Re-trying my chances with my 65xe

[somacast]

Hi,

 

I had sometime to spare mainly after investing alot of money in this same black screened arabic 65xe .. Ive got the troubleshooting manual thanks, and using its ICs logic probes guide i spent some hours and reached the following , the way i wrote down different logics is IC# (original supposed to be logic----> the logic i got)

 

CPU , Antic , GTAI , and something else I think all replaced, all rams are 100% good.

 

any suggested point to start here? thnx 

[somacast]

also noticed that a few tens of power cycles makes pin 17 of U3 gives Pulse instead of wrongly giving H, and similarly a few pins of U2 gets right as well .. with no effect on black screen other than the same dotting noise, no sound , no hope with holding option , same RF /AV .. etc

[Rybags]

Try a diag mode cart like Asteroids or Star Raiders.

Try an alternate OS (assuming socket is the same)

Does it black screen always?  Normally a reaonable proportion of powerups will be non black, sometimes even with a PM stripe or two, for just under a second then go black.

That indicates that at least the OS is getting a start.

[somacast]

thanks, however os chip is behaving 100% right along with basic chip as per the manual guide for pins logics readings, so its outta question for me , Antic is all missed out if you may refer to the photo of diagnosis results .. thnx

[xrbrevin]

might be worth checking the MMU as it plays a part in the OS-ROM being enabled on power-up

p.s. my neck aches..

Edited July 7 by xrbrevin

[somacast]

Thank you 

if you refer to the attached photo , I did actually check all the ICs with the logic prob against the booklet, and many have shown the written differences.. so my question was where to start among those .. i will c the mmu differences though .. 

[xrbrevin]

im not familiar with the Arabic XE, does it just have a different OS-ROM and character set?

attached is the literature i have for the XE. it is listed as 130XE but the difference is marginal and the data is valid.

 

130XE - Sams ComputerFacts.pdf 130xe Hardware Manual.pdf 130xe.zip