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NFG Forums => SIG X68000 => Topic started by: X-Col on January 21, 2026, 03:15:44 AM

Title: Compact XVI PSU issues
Post by: X-Col on January 21, 2026, 03:15:44 AM
It seems the PSU on my Compact XVI has finally died :-(

I recapped it when I purchased it around 2014 and it has worked great since then. However, recently the power started to cut out randomly with no red standby light on the system.

The next day I would try and it would be working again. Not usually for long however. Today there is no power at all.

X68000 power supplies are usually problematic and I'm not good at tracing problems with them. So I would like to do a PicoPSU ATX conversion and drive the Compact from a 12V DC adapter.

Are there any PicoPSU solutions for the Compact model? I did convert my ACE to PicoPSU and have had no problems with it.

The PicoPSU PCB for the Tower models will not fit in the Compact PSU case however. Is there a PCB for the Compact?

In the meantime I'll use my trusty ACE.

Thanks

Update: I have removed the PSU and confirmed there is 0v from standby power. Some component has obviously expired
Title: Re: Compact XVI PSU issues
Post by: kamiboy on January 21, 2026, 06:20:09 AM
I got my compact around 2012, and recapped it. Still working flawlessly, knock on wood, but should it ever fail I wouldn't do the external 12V PSU, for sure. I would hate to convert a perfectly neat all internal PSU into a partially external abomination.

I would likely just design my own PSU by modifying an existing solution out there. It has been over 10 years, so my memory is hazy, but I recall that the X68000 compact only needs 5V to operate, so a PICO is kind of silly. I would probably prefer to use one of those all in one modules that take 220-100V volts in and output 5V at a high enough amperage, then use a micro-controller to handle soft power on and off. Not sure exactly how the soft power on the compacts work though, so it might be more complicated than I imagine.

Anyway, it is strange that no one else has done this yet. Are people really happy to ruin the aesthetics of their beloved X68000 with laptop power bricks?
Title: Re: Compact XVI PSU issues
Post by: X-Col on January 23, 2026, 01:52:52 AM
I would like to keep the Compact original to be honest, but don't really know how to diagnose the problem with my original PSU

I did find a cold solder joint on the K1101 mosfet and have resolved that. However, it still does not work.

I'm wondering if that cold solder joint has killed that mosfet?
Title: Re: Compact XVI PSU issues
Post by: kamiboy on January 23, 2026, 02:00:09 AM
Hard to say. Other than capacitors the components that most often fail are voltage regulators, such as the one you mention, then there is diodes and resistors.

Fortunately those components are quite easy to test if you can remove them from the PCB. There are component testers sold on AliExpress that can test the components and they cost very little. Might be worth a shot.
Title: Re: Compact XVI PSU issues
Post by: X-Col on January 23, 2026, 03:10:13 AM
I removed the K1101 and tested it using this method https://www.homemade-circuits.com/how-to-check-mosfet-using-digital/

It seems to not be working, would this suffice as a replacement?
https://www.ebay.co.uk/itm/225089480419?_skw=k1101+mosfet&epid=1493651349&itmmeta=01KFK83QYJG1Z5RCYAH0DMQHGX&hash=item346860e6e3:g:rNgAAOSwf3pgE958&itmprp=enc%3AAQALAAAA4O7PUuNWmJ%2B%2BUShgI9tQz%2Fq5RBmRkoB2y4GJNkiXz58QEIXfE0Ce8E0pMbuUx6VpnCMCkf3ETnJew%2B2VBNXavi6K7s4PS4HdBff6GCn2K6ylUYD2FYLOkkdDtiGOjXtD5LD9rbVLJmrcR44sgzjmFdlySeWd0Mk%2BTmuH62mLUdSSqS9kcHLQWY%2BVNQNl2CX8c4Whs2L1dH9DfPGbzBpY%2BaO1BfB8xTfP9gvaH%2B0C0AtKN8LhTRp1I4QgYwnYWPRFnOb0TQacIayHe%2FtiLGVNHq2TAb20Z6O5zXsx1dL43z%2Bl%7Ctkp%3ABFBMxP-O6Pxm
Title: Re: Compact XVI PSU issues
Post by: kamiboy on January 23, 2026, 03:30:11 AM
Seems to be a drop in replacement. To be absolutely sure you could find the spec sheet for yours and the replacement and check.
Title: Re: Compact XVI PSU issues
Post by: X-Col on January 23, 2026, 11:02:17 PM
I ordered one, looks like the right part number.

Hopefully this transistor is the problem!

Thanks for your help :-)
Title: Re: Compact XVI PSU issues
Post by: kamiboy on January 24, 2026, 03:20:37 AM
If you have a lot of vintage hardware I recommend you get that component tester for future diagnosis. It is a great tool.