Servicing a SONY DAT machine (Pictorial)

[Dimitris_]

Good day everyone!

Yesterday I spend some time to disassembly again the unit and check everything...

I didn't find something wrong mechanically.
Everything is moving freely and smooth.

I clean again everything and put it back but the stupid solenoid didn't release the brakes.
(I'm testing without tape in, by pussing the microswitch with my finger to fool the microcontroller that there is a tape inside)

Could be possible electrical fault? The solenoid is getting around 3.2vdc when tries to operate.

It's moving, but not enough to release the brakes.

Anyone has an idea or recommendation? I'm stuck at this point.

Thanks.

 

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[hdrobien]

Good day everyone!

Yesterday I spend some time to disassembly again the unit and check everything...

I didn't find something wrong mechanically.
Everything is moving freely and smooth.

I clean again everything and put it back but the stupid solenoid didn't release the brakes.
(I'm testing without tape in, by pussing the microswitch with my finger to fool the microcontroller that there is a tape inside)

Could be possible electrical fault? The solenoid is getting around 3.2vdc when tries to operate.

It's moving, but not enough to release the brakes.

Anyone has an idea or recommendation? I'm stuck at this point.

Thanks.

I would check the transistors that power the solenoid.

Such solenoids are power at 2 levels: first level "kicks" the solenoid with high power, then second level keeps the solenoid triggered with lower power.

Maybe the kicking level is out.

According to schematics, the solenoid is triggered by pins 109 ("trigger" signal) & 110 ("kicking" signal) of IC514

Check Q511 and Q514 that generate "kicking" level.

 

[Dimitris_]

I would check the transistors that power the solenoid.

Such solenoids are power at 2 levels: first level "kicks" the solenoid with high power, then second level keeps the solenoid triggered with lower power.

Maybe the kicking level is out.

According to schematics, the solenoid is triggered by pins 109 ("trigger" signal) & 110 ("kicking" signal) of IC514

Check Q511 and Q514 that generate "kicking" level.

Hi hdrobien,

I have to say you are a genius!

It was the transistor Q513.

It was not open or shorted, but weak. I spend a lot of hours to find it...

Now the brakes (item 517 & 531 from SM) are working properly.


There is one last problem with this unit to call it fixed.

It's struggles to FF & REW. I found that is the upper brakes (the T shape brakes, item 425 from SM) that holding the reels.

The only way to fix it is by moving the pinch roller out of specs, closer to capstan by adjusting the rotary encoder.
(it's the pinch roller lever that is releasing the brakes)

SM is little confusing.
Its says it that the correct position for the rotary encoder is where the pinch roller touches the capstan housing in STOP mode.
The pinch roller will never touch the capstan housing. Will only touch the capstan in PLAY mode.



I found that other people have the same problem but i didn't found a solution yet.

 

[LUX-X2]

Hi hdrobien,

I have to say you are a genius!

It was the transistor Q513.

It was not open or shorted, but weak. I spend a lot of hours to find it...

Now the brakes (item 517 & 531 from SM) are working properly.


There is one last problem with this unit to call it fixed.

It's struggles to FF & REW. I found that is the upper brakes (the T shape brakes, item 425 from SM) that holding the reels.

The only way to fix it is by moving the pinch roller out of specs, closer to capstan by adjusting the rotary encoder.
(it's the pinch roller lever that is releasing the brakes)

SM is little confusing.
Its says it that the correct position for the rotary encoder is where the pinch roller touches the capstan housing in STOP mode.
The pinch roller will never touch the capstan housing. Will only touch the capstan in PLAY mode.

View attachment 2959786

I found that other people have the same problem but i didn't found a solution yet.

Hi Dimitris,
I am currently working on this mechanism. You need when the rubber roller presses against the ton-shaft, you need to tighten the large black gears (blue in the photo) a little more. And due to the spring of the shiny flat lever (in red in the photo), everything will stand up as it should, and then put the encoder gear in front of the point. Everything should work.

 

[LUX-X2]

Hello

I don't have any experience with the M100 but considering that it is similar to the 55ES, the drum should rotate as soon as the cassette shell is detected (switch S901 for the 300ES).

I have a manual dedicated to the 55ES, which could help with circuit description and troubleshooting, but it is too big to upload it here.

Send me a pm with an email address and I will send the file with Wetransfer.

Dear Hdrobien,

I solved this problem, the cause was a faulty encoder gear. Thanks for the help in recommending the manual for 55ES, for the fact that it contains a lot of useful information. I bought another SONY DTC-M100 deck. Now I have disassembled the entire mechanism, set the height of the adjusting white rollers using a micrometer (before disassembling, I wrote down all the dimensions). Replaced all the capacitors on the mechanism. I bought a SHARP DAT demonstration cassette, now i need to hire an oscilloscope.
Thank you for your help, friends!!!

 

[hdrobien]

@ Dimitris_said
Good to hear

The roller don't have to physically touch the casing (anyway, it can't as you said), but optically when seen from above.

The T-shaped brakes are only release in play mode, not during rewind/fast forward.

If your unit struggles, check that both reel hubs rotate freely (when all brakes are released, of course). If not, remove them and clean their axes and shafts

 

[hdrobien]

@ LUX-X2
It is vital to perfectly clean both black gears from the old grease, including their sliding spring-loaded arms and the "silver hook".

Don't forget to resynchronize both gears, inserting a rod in their hole and the one in the chassis.

They don't need to be tightened too much.

 

[Dimitris_]

The roller don't have to physically touch the casing, but optically when seen from above.

Hi hdrobien,

This is also my understanding re the correct position of the pinch roller by reading the manual.

However the unit struggles to FF and REW when the brakes are engaged. As you say, all modes except PLAY.

Of course i already clean the shafts and the hubs rotate freely when all brakes are released.


I wondering if the pads are harder than it should due to age? Should be hard to touch or soft?

BTW i also have a 55ES with exactly the same problem. Anything longer than 60min tapes and the unit can't FF and REW.

 

[Dimitris_]

You need when the rubber roller presses against the ton-shaft, you need to tighten the large black gears (blue in the photo) a little more. And due to the spring of the shiny flat lever (in red in the photo), everything will stand up as it should, and then put the encoder gear in front of the point. Everything should work.

Hi LUX-X2,

This doesn't sound right or i didn't understand exactly your point.

The position you are talking about is the PLAY mode. The rotary encoder should be aligned / set in STOP mode, where the pinch roller doesn't touch the capstan.

The microcontroller will push the pinch roller against the capstan in PLAY mode.

 

[hdrobien]

I wondering if the pads are harder than it should due to age? Should be hard to touch or soft?

BTW i also have a 55ES with exactly the same problem. Anything longer than 60min tapes and the unit can't FF and REW.

I would say soft, like felt.

You can also clean their surface contact n the reel hubs.

Be aware that both reel hubs are not identical.

 

[hcanning]

I have bought myself a DTC-60ES, just to play with. It's a gorgeous bit of kit and matches my Sony ES CD player with its wood sides.

It appears to work perfectly and records and plays through tapes quite nicely. I have bought a new belt for the eject mechanism as the belts are something I like to replace when I get a "new" old bit of hifi.

While I have it open is there anything else that it's recommended I do in terms of maintenance?

Thanks

 

[LUX-X2]

I have bought myself a DTC-60ES, just to play with. It's a gorgeous bit of kit and matches my Sony ES CD player with its wood sides.

It appears to work perfectly and records and plays through tapes quite nicely. I have bought a new belt for the eject mechanism as the belts are something I like to replace when I get a "new" old bit of hifi.

While I have it open is there anything else that it's recommended I do in terms of maintenance?

Thanks

Hi!
I found some very good instructions from a Japanese serviceman who repairs these decks and posts the repair process with recommendations and photos. Here is a link to repairs of DTC-59ES models:

link here!

There are on the page to the right other DTCs models and more..., there are a lot of interesting and useful things on our topic, this website in Japanese, but now it is possible to translate pages online.

 

[hdrobien]

The DTC-60ES (ie DTC-59ESJ in Japan) is among the latest models and is less prone to the usual issues like:
- bad smd caps in the rf amp
- bad capacitor on the power board (as the power board has been heavily modified and integrated on the main board).

However, if its transport benefits of some improvements over the previous generations (57ES, 59ES), it may still suffer from some issues like:
- loss of clips that hold the black and the white gears that move the guides.
- hardened grease on some gears

And remove the foam drum cleaner if it is still here.

 

[ROB60]

Hi all, I'm new to this group, and have only read the first 10 pages of this thread,
5 years ago I brought A Sony DTC A6 DAT Machine Second Hand, it arrived a bit damaged, all the buttons were pushed in,
but it worked fine with the remote, all functions were fine.
I moved house recently and put the A6 in storage for a year, when I put a tape in it played digital noise for a second and then stopped, it fast forwards or rewinds for a couple of seconds and the stops, so I took the cover off and took the attached photo's, the tape is not tight and the inside is dusty, can any DAT Guru's point me in the right direction

Thanks

 

[zerofox]

Hello. I have a Sony DTC-59ES DAT deck that works perfectly except for one thing. The fade light on the display flashes non stop when the unit is turned on. It is just the fade light without the fade up or down indicator. I have tried hitting the fade button to no avail. The fade light just flashes non stop regardless of whether a tape is loaded or not. It continues to flash non stop while playing too.

I’ve read the owners manual, service manual, and googled it but I have found nothing.

Does anyone have an idea what might be going on? I posted on a different forum, but did not get many responses.

 

[Dimitris_]

Hello. I have a Sony DTC-59ES DAT deck that works perfectly except for one thing. The fade light on the display flashes non stop when the unit is turned on. It is just the fade light without the fade up or down indicator. I have tried hitting the fade button to no avail. The fade light just flashes non stop regardless of whether a tape is loaded or not. It continues to flash non stop while playing too.

I’ve read the owners manual, service manual, and googled it but I have found nothing.

Does anyone have an idea what might be going on? I posted on a different forum, but did not get many responses.

Hi,

The fade light is blinking or is on all the time?

Because if its on all the time I think is normal.
My 55ES does the same.

 

[Dimitris_]

I would say soft, like felt.

You can also clean their surface contact n the reel hubs.

Be aware that both reel hubs are not identical.

Hi hdrobien,

Sorry for the late reply.

I found the problem with the FF & REW.

The pads was dirty and sticky. I remove the T shape bracket and clean the pads with some soap and let them dry.

Now working perfectly.

Only job left is to find a pre-recorded tape to check the head alignment.

 

[zerofox]

Hi,

The fade light is blinking or is on all the time?

Because if its on all the time I think is normal.
My 55ES does the same.

Thanks for the response. It is blinking all the time. From the moment you turn the power on until you turn the power off.

 

[Dimitris_]

Thanks for the response. It is blinking all the time. From the moment you turn the power on until you turn the power off.

Can't help more I'm afraid.

The correct behavior is that the blue fade segment is on all the time and when you press the fader button a red segment start flashing for about 4 seconds, while the machine fade in or fade out.


It's not normal, but it's a minor issue.