X68000 cz600ce black screen

[agemon]

Hi, i would like to get some help to get a og grey x68 running (brough as junk).
The computer show some sign of life: when i press the psu buttons (behind), the power led go red and when i press the power buttons the power led go green and the high reso led go red.

I connect the x68 with a vga adapter to a crt monitor who detect something but black screen, same with an upscaller (sync on something but no picture).
I just recaped all the board (not the psu and the floppy drive) and changed the cristal near the battery. The second floppy drive as the edge connector broken (the one with the floppy ribbon).

Is there something i can verify or test?

[HIggy]

@agemon are you using the original PSU?
I have repaired 3 X68000's and the PSU's usually are a leaking mess!

Also on the OG X68000 I replace 2 logic chips near the crystal. I saw someone else did this, as the battery acid can crawl up inside the chip legs and destroy it. Sorry I don't have the info on me, but I probably posted it here on the Forum so you can probably search my posts.

Maybe look at this first.

You should get some Japanese text and a disk icon. But X68000 behave very strangely until their SRAM (bios settings) are configured. And they will have been lost.

There are also tiny capacitors inside the disk drives. I find they do leak.

Good luck

[agemon]

I use the original psu, i should recap it before the rest. I will also look for the 2 logic chip.
Thank for the reply.

[kamiboy]

How is a CZ-600 power supply even still running with its original capacitors, those should have leaked and given up the ghost 10-15 years ago already.

I seem to remember that the X68000 needs to detect both floppy drives to boot correctly so the broken ribbon cable might be you culprit, but I dont remember if it will just freeze on black screen or throw up an error message if so. The fact that the soft power is working means something is working on the PSU, but definitely recap it, and see if you get anything on the screen when you push the interrupt button. Just to see if the CPU is running or not.

For proper diagnosis you would need tools such as an oscilloscope. But to begin with you need to establish how much of the system is working. If the video out is broken but everything else works it should be able to boot off of a floppy. You could try and see if it starts reading from a bootable floppy inserted into the working floppy drive. Also, you might as well recap those drives, you will need them to do anything on a CZ-600 as they cannot boot off of external SCSI drives without a driver loaded, and currently the only viable way of doing that is via a working floppy drive and a copy of the MasterDisk.

[aotta]

Which crystal did you use? If it's not the exact frequency or it doesn't work fine, you'll have black screen. Also, there are a lot of tracks near the battery that could be damaged by the alkaline leakage, you should check them firstly

[agemon]

i replaced the one near the battery: 69.552MHZ
There was no noticable corrosion from the start appart some on one of the leg of the battery. I need to try without the floppy connected too, because like i said the edge connector on the second drive is broken clean (alredy broken when i got the machine), perhaps the x68 hang on some test or something and dont boot because of it.

[aotta]

Yes, without floppy connected, you should get the white rectangle with floppy icon on screen.
Just for curiosity, where did you get the right 69.552mhz quartz? I had to build one programmable for fixing one of my cz-600!

[agemon]

digikey https://www.digikey.fr/fr/products/detail/ecs-inc/ECS-P145-BX/965972
I cut pin 1 and isolated it like i have seen on some post

[aotta]

digikey https://www.digikey.fr/fr/products/detail/ecs-inc/ECS-P145-BX/965972
I cut pin 1 and isolated it like i have seen on some post

Thank you, i also bought from digikey this quartz already programmed in past years, but then i found it out of stock, and thought it was discontinued. Happy to know it's available again!