Bad Ram ?

[19Echo]

picked up a 65XE on craigs but when i powered it on it goes straight into the memory test. The second line of the Ram test it shows the 4th, 8th, 12, and 16th block as a dark color.

 

I'm guessing this isnt good. Pressing the reset button only has it going back into memory test mode.

Any idea which chip or chips are bad? Should i replace all of them? if so, what should i replace them with

 

thanks

[MEtalGuy66]

All of them.. ANd unless you are good at desoldering ICs, and have a temp controlled iron, you'll trash the board.

 

Go get 8 more of the same chips you got before (41256 or 4164) and 8 16pin sockets. Bring it over here and I'll replace them.. If you drop it off on a friday, you can pick it up sat evening, or sunday..

[Rybags]

The failed addresses should correspond to $4C00-4FFF, $5C00-5FFF, $6C00-6FFF, $7C00-7FFF.

 

On a standard 64K machine, every RAM chip is involved in any RAM access. PBI equipped 65XE has 2 x 4 bit chips, earlier one has 8 x 1 bit chips like the 800XL.

 

The XEs tend not to have any chips socketed (although one of my XEGS has a couple). The XE is also renowned for being easily damaged during solder/desolder operations.

 

That aside, a 2-chip machine will be much easier for you to remove the RAM chips and put sockets in.

 

It might be an idea if you have a Flashcart to flash a SALT image. Not sure if anyone's created an ATR to do so. You'd need the SALT image to be the startup image for the cart, in all likelihood it won't work from the standard AtariMax menu.

 

No idea though if SALT will do any better than Self-Test in identifying the problem.

 

It could well be just a memory select logic problem, but I suspect not because you'd expect the pattern to repeat evenly through all of RAM in that case.