. I looked up the issue online and this model is known for the issue. It said to replace them with a little higher voltage caps so I ordered them. I also bought high temp longer life caps.

@Plop:thanks for the photos ! Nothing common with the JX849 mechanics albeit there seems to be common parts.I just can't figure why the big solenoid would be more fragile than the small one ,that last seems those in the JX849.

The problem with the "big" solenoid is the plastic that is used to mount the binding posts for the copper winding wire. It is not heat resistive and goes soft when heat is applied to the binding posts. This is made worse by the fact that there is not much of this plastic round where the binding posts are, further increasing the likelihood of it melting.

The only part common with the 849 series is the type of motor used. And plop is right on the solenoid. Once broken, repair is possible but difficult.

The 849 series is actually very tough when it comes to desoldering- they were the very first machine I worked with and I was rather crap at soldering at the time, and I never really broke a trace despite opening and closing them so many times.

Oh god ! How way more easy it is to use roisin impregnated solder wick braid !!! I have some , don't know if it's "impregnated" or not but using it after the pump is a lot of help Mine is called solder sucking wick.

edit:easier in fact ,finally for the motor this time i used the the long tip to desolder it ll at a time ,i will order some "impregnated".

Just have received a JX707 and you know what ? It reminds me of the JX505 ! Not to say it's bad ,just have tried the radio but... there is so much better in term of sound beleive me ! The sound isn't weak so i suppose caps are not completely dead. I retreive that flat sound not bad but nothing compared with the JX303 or the even better JX849.I'm sure these sounds identical(505 and 707) ,i'll  tell you when i put my hands on a 505.Inside it says amorphous head ,well same head as 849 but not same head as 303 wich is HX... It's a soon feedback of course but i know how sounds the others.Yet cool female voice ,very fun.

edit:is it the direct successor to the 505 ? So i wouldn't be surprised.

Cosmos,

From what you describe, it comes across as though there is an issue with the unit you have received. Soundwise the JX707 isn't the best that AIWA has to offer, but the sound nonetheless on a good example should be quite acceptable. The weakest point of the sound is the DSL on this model, as I think the DSL circuitry used is not a good implementation as the automatic bass level control over and under compensates at the most inappropriate situations. Otherwise there is a good stereo sound stage and dynamic range. There are also quality control issues with some examples where the tape transport has not been manufactured correctly. I have some that exhibit abnormal tape wear on the play/record head. This has affected the playback sound quality, which in turn caused me to perform a HX head transplant. After the head exchange, the sound quality was greatly improved. There is a post on this forum about that.

I think i was in fact too categoric ,as i said it was a quick feedback ,in fact it sounds pretty good ,it just sounds different,a bit less bass than my other JX ,just the time to get used to it and you should love it. Or may be i've waken up some caps... Anyway a nice little unit , i'll have to change the belt because the reverse playback and record function don't work very well ,we'll see that later.

You know what ? Now i love it ! I find the sound better than my 303 (yet not fully recapped) ,i think some caps have come back from long sleep.This unit is really nice finally.I should soon receive a JX505 ! I must admit that back in the days i hadn't a good headset.

edit:by the way , does it share the same belt as the 849 series ?

I'm sure you will find a good 505 to not disappoint you vs the 849.

505 uses a larger belt than 849 series.

I paid the price for my future 505 , 106 euro shipping incl. from Germany ,there's no box but the pouch , the power supply station and the remote ,the seller told me it has no issue at all. I now love my little 707 ,it's so beautiful and it now sound pretty good ,i suppose the caps needed a little power they surely missed for years. I was talking about the 707 belt , i suppose the 505 don't need a new belt. Later i'll show photos from my PX747 , i don't know why but mechanics in this one is really strong ,i still see the fresh grease , got it for only 5 euro(excl. shipping) with remote and battery pack ,the lead acid battery still have some very little power inside but not enough of course to move anaything , strange that it's not the same you find in the 849 ,capacity is double the pb-s5 and a little larger.  

I think when you get the JX505 (and it is a good example JX505), you will like it over the JX707. I have to say between the two, I prefer the JX505, especially with the deep bass mod. and DSL enabled on my 2nd JX505 it is heaven to listen to on bass hungry open ear headphones.

Do you know if you've managed to buy an older JX505 with the bi-azimuth mechanism?

I'll give a little feedback when it'll be home.I can't tell now  about the head ,i didn't know there were two revision of the 505 ? Keep in mind multiple factors when i talk about the 505 , first i stepped from a J08 to a JX505 , J08 as it had no bass boost was may be more punchy on basses ,i had back in the days the very standard headset ,so with units with enough bass(i don't like the bass enhancement functions) it's OK , i think that some units reveals themselves with better quality headsets with larger bandwidth.They seems to sound all different don't you think ?

Yes there are two versions. Read this thread for more information index.php?board_oid=193392314111653483&content_oid=215770785222165810

I agree, no two models would sound exactly the same. Some are more bass heavy, some very neutral and some quite bright. This is of course if using the same pair of neutral response headphones.

Having a good dynamic range also helps. Thankfully since I am only really interested in high end AIWA from the early 90s, most of these have a good dynamic range. Dynamic range can be further extended lower by replacing with higher valued DC blocking capacitors as I have done with one of my JX505. Doing this mod does not increase the level of bass.

I think I found your JX505 on eBay Germany. If it is the one that I think it is, then according to the photos it is a newer JX505 with the fixed azimuth.

€106 is a high price to pay, but then you have got one that hopefully does not need any additional work to it.

Yes you surely have seen my buy it now. I placed a 89 euro bid instead of the 150 asked for BIN and i did well. Yes , closely looking at the picture it seems to be a fixed head but i'm not to worry since that kind of transport has nothing to see with the (for example) old J08 wich clearly was hard to align.Yes it's a may be a high price for it but when you see:

http://www.ebay.de/itm/110743377191?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

and especially read the description(or translate)...^^ I have no regret about the other alive unit.And it comes complete with the carry case wich is rare.

I've checked my JX303 and it has that bi-azimuth system ,my 707 and 849 don't ,but i repeat the "new" head transport is very good.

When i was talking about sounding different i meant between various models not same models , my two JX849 sound the same yet you can hear a little difference between old caps and new caps.

That seller does seem to my mind have a reputation for inflating his prices on eBay. I certainly would not have accepted his BIN price of €150 for the JX505. I paid a lot less for a boxed JX505, and that was just last year.

The other JX505 went for a good price, but the price reflects the lack of accessories.

The JX303 is an older unit and came out before the JX505. The JX505 was manufactured during the time that AIWA swapped over from the bi-azimuth to the fixed azimuth. Hence why there are earlier models with bi-azimuth and newer with the fixed.

The newer 0ZM tape transport as found on the JX707 is ok. On good examples the playback is quite acceptable, on models where it is badly put together you get mis-aligned heads which in particular to the JX707 cannot be readjusted unless you have special tool to remove the bolts and adjust for poor installation of the head. Otherwise you get one side with perfect alignment and reverse side out of alignment. Also separately I have seen some with irregular head wear also due to poor head manufacture. The tape guides in the newer transport is integrated into the pinch roller assembly and is easily broken off when cleaning or by abuse. If the tape guides break off, then you get playback speed issues arising. Maintenance of the 0ZM transport is also a hassle as you need to desolder to get inside, whereas the older ALP transport as found on the JX303 and JX505 only requires the removal of screws get access to the belt and gears.

Yes, I too was talking about the variations of the default sound from different models. For example I find the PC202 is very neutral or transparent sounding, the PX505 is slightly bright, and the PX303 ever so slightly more bass. But I was also emphasising that it was possible to extended the dynamic range lower on the same model with higher value DC blocking capacitors too for certain models such as the JX505.

I understand the unit was non-functioning, but I would have taken a risk as with all AIWA I buy. €40 (+ postage) is a reasonable price for an "untested" JX505 with some accessories. Although I personally would not have paid much more.

I actually got my second JX505 in an untested condition. Ok I probably paid about €30 including postage, but it was not including any accessories. When I received it, it was working but had numerous issues (leaked capacitors, crackly volume control, no FM radio). I have fixed all these problems and it is a bargain at that price I paid.

I have paid more for what have been claimed to be fully working AIWA merely because other people bid the price up believing them to be. However I want the item not because it is fully working, but because I know how rare the model is and how seldom these turn up for sale. It is safe to assume that some amount of work will be required on these AIWA despite whatever claims a seller makes about it.

Untested ! You got it ! Untested... Tell me who in this world don't have a pair of AAA batteries at home ?

Although I have not bought any Aiwas online, when I find them locally I just accept that it will have cap problems no matter the model and the unit will not work anyway.

If it is claimed as fully working, is quite unlikely as the capacitor work required to restore an aiwa is not simple, and the seller would mention that then.

Only about once or twice I got a surprising machine that worked the way it is supposed to. (Most Sony machines on the other hand, mostly just need a new belt and are good to go)

Truthfully they should have put a couple of AAA batteries in and checked it out. It would have at least proved power was available to the unit and probably added more to the final value. Just pure and simple laziness.

But have a look at this other JX505 which recently ended and was in a tested state of not working . Came with the same amount accessories.

http://www.ebay.co.uk/itm/AIWA...;hash=item27be0f0bfe

Ended even higher when it was clearly stated that it was not working.

I was following this one too , that's why i didn't hesitate to place a 89 euro bid on a working unit in even better cosmetic condition ,hopefully(?) the seller was shipping to Germany only and i got allowed.

When you got the required accessory to test a walman(with radio!) and you claim "untested" wether you're lazy or... good luck!

Back to the 707 , let me know ,the second solenoid seems to be different than the upper double one is that it ? No particular care to this one ? About the double one , should i heat both pins and carefully lift at the same time ? Last time i tried braid (not raisin impregnated) with my 849 it didn't worked very well , i'm best at heat and lift ,i will yet buy some raisin impregnated. About the 707 , it's only a matter of belt and caps ? I'm asking because 849 is not only a matter of belt and caps ,there's further servicing.I have opened my second unit , changed the belt , it worked (reverse pb) for a few time then the problem occured again... Yet i've won a more accurate recording speed with lesser wow and flutter if not anymore(need further analysis). I also find it now more powerfull with a better "shlack shlack" mechanics sounding. This one still had a lot of fresh grease unlike my other 849. I've found a strange belt inside ,larger than my other 849 ,and according to my newly bought 849 , the screws were like randomly mounted ,had it been serviced ? I couldn't tell... the soldering points semt genuine or it was properly done , i don't know.It came from Thailand. There was a little rust inside but not to important ,but not as good looking as mine that spend his life in France.Caps seems there were original. I think i will sooner or later try to get new pinch rollers to see if it could be the issue with those. Could you please also tell me what belt to order ? Seeing both mechanics i don't think they share the same...

The record mechanism solenoid does not require as much care as the delicate playback solenoid, BUT you still need to be careful not to apply too much heat otherwise the copper trace can lift from the PCB underneath.

Since I know how much you hate removing flexible flat cable, it is possible to carefully desolder the record solenoid without removing the flexible flat cable, to do so you need to carefully arrange the flexible flat cable in such a way to allow you to desolder under it. I do not recommend desoldering over it through the hole, as you run the risk of melting the flexible flat cable. Note that if you are not careful, it is extremely easy to tear or split the flexible flat cable in this model. If that should happen, then there is a strong chance the JX707 is un-repairable.

I use these belts

http://www.turntableneedles.co...l-82-Inch_p_484.html

You may want to check that the door is aligned correctly and that the hinge screws are on tight before closing the JX707 after replacing the belt and caps, there is no other way of getting to them otherwise.

You may also wish to consider changing the memory battery, but that is hidden inside the door. Here is the link to my thread on that.

index.php?board_oid=193392314111653483&content_oid=224074607856455368

If you get unstable playback even after cleaning the pinch roller and capstan, then check that the tape guide posts on the pinch roller housing have not been damaged or broken off. If they are, then you will need new pinch roller housing. Not fixing this damage will cause any cassette tape you play to get one edge chewed or the tape itself even eaten.

Thanks for advices ! I didn't remember there was also that flex cable matter... This unit is so lovely i wouldn't like to ruin it... All the tape guides in my walkmans are ok. None of them eat the tapes.If there's no better choice i will consider desoldering the flex cable of course.Hoppefully it doesn't seems to be the same unsolvable issue than the 849.Each time i solve something , something else occurs... The rew issue was solved with contact spray on the switch to the edge(no need to open!)  BUT don't use it with the center switch since it don't like it , i'll have to clean the board again...

edit: ok i see , the record solenoid is under the large flex cable wich i suppose is attached to the door ,i think i can manage to work without desoldering it,at least i hope...

A few words quickly about my just received western JX707 , i'm surprised the belt seems fine and the clock battery is still alive. The radio side is working perfect (plus beep-beep-beep and girl's voice) ,very loud. The proble is on the tape side , i hear a lot of crackling , sound coming suddenly louder(looks like it loads...) ,of course caps. I didn't know the were a specific amplification circuitry for radio and tape ? With my JX303 , caps issues would concern both.

Yes, it is quite rare that you have a JX707 with still it's original belt. I have only seen 2 that still had good belts out of eight. All the rest either had stretched out belts or were a gooey mess.

To answer your question, the radio and tape inputs are separate with the record/pre-amp TA8155FN IC chip. The radio comes into the chip on pins 13 and 14 and the tape inputs on pins 4 and 5.

If you are getting crackle on the tape side, then there are three possible scenarios which may be your cause. For once, I don't think it is bad caps. Check that the flexible flat cable connecting to the playback/record head is intact and free from creases or tears. Also check that there are no dry joints where it connects to the PCB. Finally, there are two switches inconveniently located underneath the pre-amp IC chip that select the direction to the pre-amp. These may need cleaning with some switch cleaner.

Thank you ! Now that you tell me an remembering some troubles with one of my JX849 ,it could well be a switch. The unit looks like it was barely used so i don't think it may be the flat cable but only an inside check will tell.

edit: i was wondering about caps leakage , do you think they leak when unit is in use ? I mean would they leak while using it ? Do you think that chemical in the caps become dangerous because you don't use it ? Now as you told me i store them upside down (of course not all of them depending the motherboard position).I don't know if you remember my JX303 board , it was stored vertically if i remember well and horizontally too side up , for long periods of time ,you know the result.

They may leak if the rubber seal has shrunk usually due to age. They may also leak if the electrolyte over heats and the pressure build up causes them to leak too.

The aluminium plate inside will dissolve into the electrolyte and the plates will thin out over time if the electrolytic capacitor is not used, but we are talking a very long time say several years. The aluminium can be made to redeposit back onto the plates if the capacitors are gradually worked up again to normal operating voltage. This of course assumes that there has been no electrolyte loss.

I store most of my AIWA door side down to lessen the chance of leaked electrolyte migration.

That's what i do now ,very good advice. Some musn't be stored that way like the PX747-337-347 and the likes am i right ?

Would you please check your volume potentiometer ? The zero position is silent on my western 707 , i have sound on my asian one ,strange.

I tried 3 examples.

The JX929 was loudest, but one of the two JX707 were a lot quieter than the other JX707. When I say the JX929 was loudest, it wasn't that loud - barely audible. I was still able to make out the sound from the quietest JX707. I guess this is just down to tolerances on the volume potentiometer.