A2K rev.6.2 mobo black screen

pietro_tiberi

Member
Joined
Sep 16, 2009
Posts
96
Country
Rome - Italy
Region
Lazio
Hi,

I'm trying to restore an A2k. CPU and Kickstart are ok (pulled from a working A2K). PSU is Atx and jumper J300 is set properly (pin 2-3 connected). CPU voltage is 4.94 V (pin 14-16).

But I get BlackScreen...what should i check next?

Inviato dal mio Redmi Note 7 utilizzando Tapatalk
 
I have a motherboard with the same issue. It is common for the A2K motherboard to suffer battery damage, and for traces between CPU and Kickstart ROM to be damaged.
What is the condition of the board around the CPU and ROM chip?
 
Some tracks look like damaged but I tested them with a multimeter an connection is ok. I checked carefully pin 6&7 from CPU to Gary,FatAgnus,buster&co and they are ok.
I tested pin 2,3,4&5 from CPU to ROM and they are fine....
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Inviato dal mio Redmi Note 7 utilizzando Tapatalk
 
Hi,
Pay attention to CPU socket the contact in the red circle not appear so good, be carefull with this.

cpusocketA2000.jpg
 
Last edited:
Hello,

even contacts on ROM socket are green-blue, sign of acid attack! Another thing, with this issue, sometimes, multimeter do not tell the truth! You need to clean all the contacts (solder joints and via) and replace sockets.

Regards
Stefano
 
Connection fron pin1 CPU to Rom is ok. But I have RST pin18 always High. could you helpm me?

Inviato dal mio Redmi Note 7 utilizzando Tapatalk
 
Hello,

the right things to do is replace CPU and ROM socket.

Regards
Stefano
 
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