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From: Juhani Jaakola on 9 Mar 2010 06:42
I tried my Commodore 1541 disk drive after it has been in my attic
unused for years. The green light and red light and the spindle motor
turn on when I power up without the computer connection. Shouldn't the
red light and motor turn off after two seconds? In my case they just
stay on!

The drive does not work when I connect it to computer. The red light
and motor just keep going...

I have read http://personalpages.tds.net/~rcarlsen/cbm/fix1541.txt by
Ray Carlsen. I have PCB # 1540050. I have measured that I have 5V and
12V on diodes CR2 and CR4. I have lifted ICs UB4, UC4 and UC2 up and
pushed them back down in order to fix any contact issues. I looked at
UA1 and UD2 and I can't see visually any damage.

Is there anything else I could do?
From: JPPBM on 10 Mar 2010 01:44
On Mar 9, 6:42 am, Juhani Jaakola <juhani.jaak...(a)kolumbus.fi> wrote:
> I tried my Commodore 1541 disk drive after it has been in my attic
> unused for years. The green light and red light and the spindle motor
> turn on when I power up without the computer connection. Shouldn't the
> red light and motor turn off after two seconds? In my case they just
> stay on!
>
> The drive does not work when I connect it to computer. The red light
> and motor just keep going...
>
> I have readhttp://personalpages.tds.net/~rcarlsen/cbm/fix1541.txtby
> Ray Carlsen. I have PCB # 1540050. I have measured that I have 5V and
> 12V on diodes CR2 and CR4. I have lifted ICs UB4, UC4 and UC2 up and
> pushed them back down in order to fix any contact issues. I looked at
> UA1 and UD2 and I can't see visually any damage.
>
> Is there anything else I could do?

For Drive motor running continuously & RED LED staying ON....Check you
have+12V & check the 6502 (Swap it out with a know working one from
another drive) One of these is the most likly cause... if not then
there are a few Logic gates that support that 6502 that may be sending
it the bad signal...
From: DMackey828 on 18 Mar 2010 13:59
On Tue, 9 Mar 2010 03:42:14 -0800 (PST), Juhani Jaakola
<juhani.jaakola(a)kolumbus.fi> wrote:

>I tried my Commodore 1541 disk drive after it has been in my attic
>unused for years. The green light and red light and the spindle motor
>turn on when I power up without the computer connection. Shouldn't the
>red light and motor turn off after two seconds? In my case they just
>stay on!
>
>The drive does not work when I connect it to computer. The red light
>and motor just keep going...
>
>I have read http://personalpages.tds.net/~rcarlsen/cbm/fix1541.txt by
>Ray Carlsen. I have PCB # 1540050. I have measured that I have 5V and
>12V on diodes CR2 and CR4. I have lifted ICs UB4, UC4 and UC2 up and
>pushed them back down in order to fix any contact issues. I looked at
>UA1 and UD2 and I can't see visually any damage.
>
>Is there anything else I could do?


I had the same problem on a 41' I picked up. It may also be one of the
CIA chips. Switch them around. There's 2 of them, if the problem goes
away, on of the chips is bad..
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