exxos's Atari, Amiga & retro forum

Hi have a couple of Mega STEs, 1 in bits 1 complete, The complete one sometime flickers when I open the hard disk I thought the hard disk might be failing as its the original so I have put a bluescsi in and it does the same with that. I tried a ultra-satan and again the same thing. It only does it every know any then is likely to be a DMA issue maybe a PSU? (I have a third scrap mobo so I might have another DMA if its not damaged I might try it).

Thanks

Brian

I've read your extensive article on DMA so I would be looking at a PSU, CPY or DMA I'll check my scrap board on the weekend and see what the state of the CPU and DMA are and maybe try swapping them over failing that I'll go through the PSU. You put in a lot of work on DMA's thank you Mr Exxos.

Can you be a bit more descriptive, when you say 'it sometimes flickers when I open the hard disk' ... What sometimes flickers?

Steve wrote: 21 Mar 2025 07:18 Can you be a bit more descriptive, when you say 'it sometimes flickers when I open the hard disk' ... What sometimes flickers?

I'm with Steve, what flickers? The screen is all I can think of, but if software is working, but the screen is flickering, I can't imagine it being something like DMA or CPU.

Power seems more likely to be the cause to me. Or caps.

A video of the symptom would help.

Usual steps apply, power, clocks etc & remove any socketed ICs clean the pins, tweak the PLCC sockets, spray with contact cleaner and reassemble.

Is the Ultrasatan externally powered (ie. not drawing power from the MSTE)?

BW