Aiwa XK-S9000 Rebuild and XK-009

[braxus]

I sent my Aiwa 9000 deck to the Sony service outlet in March. It was to get new belts and the head realigned. I asked if head wear or capstans are worn enough to replace them. I looked inside and with all the PC boards this thing has, I'd was afraid if they ever had to replace numerous caps in this thing. The total cost of buying this deck pre-repairs was around $1800. The last deck that sold on Ebay, sold for $294 in good condition. Kicking myself for not waiting since I could have bought practically new decks for way less not long ago. I expected the repairs to cost around $200. Being the heads in this thing are amorphous, they didn't wear much. I bought a previous XK-009 deck which the owner told me had caps replaced in the power section. When I got it all it needed was new belts. I also got another 009 deck, since I sold the last one (my mistake).

They did an estimate on the deck doing a pre-check on it. The job as it was to replace all 4 belts on the Aiwa 9000, plus realign the heads. They tested the deck to find out if the heads are worn or not. The tech said its unlikely the heads will ever need replacing, since they use glass type heads (aka amorphous heads) in these decks. He did say the 9000 was very well built, as not one cap needed replacing since this deck used very good caps in it (unlike todays stuff he said).

They finished the repair of the deck a week ago and I just picked it up. While there I dropped off a second Aiwa deck- the XK-009 I have which will also get new belts and checked over.

Notes I got back from the tech were this:

He was VERY impressed of the frequency response of the deck at 0db. He said not many decks do what this one does. He aligned the heads and the belts were replaced. But checking it over he also noticed this:

The calibration controls have drifted over time and are no longer accurate. There is no adjustment to fix this. So basically the frequency response will be out if I used the deck as is.

Also the right meter is 2db down from the left meter. Again no way to correct this.

Speed was adjusted. Left right record balance was adjusted. Since the calibration was off, they internally set the deck for XL-II tape and DR-I tape.

Again all caps were good and parts for the major stuff was still available for this deck.

So darn it. I am so used to setting bias by the meters, that I won't be happy to have to go back to the old method of doing it by ear. Its not making me want to move this deck to main duty if I have to guess again on adjustments. More the so reason to buy a Tandberg 3014.

[Nak_novice]

Braxus, Your level meter mismatch is something I have had in the past on one of My ZXL's and it drove me to distraction so it had to be resolved. It turned out that although some of the capacitors had not failed, they had drifted in value over the years. Also, the tolerances used were not particularly tight at +/- 5 %. With a bit of drift, a pair of 680 pF caps at the opposite end of their tolerances could therefore be 620 and 740 pF causing a variance in each channel. It depends how much it annoys you I suppose.
For my ZXL cap replacement projects, I sourced good quality F (1%) tolerance capacitors (53 per deck). I even had to have one made to order for the EQ circuit (620pF) as it was not available anymore. Anyway, levels are now sorted and it was worth the effort and the sense of achievement for me was most rewarding.

[braxus]

Would the caps be why the bias calibration would drift over the years and go away from factory specs, and not be able to be fixed?

I would never tackle a job that requires soldering in such a deck, so it would have to go back to the tech. Would they know which caps to replace to do the bias calibration in spec?

[Nak_novice]

I suspect that the caps may well be the reason. There are resistors, transistors and caps in the bias oscillator which if you want could all be replaced to get the calibration within spec although Its probably no more than 6 caps that may be affecting it, 2 or 3 in each channel. The caps will probably have their values printed on them but if not, the PCB or schematic should reveal the parts required. I don't accept that there is nothing that could be done.

The ZXL for example has 404 capacitors spread over 7 of it's 23 PCB's. of these caps, only 53 were the dodgy orange polypropylene variety that Nak used but of these only 12 were in the bias oscillator area. Others were in the record and playback amps, the meter circuits etc.

Two decks that I have rebuilt would only play on 1 channel, would not record, wouldn't calibrate at all, but were fine after just caps were replaced and the bias trimmers set up.

There may be a trimmer that could be adjusted internally to set up the bias, like on many Naks. (Sorry, only familiar with Classic Nak decks).

Perhaps the level meters need calibrating separately from the bias oscillator?

All 5 of my 1000 ZXL's have had their Polypropylene Cap problems and I suspect that most decks of this era would benefit from a replacement programme.

Caps typically cost between $0.10 and $2.00 each so its not unreasonable to tackle 1 pcb at a time. If you ever need to identify a replacement capacitor, you can let me know the details on the original and I will probably be able to let you know where to get a replacement and which part is an exact substitute. Material, voltage rating, tolerance, farad value and physical size are the 5 critical factors.

Is the service centre reputable?

[braxus]

The service center is good as they tested things I wouldn't have considered. But they may not have wanted to do it because of the time involved. I'll ask them about it and see what they say. I do not want to touch this deck myself. I've spent too much on it to make any mistakes on repairing it myself. At this point the deck cost me $2000 with all the costs involved in getting it and repairing it.

[Nak_novice]

Good call Braxus, See what they say. Ask the old guy with the overalls on rather than the new young techs!

[braxus]

Yah I've got to deal with this issue. Its a major one for me since I plan on using the deck for recording and I hate setting something by ear.

[braxus]

Geesh. I did a test recording on the Aiwa and checked it in my Sony to make sure. The level is down on the left side when recording and its confirmed when playing on the Sony. The meters on both decks told me the left was down too, so the meters are accurate. Also the Dolby S circuits are losing high end slightly when compared to using Dolby B and C and Off. I had to adjust the bias to bring the high end back. I don't know what the tech is talking about because when using anything but Dolby S, the bias sounds fine when using calibration to set it.

I really hate to take this thing back in because it sounds like many of the caps in this deck have degraded and I know it will be VERY expensive to replace them all. I thought it would be better just to sell the deck, but I've invested way to much into it to ever recoupe 1/3rd of what I put into it with the known issues. I wish I got that new deck that was available at the beginning of the year. I would have paid less too. Would I be looking at $700 to recap this deck by a tech? All I know is there is a huge circuit board dedicated strictly to Dolby S, so it will get expensive.

[Nak_novice]

Braxus, starting from cold, It would take quite a few hours to do the work. But the actual job of desoldering the parts and fitting the new parts in relatively quick and easy.

The hard part is identifying the caps that need replacing and their specification, finding out where to get the replacements (Usually a few different suppliers) and getting them all to hand. This really does take hours but depending on the availability and quality of info in a service manual, it could be done beforehand and the parts supplied to the tech to fit.

Following the fitting stage, there may well be various electrical calibration stages to settle everything down, but not too extensive. To give you an idea, I can recap a Nak 1000ZXL's 53 polypropylene caps in 3 hours or the 21 in a 680ZX in about an hour, but only because I have done it many times and have all the parts in stock and the service manuals to hand. So the hard part isn't the fitting stage but the preparation.

The good news is that the preparation can be done by you or someone with some knowledge of the decks internal componenets if you have a service manual. Definitely a worthwhile investment, do you have one?

[braxus]

Yes I have a service manual, but understanding it is another thing. I don't have a clue how to read diagrams. I did however give the tech a manual. When specifying parts to order, can you request tight tollerance high quality caps? Or will the tech place give you whatever they feel like? Any suggestions there?

I could email you the service manual if you wanted to understand what I'd be up against. Only problem is the file is 13 mbs long.

[Nak_novice]

Hi Braxus,

By all means, send the manual, I will see how the job looks and try to offer some assistance. (Benstratford@aol.com) Usually, the tech would supply a basic part if he has a choice, but closer tolerance parts are available.

For one ZXL deck I managed to source 49 of the 53 caps in 1% polystyrene rather than 2 or 5 % Polypropylene. A higher voltage rating was also selected. The downside of this is the higher cost of course! The other 4 parts were not then available in polystyrene at a suitable size. The finished deck sounds so good and should stay healthy for ages - Fingers Crossed!

In high end gear, not only do they have tighter tolerances but they are matched in the L + R channels by measuring the parts and fitting the same spec components with no definable difference in values between them. This can be done with cheaper parts just to ensure that either end of the tolerance spectrum are avoided. The biggest issue with replacement caps is the minimum order quantity which is a real pain if its 500 or 5000, but most are available in packs of 10 or individually if you look hard enough.

Another issue is previous repairs that may only have used a cap that is near enough right, which must be identified to avoid replacing a wrong one with the same new wrong one.

[braxus]

I tried sending the file, but the two email sites I used have a 10mb limit. The file is 13. Not sure what to do really. I can't break the file down. I guess I could try and scan it, but that will be tomorrow if so.

[Nak_novice]

As I am not familiar with the Brand, I downloaded a SM for the XK-009 and the good news is that the manual is pretty good and there are not too many PP caps and that they are on the whole readily available. One or two may be tricky to find in small quantities though. (E.G. 560pF)

Anyway, If you can perhaps upload the manual to somewhere like www.EBAMAN.com, I can then download it and have a look. Not sure if it would fit on a cd or how to do that.

Off to UK tomorrow so it may be a while before I can get back to you, but if I can download it prior to leaving, It would make the flights less boring!

[braxus]

I tried to download the file to the site you suggested. But I realized that it would be in the public domain and the file I have is copyrighted and is not to be distributed. So I cancelled the download. I'll have to scan up the pages of parts sometime in the next couple days. But I decided to at least try and get the record level even, so I went to the manual and looked up the pots. I took the deck out and removed the cover. The Dolby S board is in the way, so I had to remove it. I then found the pots and did some recording. Now this time for some reason the input level is low on the left side on monitor. I don't know whats up with this deck. I adjusted the right channel down a little to be more even, but with the input out- its not going to work. There is no adjustment for input volume levels to even it out. So I put it all back together and will do more testing to figure out what course of action to take next.

I took 3 shots to show the 2 main boards in this thing. You can see how many caps it has here.

[braxus]

I got my quote back for the XK-009 repair and it only cost $115 to put in 3 belts and align the heads. This deck seemed to be in better shape then the 9000. Not sure what to do about the 9000, as it looks like Im going to have to send it in again.