exxos's Atari, Amiga & retro forum

Globox wrote: 17 Sep 2020 18:07 But the top right led (for floppy i think?) not working, and still not working after going back to stock doesn't ring a bell to anyone?

Yeah, normally a RAM or ROM fault. You can tell if ROM is running or not because the diagnostic cartridge should theoretically boot... Or you can use a oscilloscope and checked the ROM chip enables to see if they are switching power up or not...

If the ROM chip enables are pulsing several times at power up, then the machine is at least attempting to boot, which generally indicates the machine has a RAM fault... And of course the floppy LED will not blink unless the operating system is running which of course needs working ROM and RAM.

OMG I feel so stupid now!
Didn't check for continuity on the shifter adapter before installing it onto the motherboard...
Now I did, and it seems like quite a bit of the connections aren't soldered well... :oops:
Used the the multimeter a few times to find out which pins, but measurements aren't consistent, I guess this is because touching them with the multimeter made some of them make/lose contact.
But these were the bad pins in the first measurement:
7, 13, 21, 22, 24, 25, 26, 35
But I don't know if this many connections were bad when I turned on the Atari...
I have no idea if this can cause damage to my Atari or not, but i suspect it can?
If so, how bad could the damage be?

I shouldn't think it would have caused damage .. Probably you are missing the 16mhz output from the shifter which would explain why you have no valid video output as the entire board won't have any clocks..

exxos wrote: 17 Sep 2020 21:49 I shouldn't think it would have caused damage .. Probably you are missing the 16mhz output from the shifter which would explain why you have no valid video output as the entire board won't have any clocks..

But does that also explain why it still doesn't work after I put it back to stock?
Plugged in the shifter back in the original socket so problem should be solved then, no?

Ah true.. You would have to check then clocks with a scope..

exxos wrote: 17 Sep 2020 22:05 Ah true.. You would have to check then clocks with a scope..

Don't have an oscilloscope :(
Why do i need to check them?
Is it a problem caused by the bad soldering on the shifter adapter after all then?

Do all the pins on the MMU and socket look ok? And have a look at the shifter socket, its possible due to age that the sprung connections are corroded or simply bent so that they don't make a good connection any longer.

Globox wrote: 17 Sep 2020 22:15 Don't have an oscilloscope :(
Why do i need to check them?

Because your machine is dead and you suspect a dead shifter ?

exxos wrote: 17 Sep 2020 22:29 Because your machine is dead and you suspect a dead shifter ?

Yeah like I said, my knowledge of electronics is way too low to attempt stuff like this, but at least it's a great learning experience!
Only hope I can get it fixed :p
So i guess there's no way to check for a dead shifter with a multimeter?

Globox wrote: 17 Sep 2020 22:43 So i guess there's no way to check for a dead shifter with a multimeter?

Nope. Like I suggested, @Steve is the one to send your machine to figure it out.