Strange Behavior of 600XL

[+Larry]

Short story long...

 

I have a 600XL that worked perfectly with everything that I've tried when it had a 512KB sram expansion in it, along with a 32-in-1 OS module. Not willing to accept success, I put an Ultimate 1MB in it in place of the other mods, mostly because the 32-in-1 is difficult to update with new MyBios rom changes. Now, the U1MB appears to work great again *except* that something strange is going on with the cartridge port. It has difficulty reading a CF card in the MyIDE-II. Specifically, it can't read the FAT32 folder, nor can it read the partition table in the cartridge. It will boot, but has to retry several times. The Ultimate is good in other machines. This is a Candle V2, but I've substituted a Lotharek with the same result. The MyIDE-II works fine in all my other XL/XE computers. I've tried several CF cards, both fast and slow, but still the same error.

 

I'll try swapping chips, but I doubt that is a part of this. Does anyone have suggestions as to where to look?

 

Thanks,

Larry

[+Roydea6]

The only thing I ever tried for this symptom is to put the CF card into a PC and reformat Fat32 and put all the MyIDE contents back then put MyIDE ][ into a stock Atari and re flash the 512K rom CONTROL+F,

I didn't lose and partitions and it seems work again. I've only done this once though so not a tried and true fix.

[flashjazzcat]

Clock timing might be knocked out of kilter. Try replacing 74LS08 and/or the CPU and see if your results differ.

[+Larry]

CF had no effect.

 

CPU had no effect. But when I swapped out the 74LS08, it started working perfectly! You and Bob1200XL both mentioned the '08, so you both share the prize...

 

Can you expand a bit as to how/why you zero'd in on the 74LS08?

 

Incidently, the prize is 15 minutes of my eternal gratitude! But seriously, thanks a bunch!

 

-Larry

[flashjazzcat]

Nothing more than hard earned experience in my case Larry.