exxos's Atari, Amiga & retro forum

@CeRiAl Black with white border is typically an indication of bad ram, so yes the diagnostic cart will be very useful but I'd recommend you start looking at the soldering around the MMU and Simm socket etc.

Its difficult to know where to look until the carts run. I mean you could have a bad ROM connection causing TOS to crash. Or it could be bad RAM / connection.. or a bad solder joint on the GLUE or MMU.. could really be anything.

PhilC wrote: 08 Sep 2021 20:37 @CeRiAl Black with white border is typically an indication of bad ram, so yes the diagnostic cart will be very useful but I'd recommend you start looking at the soldering around the MMU and Simm socket etc.

Thank you for the hint!
I'm quite a noob in the Atari-ST world, coming from the the Amiga side, so I'm not familiar with Atari-ST error-screens and what they could mean (like this screen) ;)

Some other observations:
I noticed the bridge for "error click" was not set on the H5, so to be on the safe side I set the "default" bridge, but I don't think this is related to my problem.

Another thing is that I don't seem to get keyboard clicks any more - sadly I'm not sure if this changed after putting the resistor on the regulator or when I closed the "error click" bridge or if it happened at random.

I also learned now that the number of bombs have an actual meaning (could have guessed this before :hide: ) so I looked them up.
I have seen 2 bombs (most of the time), 20 bombs, and sometimes 3 bombs.

• 2 bombs seems to mean "Bus Error"

• 20 bombs mean "unassigned/reserved" according to my list

• 3 bombs mean "Address Error"

Also the screen with the bombs gets increasingly corrupted over time when I wait (colored patterns appear in the background and a "brrrrr" sound can be heard which gets increasingly louder with the screen corruption).

So after seeing the meaning of these codes, I also planned to recheck my connections on the MMU and planned to try different RAM-modules (I have quite a bunch of modules to try, also different brands) as the next debugging step.
After your hint I will also check the SIMM-socket.

I could also switch a few chips with chips from my working 1040STF, but sadly not the MMU and GLUE as these are also of the SMT kind there.
Damn, I really shouldn't have chosen the SMT path, I knew it will make things more complicated! :lol:

I feel I'm close to the solution, because as I can see it accessing the floppy (at least in one of 10 tries) and seeing the bombs means to that it does at least something, like executing code from the TOS, graphic output works, audio works (at least I heard the clicks before) and so on... :geek:

exxos wrote: 08 Sep 2021 21:06 Its difficult to know where to look until the carts run. I mean you could have a bad ROM connection causing TOS to crash. Or it could be bad RAM / connection.. or a bad solder joint on the GLUE or MMU.. could really be anything.

I'm already in your store for ordering the cartridge :lol:

@exxos: Should I also get a separate TOS206-decoder board, or can I salvage my booster for this?
Sorry if this a stupid question, I'm really just not sure if the software on the Atmel is different on the "decoder only" board and if the software on the booster only works with the CPU on top - or if there are other differences regarding components on the board... :hide:

CeRiAl wrote: 08 Sep 2021 21:32
@exxos: Should I also get a separate TOS206-decoder board, or can I salvage my booster for this?
Sorry if this a stupid question, I'm really just not sure if the software on the Atmel is different on the "decoder only" board and if the software on the booster only works with the CPU on top - or if there are other differences regarding components on the board... :hide:

You can use the booster for decoding TOS206 (without the DIP CPU installed etc)

exxos wrote: 08 Sep 2021 21:45

CeRiAl wrote: 08 Sep 2021 21:32
@exxos: Should I also get a separate TOS206-decoder board, or can I salvage my booster for this?
Sorry if this a stupid question, I'm really just not sure if the software on the Atmel is different on the "decoder only" board and if the software on the booster only works with the CPU on top - or if there are other differences regarding components on the board... :hide:

You can use the booster for decoding TOS206 (without the DIP CPU installed etc)

Great, thank you!

It's alive! :yay:

I have double checked again every pin of the MMU, GLUE and SIMM-slot for shorts, for cold solder joints - all was fine.
But when I checked the TOS-ROM, I noticed that some of the bottom pins didn't really had connections to the socket "pins". Removed it, replaced it, and also replaced the RAM-module with another one (single-sided instead of double sided) - and tadaa! The board booted! Ran GEMbench, ran YAART - all fine! 8-)

I'm also now able to read 1.44 MB floppies successfully, so that is great too!

Here are some photos:



And as usual, I have a few questions now: :P
What is the correct and best way to make the 1.44 floppy auto-detection work? Right now I have HD-sensing not connected (where should I connect it to on the floppy? directly to the sensor?), so it now exclusively reads 720kb or 1.44MB.

Second question is again related the my ROM-decoder/booster @exxos : :hide:
I have placed the booster (wo/CPU on top) in slot #1, connected the booster's CE-pin to the ROM-CE "jumper" (right pin), and opened the DualTOS selector jumper. Additionally I "made" the bridge on the booster for 8MHz-mode.

However, when I try to boot with either the ROM-CE-pin connected or the open DualTOS jumper I only get a gray screen, no boot, no other error. Did I miss something, or should it work already like this?
If not I need to check my connections on slot #1 and the booster/decoder itself.

Thank you guys for your support so far, I'm very happy that the machine works now, thanks to your hints and support!
:dualthumbup:

CeRiAl wrote: 10 Sep 2021 19:26 It's alive! :yay:

Well done!

:cheer: :girldance: :cheer: :girldance: :cheer: :girldance:

CeRiAl wrote: 10 Sep 2021 19:26 What is the correct and best way to make the 1.44 floppy auto-detection work? Right now I have HD-sensing not connected (where should I connect it to on the floppy? directly to the sensor?), so it now exclusively reads 720kb or 1.44MB.

Solder the HD wire on the drive like below, this is the MPF920 drive.

CeRiAl wrote: 10 Sep 2021 19:26 I have placed the booster (wo/CPU on top) in slot #1, connected the booster's CE-pin to the ROM-CE "jumper" (right pin), and opened the DualTOS selector jumper. Additionally I "made" the bridge on the booster for 8MHz-mode.

However, when I try to boot with either the ROM-CE-pin connected or the open DualTOS jumper I only get a gray screen, no boot, no other error. Did I miss something, or should it work already like this?
If not I need to check my connections on slot #1 and the booster/decoder itself.

I assume you have a bad connection on your slot1 somewhere. Connecting the wire as you've described is all you should need to do. Check the address lines, DTACK,AS.

@CeRiAl Congratulations on getting your H5 to work! I've still not had the time to find the issue with the floppy accesses on mine but maybe over the next few days...

CeRiAl wrote: 10 Sep 2021 19:26 It's alive! :yay:

Top work!

:bravo:

BW