Servicing a SONY DAT machine (Pictorial)

[Dimitris_]

So I found this device called a Elketor Copybit Stripper that was manufactured some 15-20 years ago specifically so people could copy from a digital source to DAT. I found the schematics, PCB layout and BOM but I can't find anyone who actually has the PCB files to have the boards manufactured. Anyone know much about them?

Here you go (Not tested):

Changes are:
Added J1 jumper on the power rail that can be used to add a power switch

Optical receiver module is replaced with TORX178B

Pardon Our Interruption...

Optical transmit module is replaced with TOTX178A

Pardon Our Interruption...

Resistors R30 to R36 are replaced with a resistor network

https://www.aliexpress.com/item/32437484468.html

"A08-103 10K" variant

RCA Plugs:

https://www.aliexpress.com/item/1005006135592165.html

"Q-yellow D" variant

EPROM is replaced with EEPROM (optional) WINBOND DIP-28 W27C512-45Z:

Pardon Our Interruption...

Source for the EPROM file / Credits for reverse engineering:

Elektor copybit stripper

Apologies if this is not the right place for this. I'm trying to help a friend out with a project, he's trying to build one of the copybit strippers that was published in Elektor about 20 years ago detailed here http://www.minidisc.org/copybit/copybit.html It's a clever design that uses a ROM bas...

forums.sonyinsider.com

 

[hdrobien]

From my understanding, the 300ES is designed as the 1000ES and just can't record 44 kHz from digital inputs, whatever a copy protected flag.

The SCMS which first appears with the 55ES, unlocked the feature (recording in 44k from digital inputs) but with the known limitations.

 

[macsonny]

From my understanding, the 300ES is designed as the 1000ES and just can't record 44 kHz from digital inputs, whatever a copy protected flag.

The SCMS which first appears with the 55ES, unlocked the feature (recording in 44k from digital inputs) but with the known limitations.

Ahhh, you were 100% correct. When recording from my laptop at 48 kHz it does in fact start recording. Thank you!

But now next problem. It is recording but it seems to be a bit "jerky". If you watch the attached video link you'll hear that it records for 1 second then nothing then sound returns. I also noticed that it's starting to chew tapes when rewinding. Probably two issues.

Is there an adjustment I can make to resolve the recording issue?

I'll investigate the rewind issue and see what I can find.

Thanks

 

[hdrobien]

I see a problem while playing a recorded tape.

Could you play the tape on another deck to check the recording itself ?

 

[macsonny]

Could you play the tape on another deck to check the recording itself ?

Unfortunately I only have on DAT unit so not able to test on another machine. I have tapes that have been recorded on another DAT that seems to play ok on my machine.

I've purchased some DAT head cleaning tapes to see if that will help my cause.

 

[mattdemath]

Unlike all other models, there is no chemical smd capacitor in the head amp (rf amp) in the 1000ES, only tantalum.

So I expect the same in the 2500, and that is (probably) why 1000ES rf amps never fail.

View attachment 2248001

Hello,
I didn't shoot any pic of the Drum Drive Board on the old PCM2500 I'm fighting with, but I remember there were 4 SMD 10uF/16V electolytic caps.
The trouble I am experiencing is:
- cassette loads OK, after I changed the drawer motor belt (old and loose: tray needed help). Capstan motor spins, it starts then stops because:
- Drum doesn't rotate, neither take-up reel nor supply reel.

Side question: what the hell is the heater at the base of the drum for? DMM showed a mere 0,03 ohm resistance, and indeed, I don't measure 9Vdc coming from Servo MD board as stated by the service manual. I disconnected the heater (2 wires), measured 12V, but got a "CAUTION" displayed on the panel right away. And still no spinning of the drum or reels.
Do you have any clue, Mr De Robien?
Thanks in advance.
Matt
Thanks

 

[hcanning]

My DTC-60ES works perfectly except occasionally (usually if it's not been used for a little while) when I eject it the door opens and then closes again. It's as if it hasn't quite got enough grunt to fully open it. I'm assuming it's the loading belt that needs changing. Does that sound about right?

As I say, everything else about it works spot on, playback and recording. Anything else I should do while I'm in there?

 

[hdrobien]

Hi
I would clean the end-course switches with contact cleaner.

 

[hcanning]

Hi
I would clean the end-course switches with contact cleaner.

Thank you. Can you point me in the rough direction of where I might find those?

 

[hdrobien]

They are located on the left side of the transport.

One is activated when the door is fully opened, the other when the door is fully closed.

 

[hcanning]

I have now resolved my DTC-60ES door opening issue. I gave it a new belt, cleaned the dust out, and added small amounts of silicone grease to all the plastic sliders and arms that move when the loading mechanism operates. It now opens all the way beautifully, activating the little end course micro-switch nicely.

I initially thought it was the motor wearing out and not being able to provide enough torque do to this *and* overcome the spring that holds the outer door open, but it seems it's all good!

Everything else inside looks spot on, and I left the head alone as it plays perfectly without any skipping. Even the foam head cleaner roller is still perfectly intact.

 

[Nazar1980]

Fixed it already.

 

[hcanning]

Fixed it already.

Stick a brief explanation of the issue and how you fixed it here. It might help someone in future

 

[SaSi]

I thought I'd spend some time with a couple of DAT decks I fixed a few years back and, low and behold, they were not playing properly any longer. The muting relay kept on kicking in. I knew they were properly calibrated and had the heads cleaned, so my suspicions went to the head preamplifier capacitors that I never bothered to replace.

Long story short, all the 22uF/6.3V capacitors in that board were out of spec but fortunately not leaking.
This was my first go on replacing SMD capacitors and I've only had the experience of viewing how others do it. Some decapitate them with a cutter, others try with hot air gun.
I thought I'd use my "needle sharp" "bit" for my soldering iron and try to unsolder them. It works, with a fine tip and I think it's better to have a soldering station with adjustable termperature. I found 350C was fine.

Onto the matter now. I only had 22uF/25V through hole electrolytics so I did what I could with them. Had to leave one on and also the 4.7uF one.
The old capacitors were reading about 100uF with a 30-40Ohms ESR, so they were really sinking current and boiling what was left of the electrolyte. Save for one that had lower capacitance reading than ESR. I suppose it got bored being a capacitor and decided to become a resistor.

Even with two of the old caps on the board, I went on and tested it and although the sound isn't restored, it is mostly and the muting relay doesn't kick in. So, I need to order about a hundred caps to do the various boards. Went to Mouser and found I could not find any. Through hole caps of 22uF start showing from 63V and up. Nothing small is available.

So, I'm thinking.
Do I go for equivalent SMD caps to put there or could I try tantalums? These are still available, in reasonable price at 6.3V and I know I can solder them. But will there be any issues by using these - taking into account that there are RF signals there?
I'm tempted to try SMDs, just because I've never done this before (can you see the rabbit hole?) and it might be fun (probably not). Like I said I don't have SMD equipment or solderpaste. So it will be caps + tools + consumables.

I'd really like to get it done and tantalums appear to be the quick path. But will it work? (I know what some might say: Just try it man!)

 

[hdrobien]

I use tantalum smd (size B = code 3528) for years, and they are just fine.

 

[SaSi]

Thanks, that's what I'm going to order then. SMD all the way.

 

[SaSi]

I don't know what I did wrong in my first search in Mouser, but upon a second one it presented a lot of small voltage electrolytics. So I order a complement of these, plus SMD ones, just to give a go with those. Didn't fix those RF amps when my eyesight was 20:20, but I will do it now.

In the meantime, I'd like to share an experience with the PCM R500 deck I have that was working wonderfully a few years back but showed issues when brought back to service after 5 or so years in storage. I would "play" very fast, like in FWD search mode for the first half of the tape and would play some for the second half of the tape length, but with lots of errors.
It was clear that the pinch roller was skipping, so I took it out, intensely cleaned it, applied rubber renew and even took it through a sand paper but it would not play ok. I did have a couple of spare rollers for Sony decks from back in the past, so I just dropped on in place, and that was all it needed.

Lesson learnt: When a DAT deck needs a new pinch roller, it really needs it. No free lunch to be had here.

 

[hdrobien]

I fully agree with you about the pinchroller, especially since we can find new ones of good quality.

 

[chorazy3]

Pioneer D-05 i bought few months ago, that worked fine then, sit unused, developped problems.
Firstly it didn't play, head didn't rotate, it didn't retract the tape back inside when I pressed eject. After few attempts it started working.
Unfortunately it has severe dropouts. It plays fine everytime for a couple of first few seconds (even up to 10 sec.) but then lots of dropouts, long ones. So I presume the head is fine and the problem is with tape path. Cleaned the drum and the tape path to no avail.
Cleaned and relubricated: slant block arms (they fell in the docks nicely), capstan, pinch roller shaft and reel tables (found that black gummy stoppers turned to goo, replaced them). Cleaned rotary encoder. SMD caps were already replaced.
Also without effect.
I can see that the tape doesn't run smoothly on the right side white nylon/ceramic roller although it seems to run smoothly on the pinch roller, it's surface looks ok to me.
What can be the culprit? Too small take up tension? Weak capstan/reel motor? I have no test tapes.

 

[ARC Tech-109]

Have you actually looked at the RF pattern from the head amplifier using a scope?