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Adapting Sony 40-Pin SLCD Proprietary CD-ROM Iinterface for IDE Compatible Drive

NTL1991

New Member
Joined
Nov 8, 2013
Messages
7
Location
Rhode Island, USA
Hello,

I've got a bit of a problem. I'm in the process of getting a piece of GenRad automotive test equipment, more specifically, a Jaguar PDU (Portable Diagnostic Unit) from 1993 up and running. The problem is not with the touchscreen PDU unit itself, but rather the "base station module" which houses a power supply that powers and charges the PDU's internal battery, as well as an interface card and Sony CDU-535 CD-ROM drive. Before using the PDU, the technician will load the correct vehicle diagnostic CD-ROM and caddy into the CD-ROM drive, connect the 4-pin data/charging cable between the PDU and the base station module, and turn the PDU on.

The base station CD-ROM reads the data and sends it to the PDU where it is kept in memory. The technician can now disconnect from the Base Station Module and move to the vehicle with the PDU for diagnostics.

My problem is that after loading any of the 10 CD-ROM's I have for the PDU into the base station, the Sony drive sucks them in, whirrs them around three times, then ejects the CD and caddy. I've opened up the drive, and it's dust-free inside, the lens is clean, and as far as I can see, all the motorized parts move as they should.

The drive is powered by a standard Molex connector from the power supply board inside the Base Station that also charges the PDU. The Sony CDU-535 drive has a 40-pin interface that connects to a standard IDE style ribbon cable, which is soldered to the interface PCB.

I thought "Hey, why don't I just install a modern CD-ROM drive", thinking that it was a standard IDE interface. This is not so, the drawer on the new drive would not open and the status LED was lit constantly. I did some research and found that the original Sony drive, made in 1993, uses a proprietary interface, called SLCD. I've also seen this term used in conjunction with Panasonic drives with proprietary interfaces too, which is confusing...

I have a nearly identical Sony CDU-541 handing around, and decided to take it apart and look inside. To my surprise, both are mechanically identical. The only difference between the two is interface. The CDU-535 uses the proprietary Sony 40-pin interface. The CDU-541 has a SCSI interface. I swapped the PCB boards from the drives to rule out mechanical failure. All connectors are exactly the same.

The CDU-541 mechanics with the CDU-535 PCB does the same thing. So I put it all back to original.

So that's as far as I've gotten. Aside from looking for a working CDU-535 which I think is nearly impossible at this point, I'm interested in other options. Is there any way to adapt the Sony interface to an IDE compatible one, whether it's modifying the ribbon cable to match the correct pins up, or otherwise?

I can't even find any pinouts for the 40-pin SLCD interface, only for their other 34-pin proprietary interface. I'm not sure of the difference between the 34-pin and 40-pin Sony interfaces... Eventually, the data from the CD-ROM is sent over two pins to the PDU. I'm wondering what I'd have to do to get a standard IDE/ATAPI CD-ROM to send the correct data over these two pins to the PDU. I'd love to be able to get a modern and reliable drive installed in this base station.

I have heard of a gentleman who had the PDU unit itself and all the cables, but no base station. He built a power supply to power/charge the PDU and the CD-ROM drive, and also bought or created an interface card to work with a standard IDE drive. Not sure how he did it, though, but I've inquired and I'm hoping to find out.

I did purchase a used Sony CDU-6250 dual-drive external setup from eBay. According to the very small amount of information on the web about these older Sony drives in general, I found that the drives used in this dual-drive example are in the CDU-535 family, and use the 40-pin Sony interface, and I'm hoping that after removing them from the enclosure, at least one will work for me.

Any ideas on this situation?

Some pics:

The PDU and Base Station:
$_57.JPG


The power board and Interface board inside the Base Station Module:
IMG_2035.jpg~original


The Sony CDU-6250 that I've purchased:
$T2eC16ZHJGoE9nuQgjUjBQvUkotfz!~~60_57.JPG


Rear of Unit with Correct DRQ/WAIT, Terminator selections also used on the Internal CDU-535 drive:
$T2eC16FHJGkE9no8fyypBQvUlJWM5g~~60_57.JPG


The Rear of the Original Sony CDU-535 drive from the Base Station. Notice the same pins for selections as the external unit:
IMG_2034.jpg~original


Thanks,
Nick
 

NTL1991

New Member
Joined
Nov 8, 2013
Messages
7
Location
Rhode Island, USA
I did a little more Googling and found something interesting in a Users Manual for a SoundWave 32PRO Sound/CD-ROM Interface Card by Orchid.

There's a note with the interface:

"NOTE: The Sony CD-ROM connector only has 34 pins. If you received a 40-pin cable with your Orchid or Sony CD-ROM drive, several pins will hang over the connector. Those pins are not used. Just be sure to line up Pin 1, and let the excess pins hang off the other end of the connector."

So I'm guessing pins 34-40 on my drive have no function? Does that theoretically mean I could use a 34-pin Sony drive as long as I modify the cable to suit? I'll have to check the interface PCB on the drive and in the Base Station to see if there is any circuitry to these pins.

If this is all true, my question would still remain the same. Would it be possible to convert or adapt a new IDE CD-ROM drive to a proprietary Sony 34-pin interface?

Thanks again,
Nick
 

NTL1991

New Member
Joined
Nov 8, 2013
Messages
7
Location
Rhode Island, USA
And more fiddling around...

My own Sony CDU-541 (SCSI interface), when plugged into power will spin all of the discs that I've been trying to read no problem. I don't have a PC with an ISA slow for the interface card, but at least it doesn't eject the Caddy after putting it in.

So, I removed the CDU-541's SCSI PCB board, and installed it on the CDU-535 drive. After powering it up, and testing with a CD, it too, now reads the CD and keeps it spinning. No errors and no ejecting...

So both drives have tested out with working mechanicals. I put the CDU-535's SLSC PCB in the CDU-541 drive, and after putting a CD in, it ejects it right out...

So the problem with the CDU-535 is stemming from the PCB in the drive. What sort of PCB malfunction would cause a drive to not recognize a CD-ROM and eject it right away. Like it said earlier, the spindle motor will spin the CD for a second or so, stop, and repeat another two times before ejecting the caddy. It sounds to me like I have a faulty IC or something of that nature on the CDU-535's PCB.

Nick
 

luckybob

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Joined
Feb 3, 2009
Messages
1,326
Location
denver
I did a little more Googling and found something interesting in a Users Manual for a SoundWave 32PRO Sound/CD-ROM Interface Card by Orchid.

There's a note with the interface:

"NOTE: The Sony CD-ROM connector only has 34 pins. If you received a 40-pin cable with your Orchid or Sony CD-ROM drive, several pins will hang over the connector. Those pins are not used. Just be sure to line up Pin 1, and let the excess pins hang off the other end of the connector."

So I'm guessing pins 34-40 on my drive have no function? Does that theoretically mean I could use a 34-pin Sony drive as long as I modify the cable to suit? I'll have to check the interface PCB on the drive and in the Base Station to see if there is any circuitry to these pins.

If this is all true, my question would still remain the same. Would it be possible to convert or adapt a new IDE CD-ROM drive to a proprietary Sony 34-pin interface?

Thanks again,
Nick

take a look on the bottom on that board, if what that sound card manual says is true, then i'd bet pins 35-40 will be not connected or tied to ground. (most likely not connected.)

if I was in your shoes, I'd give it a shot.
 
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