Need help with "dead" PlayStation prototype unit

I got one of the prototype units in grey case. The unit looks like showed here but my unit is DTL-H1200.

https://www.assemblergames.com/forums/showthread.php?24030-SCPH-1002/page2

The unit shows nothing. My Sony PVM detects NTSC signal but I see just black screen and no sound.

When I opened the unit, I saw that serial numbers inside and outside are not the same. Okay... I noticed that cable which connects main board with CD-ROM transport is damaged. The installed transport is KSM-440AAM. I have no idea, why Sony used so old transport.

I tried to install the transport from my working SCPH-1002. It changes nothing. I tried to replace power supply using the supply from SCPH-1002. Still nothing.

What can it be?

 

It sounds like you have a unit that has had parts swapped on it - those DTL-H120x machines should have a KSM-440ACM pickup assembly in them, and the serial number on the top shielding normally matches the one on the label.

The first thing I would try is to plug it in with a known-good PSU and the video cable attached and check the fuses to see if any of them have blown.

It's also worth checking the numbers on the CD-ROM controller ship to make sure someone hasn't swapped a retail board in there - the first line on the chip is normally a letter followed with a 4 digit number. It should be something like "D 2021" - it it starts with a "C", then it's a retail board.

 

I made some pictures of the unit. May it help?...

http://s27.photobucket.com/user/psx-collector/library/PlayStation DTL-H1200 Prototype?sort=3&page=1

 

You must take photo of the rear motherboard, in particular, as TriMesh wrote, the CD crontroller photo

 

Done. Last five pictures.

http://s27.photobucket.com/user/psx-collector/library/PlayStation DTL-H1200 Prototype?sort=3&page=1

 

OK, that's one of the first-generation test boards they shipped out to developers when they were first testing the Rev. C silicon. Although it's marked "PU-9", it actually comes between the -1x and -2x PU-8 production. That CD controller is an OTP type (the number is covered up, but it's going to be MC68HC05L16 - and they don't have the "D xxxx" numbers on them.

The first thing I would try is to just plug the main board into the PSU and check the voltages on both ends of the fuses soldered to the main board - there are 5 of them, all close to the PSU connector. Note that you don't need the CD unit or the controller ports connected for this - it should boot with just the PSU connected.

 

I put a BAM in my unit, no issues at all.

Sadly I sold that unit on, no idea why I did. :c