Servicing a SONY DAT machine (Pictorial)
- Thread starter SaSi
- Start date
dr*audio
Fish fingers and custard!
Craft Stores and fabric stores sell the thin stuff. It is difficult to find the really dense material, though. Some of the thin stuff just falls apart when you cut it into small pieces. You will have to experiment. If you can find anyone who makes hats, they should have the denser felt. May be some of that in Europe, but not in the USA.
Tinman
Super Member
I'll try that when I set up the big tank. It cleans microscopically clean, so it should be fantastic on records.
SaSi
Seriously Illogical
OK, we are getting way-off topic here, but I was also thinking:
A square plastic container,
a heater,
a rotation mechanism mounted in the bottom of the container,
a KEF T27 mounted flush in the bottom in a small opening facing upwards,
a record rotated in the water
The tweeter has a plastic dome so it should be waterproof. And it can produce sounds in excess of 30kHz. And should be able to take 35~40 degrees (Celcious).
When you try that ultrasonic cleaner on vinyl, I guess it should be a good idea to start a relevant thread in the TT section.
Anyway, to get back to the relevant topic:
The original DTC59ES that was under surgery in the beginning of this thread is reassembled and undergoing a burnin test since last night. (repeating a 120meter tape with 10 tracks at no end. This tests play (and the tension pads I improvised) as well as rewind. And as the tape is twice as long as it supposedly should be handled by the deck, I will be happy if it passes the test for 24 hours.
When I get home, I will check and hopefully then post pictures of the cleaned and relined tension pads as well as describe the forward and back tension calibration + tape/head alignment over the weekend.
A square plastic container,
a heater,
a rotation mechanism mounted in the bottom of the container,
a KEF T27 mounted flush in the bottom in a small opening facing upwards,
a record rotated in the water
The tweeter has a plastic dome so it should be waterproof. And it can produce sounds in excess of 30kHz. And should be able to take 35~40 degrees (Celcious).
When you try that ultrasonic cleaner on vinyl, I guess it should be a good idea to start a relevant thread in the TT section.
Anyway, to get back to the relevant topic:
The original DTC59ES that was under surgery in the beginning of this thread is reassembled and undergoing a burnin test since last night. (repeating a 120meter tape with 10 tracks at no end. This tests play (and the tension pads I improvised) as well as rewind. And as the tape is twice as long as it supposedly should be handled by the deck, I will be happy if it passes the test for 24 hours.
When I get home, I will check and hopefully then post pictures of the cleaned and relined tension pads as well as describe the forward and back tension calibration + tape/head alignment over the weekend.
SaSi
Seriously Illogical
Update
Well, the unit passed the test - almost.
Playback and FF/REW works great. No more curling the tape off the pinch roller (as back tension is there) and FF/REW is fast and stable.
But, one out of four times, ejecting the tape failed. The transport tries to retract the tape into the cassette but something is sensed wrong and the tape is extracted again. The cycle goes on 3 times and then the transport stops. It is required to shutoff the unit and upon power-up, eject succeeds.
Something to look into and a great excuse to strip down the transport once more and take detailed shots for your benefit.
Well, the unit passed the test - almost.
Playback and FF/REW works great. No more curling the tape off the pinch roller (as back tension is there) and FF/REW is fast and stable.
But, one out of four times, ejecting the tape failed. The transport tries to retract the tape into the cassette but something is sensed wrong and the tape is extracted again. The cycle goes on 3 times and then the transport stops. It is required to shutoff the unit and upon power-up, eject succeeds.
Something to look into and a great excuse to strip down the transport once more and take detailed shots for your benefit.
SaSi
Seriously Illogical
I am not exactly sure what you mean by "mode switch". Apart from the cassette sense pin switches, the unit has two switches sensing the location of the slider controlling the tension arms and pinch roller. First switch senses "arms extended" and the second switch senses "pinch roller engaged", or so I gather from the state of the transport when the switches close.
Now, if this is what youi mean with "mode switch", you could be right, as I recall one of those switches to be rather abused and sticky - perhaps from too much grease.
In any case, a total stripdown is called for.
dr*audio
Fish fingers and custard!
Oh, THAT transport. I've worked on those. Those friggin' switches went bad after only a year or two. I'd check them out for sure. The mode switch I was talking about is a rotary switch about 20mm across with maybe 5 or 6 wires going to it, or a flat flexible cable. A friend of mine has a Sony that has one. I thought it was a DTC-690 but I'm not sure. Or maybe DTC-A7? If memory serves, the mode switch is located near the pinchroller, or to the right of the head. Those go bad all the time. VCRs had them, too.
SaSi
Seriously Illogical
Replaced the sensor board with one from the donor machine. It works like a charm now. 20 out of 20 cycles of load, play, ff, rew, play, stop, eject worked perfect. Thanks for the hint.:thmbsp:
Took some pictures of the process as well. I have now the transport in a state ready for alignment.
More to happen tomorrow.
Took some pictures of the process as well. I have now the transport in a state ready for alignment.
More to happen tomorrow.
dr*audio
Fish fingers and custard!
The little microswitches used in the DTC-1000ES to sense the tape and record interlock are dodgy too, but I've been able to resuscitate them with cleaner and De-Oxit. Took a few treatments but they have been ok for over 2 years now. Digikey sells some microswitches and eventually I'll check them out as a replacement. Glad I could help. Sony has a bad habit of making the same mistakes over and over again. Grease that gets gummed up, tape guides in DAT decks that come loose and lose the height adjustment, using mounting screws on pc boards to complete ground paths on the board (screws get loose and you all of a sudden get poor ground paths, noise and dc offsets between 2 places in the circuit that are supposed to be ground.)
Sony mechanism trouble...
Hi,
After reading a major portion of this interesting thread I wanted to see if my Sony DTC690 would still work after it had been doing nothing for at least 3 years. It seems these Sony mechanisms are rubbish: last time I used it nothing was wrong with it and now, because it probably has been sitting too long doing nothing, it won't even load a tape anymore. The problem lies with the right spool, which for some reason won't turn around anymore when a tape is loaded. Because of this there is no tape tension, and therefore the loading fails.
Since I bought this deck that it has been sitting there more for looks then for purpose, only 25 tapes have been recorded on it: mostly 60 and 90 minute tapes, along with about three 120 minute tapes and one 180 minute tape. The whole unit it in mint condition, I even have the original packaging and because it probably now has been sitting too long doing nothing I can take it to a repair shop, which s*cks as repairs on DAT decks always cost $$$$$. Anyway, anyone who has ideas what the problem could be, as this unit has barely been used wear & tear would be a ridiculous reason.
A friend of mine also has had no luck with Sony DAT decks. His DTC690 ended up on the junk yard years ago, but at least he taped about 150 tapes with it. After that he got a DTC57ES, which again after 3 months began to show the same mechanical problems he had with his DTC690. So his 57ES also ended up in the trash. He now has a DTC60ES, which so far seems to be working reasonable... but he already has detected the first minor signs of the very same problems that surfaced with his prior two Sony DAT decks. If the 60ES fails he's never gonna buy a Sony DAT machine again :thumbsdn:, but get a model from Tascam instead.
Now that my DTC690 also has problems it appears to me that whatever you do with these Sony DAT decks you always loose: if you use them regularly they are prone to failure... if use them scarcely or put them back in their original packaging for years they'll also stop working.
Anyway am I looking at a reasonable repair or am I better of trashing my DTC690 after recording the a 'massive' amount of 25 tapes...
Hi,
After reading a major portion of this interesting thread I wanted to see if my Sony DTC690 would still work after it had been doing nothing for at least 3 years. It seems these Sony mechanisms are rubbish: last time I used it nothing was wrong with it and now, because it probably has been sitting too long doing nothing, it won't even load a tape anymore. The problem lies with the right spool, which for some reason won't turn around anymore when a tape is loaded. Because of this there is no tape tension, and therefore the loading fails.
Since I bought this deck that it has been sitting there more for looks then for purpose, only 25 tapes have been recorded on it: mostly 60 and 90 minute tapes, along with about three 120 minute tapes and one 180 minute tape. The whole unit it in mint condition, I even have the original packaging and because it probably now has been sitting too long doing nothing I can take it to a repair shop, which s*cks as repairs on DAT decks always cost $$$$$. Anyway, anyone who has ideas what the problem could be, as this unit has barely been used wear & tear would be a ridiculous reason.
A friend of mine also has had no luck with Sony DAT decks. His DTC690 ended up on the junk yard years ago, but at least he taped about 150 tapes with it. After that he got a DTC57ES, which again after 3 months began to show the same mechanical problems he had with his DTC690. So his 57ES also ended up in the trash. He now has a DTC60ES, which so far seems to be working reasonable... but he already has detected the first minor signs of the very same problems that surfaced with his prior two Sony DAT decks. If the 60ES fails he's never gonna buy a Sony DAT machine again :thumbsdn:, but get a model from Tascam instead.
Now that my DTC690 also has problems it appears to me that whatever you do with these Sony DAT decks you always loose: if you use them regularly they are prone to failure... if use them scarcely or put them back in their original packaging for years they'll also stop working.
Anyway am I looking at a reasonable repair or am I better of trashing my DTC690 after recording the a 'massive' amount of 25 tapes...
vincei
aka MasterControlMedia
Nitro70, I have had bad luck with Sony transports on certain decks. However, Sony's 4 head 4 motor decks are excellent, no comparison. Super quick, smooth, silent, all around superior. Of course this is my experience. I've had a DTC-59ES (failed), DTC-A7 (failed), DTC-87ES (ok 4H-4M), DTC-75ES (ok). I've also had a Technics SV-DA10, which was nice too.
SaSi
Seriously Illogical
I can feel you. One of the decks I've received was delivered full with instruction manual and a pack of cut pages from hifi magazines with reviews. Raving reviews. The unit is a 690.
Once you study the Sony mechanism against, say, a Panasonic or a Technics, several small details become apparent on how simple things are kept simple and other mechanisms appear to be less prone to faults.
What is really a mystery is checking how a sony computer dat mechanism is designed. ALL the problems related with the Sony transports AREN'T there. Separate direct driver motors for each spool, no belts or pulleys, just gears and metal gears where torgue appears critical and high.
Regarding your deck's problem, my first reaction is: Don't trash it. The problem is bound to be simple to fix. This whole thread is about such problems.
I would like first to make sure of what the symptom is. We are talking about the right hand side spool, right? The take up spool. You load the cassette and the left spool is unwound but when the deck wants to move the tape slightly forward and backward to make sure it has been tensioned OK over the drum, the take up spool doesn't turn. Is that the symptom?
First of all, you can remove the deck's cover to verify tape loading and motion. It's not simple to do that through the small cover window. Or you can remove the cassette compartment cover for a better view.
The simplest reason I've seen that happen is because the cassette is faulty. when it is inserted in place, the front flap is opened and the bottom drawer cover is pushed back. This causes two spikes inside to retract from the geared reels and allow tape movement. Some cassettes sometimes don't release the RHS spike and that locks the reel in place. Just try a different cassette first.
A second thing to try is to repeatedly (>10 times) load and remove the cassette. Eject the cassette as soon as it locks itself in place, before the deck finishes the tape loading process. Sometimes, the "elevator" doesn't properly pull the cassette into proper position and the aformentioned spike is not retracted because of this.
Or the tape loading path might have been affected. If for example the tape isn't threaded through the pinch roller and capstan, it isn't moved properly and it shows as the RHS spool not moving. It could be that the pinch roller is bad.
If the above fail, then it is the turn of the transport to be examined. A violent removal of a cassette in the past might have broken or bent one of the tape guides (S1 or T1) and the tape might not be properly loaded.
Or, if a cassette was left inside the deck for years, the tension pads were set to press against the spool plates and they may have gone bad. Their glue is known to bleed and cause the tension arms to stick against the reel plates.
If you could take a video of the tape loading process through the cassette opening or the top (with sound), it would readily help identify what the problem is.
The 690 isn't a bad deck. The mechanism is the "most refined" transport of the consumer series and survived intact for a decade or so.
I have repaired a few of those and use one myself day today and given the other two to friends who run them daily for background music playing a 120m tape at half speed for 8 hours without any problems.
It might be worth to give it a shot at repairing it yourself, depending of course on how confident you feel with all things mechanical.
Hi Sasi,
Thanks for all your help and suggestions.
Maybe I was a bit harsh, but as you can imagine I'm not happy to see that my DTC690, despite my discrete use, now also has mechanical problems. I used it discretely because I knew that a lot of Sony DAT machines were prone to such problems.
Although places that will still do repairs on DAT machines are hard to find these days, thank goodness I know one. To narrow things down somewhat. Prior to yesterday the DTC690 had been boxed during the last 3 years and was stored away in my bedroom.
I've never left any cassette in the deck for days on end without using it. Yesterday I also tried to load several cassettes, 60, 90 and 120 minutes - all to no avail, so I think faulty cassettes can be ruled out. It also does not matter if the cassette is completely wound back prior to loading it, I also tried to load one which is almost at its end with the same result. Since I bought this new, not one cassette has ever been violently inserted or removed from the deck.
Interesting thing detail is that the mechanism makes a soft squeeling noise whilst trying to tension the tape during the loading process. While observing the loading mechanism through the cassette door its 100% clear that the take up spool doesn't turn at all anymore.
Yes, I confirm that this is indeed the EXACT symptom! I wouldn't be surprised if the problem is belt or pulley related. Beats me why on earth these were used in home audio DAT decks, whilst as you wrote, they weren't used in computer DATs.
One other thing you must know about is that despite the loading problem the digital counter of the deck will display an 'ABS time' which shows the position of the tape.
Besides the Sony I also have a JVC XD-Z505 (Panasonic mechanism): are you saying that Technics + Panasonic are less prone to faults because things were kept simpler compared to Sony mechanisms?
Thanks!
Thanks for all your help and suggestions.
Maybe I was a bit harsh, but as you can imagine I'm not happy to see that my DTC690, despite my discrete use, now also has mechanical problems. I used it discretely because I knew that a lot of Sony DAT machines were prone to such problems.
Although places that will still do repairs on DAT machines are hard to find these days, thank goodness I know one. To narrow things down somewhat. Prior to yesterday the DTC690 had been boxed during the last 3 years and was stored away in my bedroom.
I've never left any cassette in the deck for days on end without using it. Yesterday I also tried to load several cassettes, 60, 90 and 120 minutes - all to no avail, so I think faulty cassettes can be ruled out. It also does not matter if the cassette is completely wound back prior to loading it, I also tried to load one which is almost at its end with the same result. Since I bought this new, not one cassette has ever been violently inserted or removed from the deck.
Interesting thing detail is that the mechanism makes a soft squeeling noise whilst trying to tension the tape during the loading process. While observing the loading mechanism through the cassette door its 100% clear that the take up spool doesn't turn at all anymore.
Yes, I confirm that this is indeed the EXACT symptom! I wouldn't be surprised if the problem is belt or pulley related. Beats me why on earth these were used in home audio DAT decks, whilst as you wrote, they weren't used in computer DATs.
One other thing you must know about is that despite the loading problem the digital counter of the deck will display an 'ABS time' which shows the position of the tape.
Besides the Sony I also have a JVC XD-Z505 (Panasonic mechanism): are you saying that Technics + Panasonic are less prone to faults because things were kept simpler compared to Sony mechanisms?
Thanks!
SaSi
Seriously Illogical
On Panasonic/Technics transports, there are simpler mechanisms and less plastic. Correction, no plastic on gears, pulleys and levers.
What you described appears to be a bleeding glue from the tension pad that has caused the pad to stick on the take up spool plate bringing it to a standstill. Do you live in a hot place?
It is good that the tape counter shows ABS and tape location. It means that the drum and alignment is fine.
What you described appears to be a bleeding glue from the tension pad that has caused the pad to stick on the take up spool plate bringing it to a standstill. Do you live in a hot place?
It is good that the tape counter shows ABS and tape location. It means that the drum and alignment is fine.
That's why my JVC XD-Z505 (with Panasonic transport) probably still works fine... I tested this deck moments ago and it still is alive & kickin' :tresbon:
As for my DTC690: the place where I live can get hot during summer time. Although I always protect and if necessary shield all my audio- and video gear from direct sunlight at times during the summer the temperature in my living room can rise to about 29-30 C, which is pretty hot.
If the problem is caused by the pad being stuck to the take up spool plate: am I looking at something seriously, and more importantly would it be worth getting it repaired? As said, this DTC690 is as close to being mint as its gets, with only 25 tapes ever recorded on it, and play back hours have also been very modest.
SaSi
Seriously Illogical
Sometimes things break just because they aren't used. I know it sounds funny, but my Aiwa AD-F880 cassette decks developed a slack on the main belt just because I didn't use it much for a few years. It was 5 years old. I replaced the belt and used it regularly since then - 2001. It's working fine until now.