Best way to solve the X68000 PSU problems?

Started by amigo-mexicano, April 02, 2015, 01:53:06 PM

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Hello people.

I am a new X68000 user!

The X68000 is such a great machine, it feels so solid, even the keyboard alone. I bought a Super HD and an original grey model. I am very happy with them. So happy, an Expert HD model is coming too.  ;D I think I am the first in Mexico to have, repair and use X68000 hardware!

Ok, so now to the problems corner.The Super HD model does not turn on (just timer and power leds stay on in color red, nothing more happens, not even fan activity).

I've been reading all topics here (back to first page!) and I see the PSU problems rise and rise again, even if capacitors, diodes and transistors are replaced.

As for this PSU, all capacitors had a lot of leakage, I desoldered them, cleaned the board, and installed new ones, no luck.

I changed diodes, no luck.

I changed some transistors, no luck.

I bought today molex and other transistors and we'll see what happens, but result has been the same, no 12v power out the PSU, so, the same timer and power red leds only.

My question is: should I better forget about this PSU and go for a Pico PSU solution instead? What do you recommend guys? I mean, I might end up changing stuff forever, and as I've been reading, even if it works, it might fail again in the near future.

So, I ask the experts here. What do you think?

Thanks in advance.
From Mexico City... Amigo-Mexicano!
Also known as: "compil3r" ||


I got tired of repairing original power supplies that inevitably fail again.  Now I only do pico psu replacements.


Did you change all diodes , also the zener ones?It seems there are no schematics for this model of PSU.Anyway, they are badly engineered, IMHO the choice is between replacinng all the components ( I have done this for my ExpertHD and PRO) or replace the whole PSU with a picoSPU or miniATX.

Check also the optocouplers.



Quote from: BlueBMW on April 03, 2015, 02:35:50 AM
I got tired of repairing original power supplies that inevitably fail again.  Now I only do pico psu replacements.

Ditto, I did this after months of trying to get the PSU working and never looked back.
The additional benefit is my X68000 Ace now works at my native 240v  ;D


Thanks a lot for your replies!

Caius: I changed only the zener diodes. I bought the couplers and I'll try changing them.

Netwalka: I'll try that, thanks, I just bought some, hope I hit the jackpot this time.

BlueBMW & X-Col: I already ordered a Pico PSU... from China. So, while I wait the 1 to 2 months it always takes to arrive, I'll keep trying with new components on the original PSU. But, as you suggest, the complete change of PSU is better.

I'll do some work tonight and see what happens...

Thanks again!
From Mexico City... Amigo-Mexicano!
Also known as: "compil3r" ||


Going Pico-PSU way means usingn an external power supply?

I ask that because notebook power supplies that fit inside the X68K, and has enough VW power will fall in between 40-80 USD ? That is a lot for a PSU replacement.
Than you have the option to install Pico internally, and re-use the same external PSU.

If that is the case, then I would rather go with an internal low profile ATX - that would keep computer as original and it is cheaper.

Said that, I am yet to try Pico PSU, but only if it is worth to use an internal PSU.


I use an external brick with the pico psu.  You can do a clean modification to the system to use the external brick and not look bad.  I even wire the 12v input to the switch on the back so that it is still functional.


Bad news. I changed everything and still same problem. Timer and Power leds stay lit, doesn't turn on at all. No 12v power.

I could try and change all remaining diodes, it is worth the shot or I just give up on this power supply?

From Mexico City... Amigo-Mexicano!
Also known as: "compil3r" ||


Been there, done that, gave up.
Do yourself a favour and follow BlueBMW's advice and go the Pico route  ;)


Enough with this old power supply. I am going to try this adapter I just received, while I wait for the Pico PSU. Using this adapter NOW, I will make sure that the X68000 works, maybe the problem is somewhere else (hope not!)...

I will test tonight and update the horror story!  ;D
From Mexico City... Amigo-Mexicano!
Also known as: "compil3r" ||


Finally, it was hard to let go of the original PSU (I wanted to keep the X68k as original stock as possible), but it was worth the pain.

First the installation:

And then, the magic!

I was SO happy to see that green light!

At first, both the timer and power leds were on, as before, I guess in fact the X68k had a timer programmed on SRAM, and that scared me, what if it didn't turn on even with new ATX PSU?  :(

But when pressing the red power button on front, green led bliss. YEAH!

Now, I am testing with many floppy games, and I'm having another problem. I will detail that on a separate post.

Thanks for all your help guys, another X68000 is back from the dead, and living happy in Mexico City!  8)
From Mexico City... Amigo-Mexicano!
Also known as: "compil3r" ||


Nice to see another dead x68000 brought back to life!  :)