exxos's Atari, Amiga & retro forum

@Badwolf
Aha! I have to redo the measurements with 16ms/s. I had several sessions at the bottom but i guess it only saves the session that is active. So what you are looking at is the last session where i was pressing reset while probing it.

zChris wrote: 14 Jul 2022 20:03 @Badwolf
Aha! I have to redo the measurements with 16ms/s. I had several sessions at the bottom but i guess it only saves the session that is active. So what you are looking at is the last session where i was pressing reset while probing it.

32 if you can get there.

Clock should still be oscillating even in reset. AS should be high.

BW

Here i have used 16ms/s as per BadWolfs advice. There are two files one recording RESET HALT AS BERR on a good atari ste with coldboot and three resets with the resets button, and another recording but on the bad atari.

Can be downloaded here https://www.dropbox.com/scl/fo/162fff6b ... ueto4xhz7w

Good news! Did some ohm measuring on the pins of the 68 cpu and it turned out that A16 was shorted to ground and i luckily found it pretty quick. Was some solder on P102 it seems. So now im getting into TOS. Now i just have to find a DMA that is not IMP to test.

Thanks for all the help and time i've gotten :)

:bravo: :girldance: :girldance: :girldance:

zChris wrote: 15 Jul 2022 23:35 Good news! Did some ohm measuring on the pins of the 68 cpu and it turned out that A16 was shorted to ground and i luckily found it pretty quick. Was some solder on P102 it seems. So now im getting into TOS. Now i just have to find a DMA that is not IMP to test.

Thanks for all the help and time i've gotten :)

It's definitely worthwhile investing in a decent magnifying glass or microscope :)

Glad you found it :)

Unfortunatly the original problem is not resolved.

Maybe the USatan i have have something against original ataris? It does not work on two STe, which both having HC cpu and one of them have the resistor fix on it. Both did use exxos PSU at when testing. USatan does however work on the H4 with IMP DMA chip.

STe 1 + HC (NO RESISTOR) had C398739-001A DMA chip = Did not work
STe 2 + HC + RESISTOR + IMP DMA = Did not work
STe 2 + HC + RESISTOR + -38 DMA = Did not work
H4 + IMP DMA = Does work

The C398739-001A should work. I think you have some other problem going on, maybe a bad DB19 connector or something like blown buffer chips or something.

I saw your wanted thread. But if you already have a C398739-001A DMA then DMA chip its likely not the problem. Your done all the mods I think now. Can you format a floppy without errors ?

Do you have a bog standard 1040 ST of some sort, so not H4, not STE, that you can try it on?

If not, and you're willing (I'm assuming you're in the UK) to cover the cost of postage I would be willing to test the US on my machines.

I have ST/F/M/Es, Megas, an H4 and Mega STE I could test on, and it would at least prove the US one way or the other.

Entirely up to you, but the offer is there.

Also, which driver are you using again?

Sadly the C398 chip is soldered on my brothers atari ste so i havent tested it in my ste. Atm i dont have a "proper" chip to put in the STE other than the original IMP one.

exxos wrote: 17 Jul 2022 13:45 The C398739-001A should work. I think you have some other problem going on, maybe a bad DB19 connector or something like blown buffer chips or something.

I saw your wanted thread. But if you already have a C398739-001A DMA then DMA chip its likely not the problem. Your done all the mods I think now. Can you format a floppy without errors ?