Atari 1040STF with TF536 20 bombs

[Astal]

Also yes I know it is on the TOS 1.62 setting, that was just a test to see if it would do anything at all. All testing previously was 2.06

[PhilC]

@Astal apologies, I had presumed it was a rev 2 you were using.

The rev 5 will boot to tos with a standard version of 2.06 but yes you really do need to use the patched version the exxos did. I'm having trouble with Emutos 1.2.1 myself at the moment with random crashes. Tos 1.62 will not work with a TF536 though.

Your soldering from the photos looks pretty good. So I would check to see if you have any loose pins on the CPLD, buffers and Ram chips. Also its quite common for flux and solder balls to breach the pins on the rom socket too, so you need to have a really good look at those. Ideally you need some kind of microscope to view the pins and specifically in between them for breaches between pins that you won't be able to see or check with a multimeter. `I'll try and give you an example of what I mean later on

[exxos]

I did not see it was a rev 5 in use. But indeed you need a known working CPU from the store and a TOS206 ROM from the store.

I've not read the whole thread but worth confirming that's what you have. Some people burn their own ROM which is fair enough. But "any old ROM" will likely cause CRC errors as they won't be fast enough.

[PhilC]

@Astal so here's an example of what you could see in between the pins of chips and the rom socket.

I've deliberately not cleaned it up yet, just so you can see the small solder balls that can cause havoc.

Screenshot 2022-09-04 at 15.50.47.png

[Astal]

@exxos Which part number for the TOS 2.06 ROM? Or what speed grade is needed? 50MHz?

@PhilC I'll go take a look again, and probe for any bridged pins.

[Astal]

@PhilC So three pins were bridged, I ended up removing the socket and they're bridged on the mainboard,

A17 is continuous with I can't remember which pin and CE and Vpp are connected.

A17 is continuous with the bank select left side when looking at it from the ROM/CPU side, which makes sense. I've noticed there's a TON of flux on the board however, I'm going to soak the board in alcohol tomorrow to try and remove it. I'm also going to be replacing the ROM socket with a new PLCC-44.

[PhilC]

@Astal ok cool, sounds like you are making some progress.

I hate those smt sockets, they are the part that cause me the most issues

[Astal]

@PhilC I will be testing a new emuTOS burned ROM and a patched ROM when they come

[PhilC]

@PhilC I will be testing a new emuTOS burned ROM and a patched ROM when they come

Ok cool, let us know how you get on

[Astal]

@PhilC Installed a new ROM socket and board has been soaked in alcohol and dried off, time to test it one more time with this ROM, I should have the programming adapter tomorrow or the day after.

Edit: Tested, it doesn't bomb anymore with the new socket and cleaned from flux, however it either white screens, gets to the Atari screen and hangs, or hits the Atari screen and puts some part of the CRC error on screen then hangs. The new socket is a good 3M one, and I checked all the pins and it's all good, so hopefully the ROM is the issue. I'll send Exxos a message since it's one of his fast TOS 1.62/2.06 ROMs that's the problem if that fixes it.