exxos's Atari, Amiga & retro forum

Here’s my problem:

1040STF, with known good PSU and working fine before. I attempted the 4Mb upgrade (solder-less type), but it didn’t work, so I wanted to go back to a working machine. After re-soldering new 68 Ohm resistors (tried the old ones as well, same) and putting Shifter in newly soldered socket, I now have a screen that I’ve attached. It’s solid, and the computer is otherwise working fine. RAM test passed, as shown as well.

The only other change from a known working state was installation of blitter socket, but I did not enable it yet. I am at a loss what to do next... Thanks for any help!

I'm frankly perplexed, because that screen looks like a RAM problem, and yet ram test passes fine... :shrug:

Have you tried the colour test on the diagnostic cartridge ? it is possible you have a bad data line on the shifter somewhere... Could possibly not be apparent on even colour test... But that is all I can think of trying currently..

Unfortunately I dont have a test cart, will have to get one soon...

I’m tempted to remove the shifter socket, clean the area up and just solder the shifter directly again, just to see if I can at least have it working like it was.

Definitely worth re-soldering the shifter pins, have you try just simply pushing down on the board to see the pattern changes ?

Worth buzzing out of the Shifter socket to the nearest vias, they can break invisibly with mechanical pressure.

I did try pressing around to see if the pattern changes, but it is a solid screen. I took the socket out, and one trace lifted... Fixed that, soldered the shifter directly in, and guess what - everything is working fine! I think I’m going to keep this one as is for now.

As a side note, I’m new to ST boards, but they seem to be very delicate :) You look at them wrong and they get mad. I have honed in my soldering skills over the years on C64 and Atari 8-bits, and they are like tanks compared to these. Anyway, lots to learn!

polbit wrote: 13 Aug 2020 21:59 I did try pressing around to see if the pattern changes, but it is a solid screen. I took the socket out, and one trace lifted... Fixed that, soldered the shifter directly in, and guess what - everything is working fine! I think I’m going to keep this one as is for now.

:bravo:

polbit wrote: 13 Aug 2020 21:59 As a side note, I’m new to ST boards, but they seem to be very delicate :) You look at them wrong and they get mad.

Yeah, everyone here will say how fragile they are (mostly me in many many rants about it over the years) H4 time ;)

polbit wrote: 13 Aug 2020 21:59 As a side note, I’m new to ST boards, but they seem to be very delicate :) You look at them wrong and they get mad. I have honed in my soldering skills over the years on C64 and Atari 8-bits, and they are like tanks compared to these. Anyway, lots to learn!

You've just encountered one of the biggest drivers for @exxos and the others to develop the H4 & work on the H5...simply because they end up spending more time fixing the existing boards than they do on developing the next upgrade/add-on!

So, when the H4 is stable (and much easier to diagnose & fix if it does break), there is more time for them to invest in designing & making our next must-have upgrades!

I'm taking a similar approach but from the standpoint of a nice stable (and upgradeable) H4 meaning that I can spend more of my precious free time using it for music rather than fixing it.
If I want to spend all my time tinkering with the system then I'll go back to Windows & the 'joy' of every update potentially breaking my PC!

EDIT: As always, @exxos gets the point across in far fewer words... :lol: :roll:

Having a bad evening...keep clicking on quote rather than edit...can some kind moderator sort out the mess please!

I'll punish myself with an early night
:smackbum: :stars: :chairsmack:

Well done on the fix. You'll get used to doing them.

Take my Mega ST for example, i fix one bit and another breaks. :headbang: