zChrises 520 STfm + TF536 project.

[zChris]

Hello all,

Thought id make a single topic about this issue. My current status is as follow:

I have a motherboard C070789 with GOEX, DualTOS, Decoderboard. I have done the st bus resistor changes and the 1772 pull modification ( https://www.exxosforum.co.uk/forum/viewt ... =17&t=1585 ). Have also disabled the cache on TF536. For my solder i have used leadfree solder.

With DualTOS + Decoderboard + Original CPU everything seems to run fine. I get into tos at both 1.04 and 2.06.

With TF536 the progress varies. Most of the time i see the Atari Logo and "Memory check Aborted". But once or twice i have gotten a busybee and a dialogue window that says "Failed too" and the rest of the message is not shown.

So do any one have any suggestion on what to do next? Im thinking on resoldering the CPU socket with leaded soldering and see if its some bad connection thats not easily detected with measuring ohm.

best regards zChris

[exxos]

What PSU are you using ?

[zChris]

Im using the standard psu that i have recapped.

/zChris

[zChris]

Just found out that leaded solder is not available in Sweden so i cant resolder it with leaded solder. But i think i will work over the points again with the iron.

/zChris

[exxos]

Trouble is with original machines is they are very temperamental when upgrading them.every machine has its own quirks and difficult to diagnose,

What is odd is the TF536 runs at 8mhz when booting and your not working even at that, you could try what I did but it was on a H4 https://www.exxosforum.co.uk/forum/viewt ... =10#p44169

[zChris]

I started the computer on my lunchbreak and it got so far as this:

V3gkpYJ.png

But after a reset it only got this far

LJKGf9r.png

If that gives any clues?

What does that mod do @exxos?

[zChris]

Also, everytime it freezes the LED on the floppy lights up.

/zChris

[stephen_usher]

That'll be bad memory access, possibly address line issue.

Check your TF536's solder joints and check for shorts on the Xilinx chip.

[PhilC]

That'll be bad memory access, possibly address line issue.

CHeck your TF536's solder joints and check for shorts on the Xilinx chip.

It's one I built, so should be good. If anything I would recommend upgrading it to the latest firmware @zChris as this mDe things alot more stable for me

[derkom]

Just found out that leaded solder is not available in Sweden so i cant resolder it with leaded solder. But i think i will work over the points again with the iron.

FWIW, I've done plenty of work on these old machines with no-lead solder (we also cannot get leaded solder around here) and the only solder-related problems I've had have been due to my incompetence, not due to the solder composition. Leaded may be preferable to some people, but it's by no means a requirement. I would be surprised if your solder composition is the cause of your problems.