exxos's Atari, Amiga & retro forum

Have also also tried what I said in this post ?

https://www.exxosforum.co.uk/forum/viewt ... =10#p17474

yes i tested alls, ACSI test software on 8Mhz OK on boosted KO. I tried old SIMM RAM 2x256KB with 8xdil chip - still the same. Blitter chip on off no effect. Only PSU no tested, only with voltmetr 5.06V.

What was the result for removing the CE wire ?

nothing happens, still the same

What is the value of P100 resistor pack at the front of the motherboard ?

A122J - 1.2Kohm

The only other issue I know is a fault I found on the STFM a few days ago. Where A1 had some issue when running with the booster. So you could try a 390pF capacitor on A1 on the DMA chip to see if that helps. If that fails, then I'm afraid you will have to find a different motherboard. The ones with external blitters seems to have less issues than the integrated boards.

I do not think there is anything else to actually try.. I suggested all the faults I know of. But as said before, the booster itself does not really have anything to do with the DMA circuit. But these DMA related problems are very difficult to track down.

A1? Pin 1 on DMA chip?

nemox wrote: 05 Feb 2019 19:16 A1? Pin 1 on DMA chip?

A1 is pin 2 on the DMA. Connect 390pF capacitor (220pF should be OK also) from pin 2 on the DMA to 0V.

thanks