Blitter Issues, 1040 STFM

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exxos
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Re: Blitter Issues, 1040 STFM

Post by exxos » Tue Jul 30, 2019 12:50 pm

Probably the thing to do is go around all the blitter pins with a scope and see if anything looks odd (the address bus will look like total crap anyway). Though there isn't much else it can be other than a bad solder somewhere. You should also check with a meter all the blitter pins you can which go back to the CPU & GLUE.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: Blitter Issues, 1040 STFM

Post by rubber_jonnie » Tue Jul 30, 2019 12:58 pm

Do you have access to a diag cart at all? I have one that runs the hardware tests and includes a blitter test which might get error codes relating to the problem.

One thing I have seen on these chips and their bretheren (Glue, MMU), is that it is possible for the pins to get twisted and to touch their neighbor on the chip, so it's worth flipping the blitter over on it's back and having a quick check.

It's also well worth checking that the pins are all clean (Socket and blitter), and in the case of the socket, are extended enough to make contact when in the socket.

Also, there is variance between sockets (I think exxos reported this) in that he divider between pins on the socket varied and caused problems with contact, so worth plugging in the chip and using a magnifying glass to check the socket isn't causing problems.
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Re: Blitter Issues, 1040 STFM

Post by exxos » Tue Jul 30, 2019 4:11 pm

Yeah there was a whole thread on PLCC sockets...

viewtopic.php?f=23&t=74


Generally 3M seem to be only good ones so far.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

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Re: Blitter Issues, 1040 STFM

Post by rubber_jonnie » Tue Jul 30, 2019 4:20 pm

exxos wrote:
Tue Jul 30, 2019 4:11 pm
Yeah there was a whole thread on PLCC sockets...

viewtopic.php?f=23&t=74


Generally 3M seem to be only good ones so far.
Ahh, that's the topic I was looking for!
Collector of old Atari things:
800XL + Ape Warp mod, 2x 1010 cassette, 1050 + Happy mod, 65XE (128k) & XC12, SIO2SD, 2600jr, 7800 and Lynx II
Atari 520ST (1Meg) + Gotek, 1040STFM + Vortex ATOnce + Gotek, 1040STF long button floppy, 4160 STE with Gotek and ROM switcher, 4160STE with 32Mhz booster, ROM switcher and CosmosEx, not to mention various bare ST boards for testing including a PAK 68/2 :)
Plus the rest..
Amiga stuff, Mac stuff, Sinclair stuff etc...
www.electronicnothingness.co.uk

Cimmerian
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Re: Blitter Issues, 1040 STFM

Post by Cimmerian » Tue Jul 30, 2019 5:33 pm

Thank you both I really appreciate it - This is very frustrating !
exxos wrote:
Tue Jul 30, 2019 12:50 pm
Probably the thing to do is go around all the blitter pins with a scope and see if anything looks odd (the address bus will look like total crap anyway). Though there isn't much else it can be other than a bad solder somewhere. You should also check with a meter all the blitter pins you can which go back to the CPU & GLUE.
I started this job today, as far as I can tell soldering of the socket seems good, there's no shorts between pins either.
Is there a (legible) schematic that includes the blitter anywhere to be found do you know? would be useful for this.
rubber_jonnie wrote:
Tue Jul 30, 2019 12:58 pm
Do you have access to a diag cart at all? I have one that runs the hardware tests and includes a blitter test which might get error codes relating to the problem.

One thing I have seen on these chips and their bretheren (Glue, MMU), is that it is possible for the pins to get twisted and to touch their neighbor on the chip, so it's worth flipping the blitter over on it's back and having a quick check.

It's also well worth checking that the pins are all clean (Socket and blitter), and in the case of the socket, are extended enough to make contact when in the socket.

Also, there is variance between sockets (I think exxos reported this) in that he divider between pins on the socket varied and caused problems with contact, so worth plugging in the chip and using a magnifying glass to check the socket isn't causing problems.
Alas I do not, and the blitter is nice and clean with no bent pins on the underside.
What I did do is attach a pin to the multimeter and test continuity between the top of each IC leg and the edge of the PLCC socket. Most were good , but some seems to need a little fettling before I got a beep. Could tie in with the evil PLCC socket theory.

Ill have another go at soldering the IC direct to the board. Another thing I've noticed is that the PCB is actually slightly warped in this area. Probably a manufactuing issue but its making my job a little harder.

Or Ill order a 3m socket and see if thats any better.

Thanks!!

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Re: Blitter Issues, 1040 STFM

Post by exxos » Tue Jul 30, 2019 5:38 pm

Cimmerian wrote:
Tue Jul 30, 2019 5:33 pm
Is there a (legible) schematic that includes the blitter anywhere to be found do you know? would be useful for this.
The 520ST schematic Is the best quality, but it does not include the blitter. But maybe you can use the remake schematic as its basically the same as the STF anyway.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: Blitter Issues, 1040 STFM

Post by Cimmerian » Tue Jul 30, 2019 9:00 pm

exxos wrote:
Tue Jul 30, 2019 5:38 pm
The 520ST schematic Is the best quality, but it does not include the blitter. But maybe you can use the remake schematic as its basically the same as the STF anyway.
wow thanks - nice work :)

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Re: Blitter Issues, 1040 STFM

Post by Cimmerian » Wed Jul 31, 2019 12:38 am

exxos wrote:
Tue Jul 30, 2019 5:38 pm
The 520ST schematic Is the best quality, but it does not include the blitter. But maybe you can use the remake schematic as its basically the same as the STF anyway.
My Blitter now works! :yay2:
Thanks Exxos - that Schematic turned up something interesting:
blitpads.jpg
blitpads.jpg (76.69 KiB) Viewed 383 times
(

Excuse the state of the pads here Ive had this thing on and off more times than a....
You may notice Pad 22 - it disintegrated when soldering it early on - luckily its not used. :?
Also I'm afraid Exxos' pacman sticker has not survived multiple blasts of hot air ...
)

Anyway Pin 29 is meant to go to BGACK on the CPU . You can see close to pin 29 what looks like a via actually doesn't go anywhere for some reason on this rev. board, it doesn't even go through to the other side. I noticed this earlier, but payed it no mind until I started using the schematic testing continuity signal to signal, unfortunately after I decided to ditch the PLCC socket and try soldering direct to the board again.

Added a bodge wire as so:
blitok.jpeg
blitok.jpeg (73.99 KiB) Viewed 383 times
and everything now works.
I'd be interested to understand why this is so, could it be they never really expected anyone to ever install a Blitter onto this Rev. ? Or perhaps service technicians had instruction to add this trace in should they ever have had to fit one.

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Re: Blitter Issues, 1040 STFM

Post by exxos » Wed Jul 31, 2019 12:52 am

Oh wow well done!

I will have a look tomorrow to see if I have the same revision board. I guess its possible the PCB on that revision is wrong.. But nobody has found that issue yet.. I'm sure people have fitted the blitter to that style board before, so maybe its one particular revision.., we need to look into that ...

:bravo:
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
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Re: Blitter Issues, 1040 STFM

Post by exxos » Wed Jul 31, 2019 9:36 am

This is a C103175 REV.1 It has the track and I checked back to the CPU...I sucked the holes to show where its going..

Can you post the bottom side of your board ?


IMG_4489.JPG
IMG_4489.JPG (352.18 KiB) Viewed 367 times

IMG_4491.JPG
IMG_4491.JPG (352.88 KiB) Viewed 367 times
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

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