Need UM6845B IC

[Scott Parsons]

Hi All

I am trying to repair a wesmar sonar and have traced the probelem to the
CRT Controller IC UM6845B. The IC was not producing any sync pulses and
so the display was the usual mess. I found that some of the early Amstrad
computers (CPC464) had the same IC. I finally managed to get hold of an
Amstrad and dutiflully pulled the IC out (Motorola MC6845 in this one)
popped it in and ..... a perfectly synced BLACK screen(sync pulses present
on the chip, but video blanked). Further research suggests that the
Motorola and UMC versions may not be interchangeable....

So I am trying to find the UMC chip.

Can anyone help


Thanks
Scott

 

[Rod]

This link may help

http://www.questlink.com/prodBrief....me=Mentor Graphics Corporation=&partNum=M6845

 

[Scott Parsons]

Thanks to All for your help.

I managed to get hold of one and also found another associated chip on the
board was faulty.

Now it works like a "bought" one!

Regards

Scott