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Servicing a SONY DAT machine (Pictorial)

ok well I've put that brake pad where it should be. underneath where the felt pad should of been it was very sticky.

anyway, I'd be suprised if this was the problem as it's the take-up reel I'm focusing on.
It's all back together now and I'm just running a dat cassette. no problems so far but it's only been on a minute.
 
ok guys, bad news update. looks like I spoke too soon, been using my DAT player alot recently and then it did that thing where the takeup reel stopped. but this time it didn't shut the whole machine down but just stop.

Then I was having trouble with transport in general. in one instance I even heard the sound of something going round but NEITHER of the reels where turning (I think) then I tried to take the god damn tape out and it struggled, in the end after many attempts it did come out but the tape was left hanging out and all mangled. this has made me very angry cause that's tape's got some of my own music on.

I'll open it up tomorow to see what has happened, but I NEED you guys to help me again.
 
also whilst I'm waiting for saturday to turn into sunday does anyone know of possible replacement motors just in case that is the problem? thanks. I need to know ASAP really because I get very little my-time with my fulltime job I work like 70 hours a week and I dont have time to be fixing things so I really do need you guys to be quick with me.
 
ok so i've killed a (luckly a spare) tape!!! :(

What i did was decided the spring for the brake was too strong (not the pad brakes, the ring brakes controlled by the BLACK soloide) anyway, didn't loosen it that much. put it all back together tried a test tape, at first it didn't play so I thought, it must be the stupid senser buttons, after powering off and on again it did transport and stuff until nothing, took the tape out and it had sliced it in half!!! brutal!!
I don't want to waste another tape what the hell is going on? I might just post this dat deck to you Sansi.
 
ok, it MIGHT be working again now. so far no stoppage of the takeup reel.

what it comes down to I reckon is 3 things.

Motor: deffiently not the motor (in my case)
Belt: belt seems fine, not too tight not too loose
Brakes: well here you got 2 problems the pad brakes and the ring brakes.
 
Tape Path Alignment

SaSi said:
The two arm pinions are secured in place by two small round clips. One should be black and the other white. At least that is what I've seen so far. But not on this deck.

There are a lot of such clips - on the undercarriage - and one problem with them is they tend to go and the part that is secured - especially the arms - gets further dislocated. If this happens and the owner of the deck continues to try to load and eject tapes it is very likely that the steel part of the arm will jam and bend. Have seen this - haven't seen anything break yet.
Click to expand...

Hello SaSi & everyone, excellent post might I add also.

I bought a DTC-690 next to nothing after seeing this post and after grabbing a copy of the service manual. It was a dead unit and wouldn't power on. After some tinkering I figured out that the solder joints for one of the power regulators had broken off. Re-soldered and viola, came back to life :), but when playing a tape the sound was all messed up.

After reading this thread carefully I realized the S1 guide wasn't extending fully. Unfortunately in the process of figuring this out I messed around with the S1/T1 guide post adjustments thinking that was the issue initially.

It turned out the clip for the S1 guide arm had cracked and fallen off as mentioned, found the cracked clip in the gear housing, glued it back on and again viola the tape plays/records fine now as it goes correctly around the head. :thmbsp:.

However I'm concerned as I messed around with the guide post adjustments, it's off alignment and if I ever want to play anything recorded on another player. So basically was wondering if there was an easier way to get the guide posts adjusted back correctly without using a oscilloscope and special test tape (neither of which I have)?

Any pointers greatly appreciated, many thanks! :)
 
Concerning the guide adjustment here is what I do:
1- Set the left guide at middle position
2- When playing a tape that is supposed to have been recorded on a correctly aligned deck, turn the right guide and memorize position where music appears and where music disappears.
3- Set the right guide in middle position between the 2 previously memorized positions
4- Repeat 2 and 3 with the left guide

Trick: you can check that the guides are "correctly" set when the sound stays stable in fast forward.

I'm also experiencing the method of adjustment using an oscilloscope. Not easy but way more accurate.

By the way I was able to get my hand on a torque test tape. It is a very usefull tool when you have to replace the felt pads.
 

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hdrobien said:
Concerning the guide adjustment here is what I do:
1- Set the left guide at middle position
2- When playing a tape that is supposed to have been recorded on a correctly aligned deck, turn the right guide and memorize position where music appears and where music disappears.
3- Set the right guide in middle position between the 2 previously memorized positions
4- Repeat 2 and 3 with the left guide

Trick: you can check that the guides are "correctly" set when the sound stays stable in fast forward.

I'm also experiencing the method of adjustment using an oscilloscope. Not easy but way more accurate.

By the way I was able to get my hand on a torque test tape. It is a very usefull tool when you have to replace the felt pads.
Click to expand...


Hi Hdrobien, thanks for your reply. Great, idea, didn't think of using a pre-recorded tape to get the deck back into alignment. Now I just have to find one as I have a grand total of two blank DAT tapes which I bought to test the unit out. I guess it would be cheaper than an oscilloscope however.

Just out of interest, I was looking at USB oscilloscopes on Ebay like this one here (Max sampling: 8kHz x 1/ (4kHz x 2), Measurable frequency: 0Hz-3kHz), would these be suitable for testing the DTC-690, vs spending $$ going with something like the Tektronix 465B?

I haven't used an oscilloscopes since my undergraduate days :), mostly stuck with a multimeter for most things. Good job getting your hands on a torque test tape btw.

Thanks
 
I have tried both usb (Picoscope 2204 bandwidth 5 MHz) and analogue "oldschool" (Hameg 203-5 bandwidth 20MHz) oscilloscopes for DAT fine setting.

IMHO Analog is better, because it is easier to "understand" the signal, or more precisely, the envelope of the signal which is the key to the setting.

But maybe it is only a matter of broader bandwidth.

Anyway a 3 kHz bandwidth is way too low to visualize the signal.

Below is what you can see when the setting is done: a kind of stable rectangle between 2 sets of burst.
 

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Need sony 75es dat machine rotery encoder? Anyone know where to get one?
also called a mode switch......http://www.partstore.com/Part/Sony/Sony/DTC75ES/Sony/Sony/146472432/New.aspx

Out of stock on the sony site/hard to get part........does anyone know of a used parts dealer? I tried ebay to....cant find it......thats all it needs to work.

This seems like a very commen prob with this machine/and if you can fix it your self and find the part/there not to bad.?

Would appreciate any info guys....

Thanks,
Ed
 
I think that you can use the rotary encoder of the latest PCM 7*** series, reference 1-464-724-12.

Works for me on a DTC-1000es.
 
Dear Sasi,
I have red most of your work about Sony dat,
I understand that cleaning is an important step
to get these machines working,mine is a 59 ES
I bought it in the 90's and I haven't used it much
I forgot about it for along time because it was acting
up: distroying tapes and refusing to open or load.
Folowing your guidance I did clean it a bit without
dismanteling the whole transport,it is somewhat better
now but it still does not open all the way,would you suggest
that I should take it apart completely to fix that problem?
Any tips would be helpfull as I could not find any technician
willing to tackle the job in my neck of the woods.
Thank you for giving me hope. F.
 
Hi

What do you mean by "it still does not open all the way".

You mean the cassette loading (door opens...) or the tape loading (arms extend..) around the head cylinder ?

Pictures would be appreciated.
 
stevenson

thank you for answering,
what I mean by it does not open
completely is that the door does not
open all the way,the carriage on the side
does not make contact with the tiny black
switch (open side) it closes ok and make
contact with the other tiny black switch
(close side).
The consequence is that I have to pull
the tape holder the extra 2mm if I do
not want the door to close back immediatly
once the tape is back in the play position
the deck works nominally so far,
I hope that I made it more understandable,
again thank you for answering, F.
 
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