Need UM6845B IC

S

Scott Parsons

Guest
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
 
You should be able to get it from RS Components or Farnell


"Scott Parsons" <sparsons@_REMOVE_iinet.net.au> wrote in message
news:sparsons-1608030858300001@192.168.0.9...
: 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
 
This link may help

http://www.questlink.com/prodBrief.jhtml?type=brief&param=61332&compid=11371&compName=Mentor%20Graphics%20Corporation=&partNum=M6845

Eric wrote:

You should be able to get it from RS Components or Farnell


"Scott Parsons" <sparsons@_REMOVE_iinet.net.au> wrote in message
news:sparsons-1608030858300001@192.168.0.9...
: 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
 
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

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