Video Ram Error

[Eun]

Well, iknow this is an old topic, but..

I have an MVS-1 PCB card, who had a normal
00008000 5555 55ff video ram error.
I did repace both the CXK5814 to new TMM2018s.

But after i had done that, the Video Ram Error did still remain..!??

But this time did i get following code!

00008000 5555 555D,

Anyone who knows what the problem is?
Is it just a bad connection some where? or ???

I have no idea!!???

(>_<)


help

 

[Razoola]

Eun:
00008000 5555 555D,

Anyone who knows what the problem is?
Is it just a bad connection some where? or ???

Check the new chips are correctly in place, it looks like 2 pins could be shorting causing 2 bits to be set instead of 1.

Raz

 

[Eun]

Thanx, Raz

I did try to check the new chips so they where correctly in place, by controling all pins one by one, when powering up the bord again, i did get folloing video ram error..

00008000 0000 008C spock

I dont get this bord?

 

[Nightmare Tony]

your lower order RAM has some problems. For the first error of D instead of 5, the binary code shows it to be 1101 instead of 0101. That means data bit 4 is disconnected or a bad trace, so that is pin 15.

for the 8C, that would probably be an enable, 18,20,21 or 23 pins would be suspect...

 

[Eun]

Thanks Tony!

It did help me allot, I think I will get it to work from now on!

BRB