Exxos PSU (2019), STE 1040 (1991), only works on reset

[kianryan]

Hi all,

I'm installing a new Exxos PSU [0030] in a 1991 1040 STE. This is a STE with a ST processor and all chips soldered on to the board.

This machine was working OK with the stock PSU, but being of an age, I'm keen to replace it.

The new PSU is giving me a nice clean 5V and 12V.

For testing, I've just got the motherboard on a workbench with the PSU attached, and a VGA adapter on the monitor port.

On initial boot on colour, I'm presented with either on-screen garbage (10% of the time) or a plain white/grey screen.
On monochrome, the screen is blank.

However, if I press and release the reset button, I'm immediately dropped in to TOS. The length of time the reset is held down for is irrelevant.

Any ideas why this is occuring, if this is a problem and if there's anything I need to do about it, or if it's a behaviour I'll need to live with?

[exxos]

You need to replace the caps in the reset circuit. Its listed in the fixes section.

https://www.exxosforum.co.uk/forum/viewt ... =17&t=2175

[kianryan]

Thank you.

This resolved the reboot issue.

Now on to a DMA issue, with a CA401177 (I'll post a separate topic).