Has anyone experienced ramsey going goo-gaa?

[patrik]

Hi everyone!

I have a friends A4000 here which I have been trying to fix. For a long while, the trusty old A3640 cpucard was used in this machine without any problems until a while ago when he got himself an Apollo 4040 card. It was then the fun(?) stuff began... the machine refused to work with motherboard fastmem installed and if you had the machine turned on for a while and rebooted it, it would freeze after the reboot - no crash or anything just still as ice (with no motherboard fastmem installed). The funny thing is that if you just didnt reboot it, it would be running totally stable for as long as you pleased.

I told him I could give it a look and se if I could do anything about it.

I found out that if you ran the machine with the Apollo-card unpopulated only having fastmem on the motherboard the machine would boot and work for about 1 min until it started to go slower and slower and slower until it just stopped... letting a big fan blow over the board and motherboard from the powersupplyside of the A4000 (without drivebays) seemed to solve the problem. I have spent many hours looking for bad solders, resoldering parts of the Apollo and parts of the A4000 motherboard, cooling components selectively. I really thought it was the Apollo-card that was bad because the computer had worked so fine with the A3640 and focused mainly on that. At the end, after pulling my hair with the Apollo, I began focusing on the A4000 motherboard and found out that it was the ramsey-chip that was the bad guy. If it is cooled _A LOT_ it works perfectly with motherboard fastmem installed and there are no freezes at reboots (with or without motherboard fastmem installed). Though that much cooling isnt possible in the A4000 case so I resorted to a mounting heatsink on the ramsey-chip and attaching a little fan in the gap between the daugtherboard and the frontplate to blow air underneath the Apollo on the ramsey-chip. With this fix motherboard fastmem cant be installed (If you for example use bustest and test the speed of the motherboard fastmem the system will become slow or freeze) , but if no motherboard fastmem is installed the system works fine and always reboots - no freezing or anything. That is very good as now the machine is usable again (ponder the inconvenience it is, not being able to reboot the machine ), the only backside is that motherboard fastmem cant be installed.

Now I am curious if anyone else has had any problems with the ramsey-chip?


/Patrik

[patrik]

@Castellen:

Yes this is indeed not a good solution, as you say the ramsey is probably prone to become worse. But if it works a year it is a extra year of A4000 usage for my friend .

The ramsey in this machine is indeed revision 7 (-07 is printed on the chip) . I have never tried surface soldering a PLCC, but I have done some various other surface soldering and think I am skilled enough to solder a new ramsey to the motherboard , alternatively a socket. Though removing the faulty ramsey from the motherboard would be much more difficult than attaching it or a socket (atleast this is my impression) . Do you have any tips regarding how to do PLCC desoldering?


/Patrik

[patrik]

Was also wondering if the Apollo-card could be generating signals of less quality than the A3640-card and thus making the ramsey misbehave easier.

Has anyone experienced an Apollo-card making their systems unstable?


/Patrik

[patrik]

@Wain:

That doesnt sound too healthy for the rest of the motherboard .


/Patrik