Servicing a SONY DAT machine (Pictorial)

[vallentin]

Yes, I have everything cleaned and relubed with lithium grease. The silver hook slides freely considering that quite powerful spring.
There was a huge blob of epoxy or CA glue in the red encircled area, removed it, but nothing changed.
The best I got in FF or RW was 0.5mm distance from the capstan without a tape inside and the pinch roller no longer engaged during operation.
With the tape, there was no playbck, FF or RW. I'm thinking brakes were not released in that position with a tape inside. I tried different positions with the encoder but the results are the same.
Defective encoder? But how? Its tracks are not cracked or worn beyond recognition. Measured with multimeter they all pass.
I still can't figure out which plunger is responsible for the pinch roller release during fast forward or rewind.
The voltages for the plunger circuit are within spec but voltages only don't say the full story. Maybe I have a weak component in there.
I'll have to remove and check them one by one.
I plan a full recap on the unit, maybe the problem is electronic and not mechanical and I have not yet changed the mandatory 6800uf from the PSU.
ESR wise is ok, and has not yet leaked its chemicals.
The PSU seems to have been recapped at on point, but I don't trust those no name AFG caps.

 

[hdrobien]

Beside the one used for the brakes, the other plunger of the 55ES "locks" the mode motor. It has no direct effect on the pinchroller release.

The "mandatory" 6800 µF capacitor on the PSU concerns the 59ES which is completely different. No known issue on the 55ES PSU.

Have you checked S902 on the side of the transport ?

 

[vallentin]

Yes, I treated the S902 with deoxit and it works. Maybe there is an issue with its travel/activation distance. I have a couple of spares and I will change it entirely. Or buy a new one. I'll report back on this subject.
The PSU was recapped. Don't know when. But all the caps are chinese Aliexpress junk. I found a single Elna in there.
Thank you for your help!

 

[Dimitris_]

Hi friends!

New acquisition here: I recently get a nice looking DTC-75ES.

Its the same as 55ES but this is the US version with 120AC input.


While i was cleaning the mechanism, i notice that S1 and T1 guides are loose (the brass part from the aluminum base) and the 2x small pins that holds the tape with an angle are also loose.

It is easy to remove both guides with my fingers...

The question is, what type of glue i can use to put it back? and regarding of the small pins how to properly set their height?

I also have a 55ES. It's a common fault on this? should i check my other unit as well?

Thanks!

 

[hdrobien]

Hi

The pins and guides problem is very common among all models using this transport (from the 1000ES till the ZA5ES).

I usually use a small plier to make very light grooves on the brass part of the guides and then force them back in.

It may slightly alter the height of the guides, so may need tracking adjustment.

For the pins, just force them till the bottom (no need for height concern).

 

[Dimitris_]

Hi

The pins and guides problem is very common among all models using this transport (from the 1000ES till the ZA5ES).

I usually use a small plier to make very light grooves on the brass part of the guides and then force them back in.

It may slightly alter the height of the guides, so may need tracking adjustment.

For the pins, just force them till the bottom (no need for height concern).

Hi hdrobien, Nice to see you again!

I was hopping for some kind of glue to be honest.
Your solution should be fine, but because i don't have your experience i worry that i will do some damage to the guides, then it's game over for the deck...

(the only parts that are still available / clones are the encoder gear and the pinch roller).


Re the pins i did try to force them inside but compared with my 55ES, especially the right one from T1 guide, i think get lower than it should.
So i take it out again, put a test tape and thread it manual to the head. Then i adjust the height of the pin so it will touch the whole surface of the tape and then apply a tiny drop of superglue from the underside of the pin.

Later i will check my other units as well. Maybe my 55ES that i use as a reference is also loose and make me think that the pin is lower than it should...

 

[hdrobien]

Of course you can use glue, but I prefer to minimize liquids (glue, oil...) in a DAT transport, especially near a tape guide (you can spoil the screw that secure the guide height with glue or the guide screw itself).

I am surprised that the pins may go lower than intended.

 

[Dimitris_]

Good day!

Tried yesterday with superglue. Unfortunately the glue doesn't really stick with brass and aluminum... Need to find something else.

And of course the deck need alignment, and i don't have a trusty tape...

Re the pins height, do you think are ok? I think S1 need to go a little further inside...

 

[hdrobien]

Hi

I don'k think that there is a problem if the pins are a little bit too high. The opposite would be problematic.

 

[Dimitris_]

Thanks hdrobien, This is also what i thought!

By the way do you (or anyone else) have the original test tapes thus a perfect calibrated deck?

i wondering if someone can make for me a tape from a perfect calibrated deck in order to use it as a reference to calibrate mine.

 

[hdrobien]

Yes, I have the test tapes.

 

[Dimitris_]

Wow! nice collection there!

Can you make for me a tape from your trusty deck?

I can send you an empty tape from Greece or you send me one of yours and send you the money via paypal.

Thanks.

 

[hdrobien]

Ok.

I should have some brand new 15mn or 35mn Sony that would suits well.

 

[Dimitris_]

Perfect! 35min i think is ok!

Please send me the total cost via pm (tape + shipping to Greece+ your work) and your paypal address in order to send you the money!

Really appreciate your help! Thanks

 

[hdrobien]

Ok, I will try to record a 1 kHz signal from a digital source.

 

[Dimitris_]

Thanks a lot!
Take your time, we are not in rush. It's just a hobby after all!

 

[alfista]

Thanks @hdrobien, deck 1 (the older 59ES) plays fine, but from time to time it starts playing digital noise every +/- 10 seconds, but after it warms up. My issue with caps is with 1000uf ones, on the board they are 63V, but on the service manual they are listed as 50V. I think I'll need other caps if I decide to replace them. What do you think, should I replace all the caps on the power board? Currently only the 6800uf is new.

Deck 2, the newer one, is the one that doesn't play now (it was working last week). It retracts the arms and the drum rotates. When it was working, it showed a similar behaviour as deck 1.

Hi @hdrobien I fixed my first 59ES. That digital noise every 10 seconds or something like that, was because part of the drum was magnetized, or at least that was the problem I think. How I fixed that? By chance I touched the wires that go from the drum to the board with the screwdriver I used to adjust the arms. This screwdriver is magnetic so after touching one wire, that noise instantly disappeared.

And I had luck, as my Aiwa XD-S260.I was using as reference was properly aligned I think. My TCD-D7, and both 60ES I bought as non working, after cleaning and recapping the amp, play my reference tapes without problems and if I record something on them, the Aiwa plays those tapes fine.

 

[Dimitris_]

Yes, I have everything cleaned and relubed with lithium grease. The silver hook slides freely considering that quite powerful spring.
There was a huge blob of epoxy or CA glue in the red encircled area, removed it, but nothing changed.
The best I got in FF or RW was 0.5mm distance from the capstan without a tape inside and the pinch roller no longer engaged during operation.
With the tape, there was no playbck, FF or RW. I'm thinking brakes were not released in that position with a tape inside. I tried different positions with the encoder but the results are the same.
Defective encoder? But how? Its tracks are not cracked or worn beyond recognition. Measured with multimeter they all pass.
I still can't figure out which plunger is responsible for the pinch roller release during fast forward or rewind.
The voltages for the plunger circuit are within spec but voltages only don't say the full story. Maybe I have a weak component in there.
I'll have to remove and check them one by one.
I plan a full recap on the unit, maybe the problem is electronic and not mechanical and I have not yet changed the mandatory 6800uf from the PSU.
ESR wise is ok, and has not yet leaked its chemicals.
The PSU seems to have been recapped at on point, but I don't trust those no name AFG caps.

Hi

I just notice from your video that you showing that the big black gear is moving freely on it's guides, but did you check if the silver hook can move against the black gear?

I think there is your problem. The old grease stick the hook with the gear. I use a bottle of degreaser spray to clean mine and then need to re-align the rotary encoder to make it work.

 

[hdrobien]

It was also my best guess, but vallentin said that it was moving freely : The silver hook slides freely considering that quite powerful spring.

 

[Dimitris_]

I know but he didn't touch it in his video, that's why i mention it.

Maybe he thought that the spring keeps back the whole gear??

Can't be anything else. This or the rotary encoder is misaligned or dirty.