Atari 1040STF with TF536 20 bombs

[Astal]

Hello! I recently installed a TF536 in my 1040STF, I don't see anything bridged and I don't see anything funky with continuity, it does one of 4 things, seemingly randomly

Boots up to a white screen
Boots up to the white screen with Atari logo, about to do tests, and hangs
Boots up to white screen with Atari logo, gives CRC error and hangs
Boots up to white screen with Atari logo and gives 20 bombs

I have not applied the fixes yet, I'm assuming this is something that could be related to that? If anyone has any ideas, please let me know! Thanks everyone.

Edit: it has been recapped, PSU and mainboard. The system worked well with the 68000

[stephen_usher]

It would help to know what board revision the motherboard is.

However, sounds like the symptoms I had at one point. It turned out to be mostly poor contacts on the MMU socket, plus slightly poor contact on the CPU socket. The TF536 isn't as tolerant of bus noise as the 68000 is.

[Astal]

I'll try some contact cleaner and see, it's a strange revision I haven't seen anywhere else, I want to say it's C103225.

To get the TF536 to fit I had to remove the shielding over the shifter and the brackets on the PLCC sockets.

[Astal]

Removed and cleaned sockets, reseated everything, no avail.

I am using an RC50 I got off eBay, so could that be the issue? Remarked CPUs causing problems... Not the first time.

[PhilC]

@Astal yes the cpu could very well be the issue, same for soldering issues and for the header pins on the tf536. I’ve had loads of issues with them making poor contact.

[Astal]

I'll check the pins, I'm betting it's the CPU. When I get some cash in I'll probably buy a tested one from exxos and see.

[Astal]

@PhilC I got a new 030, it is doing the same thing, I looked again and like an idiot I don't have the ACSI0 pin hooked up on the board, I think that might be causing the issue, it hits ASCI init and hangs/dies maybe. Where does that hook up on the board? I looked through the TF536 pages and couldn't find it.

Edit: I'm dumb, I think I figured it out, I'm using a fast dual-TOS ROM and not the patched 2.06...

[DoG]

I find EmuTOS is much kinder/easier to get into desktop if you got mods on main board.

[PhilC]

@Astal it won’t be the asci cable which you connect near the asci port but can’t remember off the top of my head.

20 bombs is usually cpu related or a bad connnection either due to soldering or the header pins not making a good connection. The header pins are a real pain. On an A500 I had to lever them up slightly on one side till they worked.

Take some high res pics of your soldering, zip them and post on here and I’ll see if I can see anything causing an issue.

[Astal]

@PhilC Ok, got the pictures, three pins broke off when I was removing it from the socket, so I removed them, ignore that, I'll repair that. Pictures attached in ZIP file, I tested continuity and didn't see any issues with bridged chips, I had someone else assemble this one because I was feeling lazy :lol:

The thing standing out to me is the non-patched TOS ROM, I have two new 27C4096s coming to flash with emuTOS and the patched TOS 2.06. If the patched TOS fixes it, I will try to boot the 512K emuTOS image for kicks and giggles if no one has tested it.

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