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From: Juhani Jaakola on 18 Mar 2010 08:30
After been several years in my attic my 1541 drive is failing: when I
power up the drive (without computer connection) the green and red
LEDs stay on and the motor keeps on spinning.

I have read http://personalpages.tds.net/~rcarlsen/cbm/fix1541.txt by
Ray Carlsen.

I have checked that my 1541 has correct 5V and 12V voltages on diodes
CR2 and CR4.

And I have checked that when I remove the ROM (901229-05) I can read
its contents with GQ-4X True USB Universal Programmer, and its
contents match exactly the image file that I have downloaded from
http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/new/1541/

Anyway, I have ordered a new 901229-05 ROM and I'll try that when I
receive it.

I have removed every IC that is mounted on a socket and re-mounted it
again in order to correct any bad contact. But the symptoms remain the
same!

Please suggest me what I should try next!

Regards, JJ
From: Bill Garber on 18 Mar 2010 12:01

"Juhani Jaakola" <juhani.jaakola(a)kolumbus.fi> wrote in message
news:6a343a56-ac5a-4072-92cc-42dcf24acb2a(a)q21g2000yqm.googlegroups.com...
> After been several years in my attic my 1541 drive is failing:
> when I power up the drive (without computer connection) the green
> and red LEDs stay on and the motor keeps on spinning.
>
> I have read http://personalpages.tds.net/~rcarlsen/cbm/fix1541.txt
> by Ray Carlsen.
>
> I have checked that my 1541 has correct 5V and 12V voltages on
> diodes CR2 and CR4.
>
> And I have checked that when I remove the ROM (901229-05) I can
> read its contents with GQ-4X True USB Universal Programmer, and
> its contents match exactly the image file that I have downloaded
> from http://www.zimmers.net/anonftp/pub/cbm/firmware/drives/new/1541/
>
> Anyway, I have ordered a new 901229-05 ROM and I'll try that
> when I receive it.
>
> I have removed every IC that is mounted on a socket and re-mounted
> it again in order to correct any bad contact. But the symptoms remain
> the same!
>
> Please suggest me what I should try next!
>
> Regards, JJ

In an earlier thread, it was suggested that you swap out the 6502 with
a known good one. So far there is no evidence that you have tried this,
so, I suggest that you do so before persuing the issue any further.

Bill



From: Sam on 18 Mar 2010 16:44
I had the same symtoms whit my 1541. But it is normal that the green
led stays on.. :-)

The red led stays on and the motor runs continously. After swapping
the DOS rom UB4, the 6502 MPU and the 6522 VIA at UC2 with known good
ones I got no result. After that I unsoldered UA1 (74LS14) and UD2
(7407), who also been known to cause this symthoms, placed sockets and
found out that UA1 was bad. I repaired a lot of 1541's and a bad logic
chip is rare. Mostly the VIA (6522) at UC2 is bad. If you don't have a
spare 6522 you can try to swap the both VIA's at UC2 and UC3. When UC3
is bad the drive powers up and resets nomally but the screen indicates
"Searching for......" when a load is attempted and no motor runs and
the red led doesn't light.

Greetings, SAM
From: Sam on 18 Mar 2010 16:54
I had the same symtoms with my 1541. But it is normal that the green
led stays on.. :-)

And I'm sure your 901229-05 ROM is allright.

I had the same symptoms with a 1541:

The red led stays on and the motor runs continously. After swapping
the DOS rom UB4, the 6502 MPU and the 6522 VIA at UC2 with known good
ones I got no result. After that I unsoldered UA1 (74LS14) and UD2
(7407), who also been known to cause this symptoms, placed sockets and
new chips and found out that UA1 was bad. I repaired a lot of 1541's
and a bad logic chip is rare in my experience.

Mostly the VIA (6522) at UC2 is bad. If you don't have a spare 6522
you can try to swap the both VIA's at UC2 and UC3. When UC3 is bad the
drive powers up and resets normally. The screen indicates "Searching
for......" when a load is attempted but no motor runs and the red led
doesn't light.


Greetings, SAM
From: JPPBM on 20 Mar 2010 00:08
On Mar 18, 8:30 am, Juhani Jaakola <juhani.jaak...(a)kolumbus.fi> wrote:
> After been several years in my attic my 1541 drive is failing: when I
> power up the drive (without computer connection) the green and red
> LEDs stay on and the motor keeps on spinning.
>
> I have readhttp://personalpages.tds.net/~rcarlsen/cbm/fix1541.txtby
> Ray Carlsen.
>
> I have checked that my 1541 has correct 5V and 12V voltages on diodes
> CR2 and CR4.
>
> And I have checked that when I remove the ROM (901229-05) I can read
> its contents with GQ-4X True USB Universal Programmer, and its
> contents match exactly the image file that I have downloaded fromhttp://www.zimmers.net/anonftp/pub/cbm/firmware/drives/new/1541/
>
> Anyway, I have ordered a new 901229-05 ROM and I'll try that when I
> receive it.
>
> I have removed every IC that is mounted on a socket and re-mounted it
> again in order to correct any bad contact. But the symptoms remain the
> same!
>
> Please suggest me what I should try next!
>
> Regards, JJ

Red Light staying "on", and drive constantly spinning is The +12V you
have checked, Then 6502 , followed by Supporting Logic Gates &
Array....(As was found by another member with this problem....)
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