Disc does not spin

[VideonelloS10]

Hi everyone, I'm a Saturn owner since 2015. I have two of them, both are VA9 PAL versions. One of these has a faulty motherboard, so I changed it using a VA15 JAP that I recently got from eBay.

I've installed the mobo in the faulty Saturn, it turns on normally but the disc does not spin.The cd reader works when is attached to the faulty VA9 PAL mobo, when it's turned on the laser goes back to the start position, then it spins the disc and reads the TOC of the disc. Then nothing happens because all I got from this mobo is just a black screen.

When I attach the cd drive to the japanese mobo the laser does no go back to the start position and I see big red spheres in the menu (sometimes on the left and sometimes to the right) and I see the OSD message checking disc (see photo below). According to some posts in this forum, it looks like an issue regarding the cd player that motherboard cannot use the cd player. I also listen some pop and crack noises especially during the boot.

I tried to change the 21 pin data cable too, but nothing happend. The motherboard is still unable to use the cd player.

What can I do now?

[zyrobs]

The CD drives are not compatible between those boards, their pinout is different.

[VideonelloS10]

Thanks for your reply. So do I need a VA9 japanese motherboard in order to make the cd drive works?

[zyrobs]

Between VA6 or VA9, yes. VA9 can be converted to PAL (it's a universal board), VA6-7-8 will only work in NTSC mode.

[VideonelloS10]

According to Segaretro, in VA9 machines I can use only these two cd players:

JVC ENR-013A EMW20035-002 610-6185-20
Sanyo 610-6185-30

In the faulty machine, instead, I have a VA2-5 cd player, this one: JVC ENR-011A EMW10589-002. When I turn on the motherboard it reads the TOC. But how is that possible? Maybe this player is compatible with VA9 too? Probably the previous owner changed the cd player.

[zyrobs]

The pinout is different.

VA2-5 drives use the same pin for both data and audio sync (pin 14), and have one pin for access led (pin 9).
VA6-9 drives omit the access led pin, and instead they use two separate pins (pin 9 and 14) for data and audio sync.

However, from memory, the VA6-9 drives (the JVC ones at least) use the same signal, they just split the trace to both pins, while the VA2-5 units do the same but on the motherboard. So perhaps with some modding, you could get the VA2-5 JVC drive working with a VA6-9 machine. Disconnect the trace going to the access led pin, and solder a connection between that and the other sync pin (pin 14). This is entirely untested and I'm going on from my memory and my drive notes - but it probably works because I could once connect a VA2-5 drive to a VA6-9 unit with a modchip between the two.
Also remember that the ribbon on VA2-5 drives is folded to reverse the pinout, though I think it's reversed on the motherboard side, so you should be good - not sure.

None of this applies to VA10-15 drives/motherboards however, which have the main clock signal generated differently, so they are completely incompatible unless you hack in an appropriate clock signal onto pin 1 (it's why the cheapest modchips, that had no onboard timing oscillator, required an extra timing signal wire).

[VideonelloS10]

I've found on eBay a cd unit marked as JVC EXL-P608. Does this model works with my VA15 motherboard, right?

[zyrobs]

According to my notes it should. It's the drive with the white stripe on the edge, right? That's the one used in VA10-15 machines.

[VideonelloS10]

Sept 16, 2019 15:34:37 GMT zyrobs said:

 It's the drive with the white stripe on the edge, right?

Yes, it is. Thanks!