Re: CBM Drive Mechanisms

From: Nicolas Welte (
Date: 1999-08-11 11:00:53

William Levak wrote:
> No connection on pins 1 and 2 would indicate a mechanical WP switch
> instead of a LED-photocell combination.

It's somewhat different. For the Chinon drive the WP LED is mounted on
the direct drive spindle motor PCB and gets its power from there. So the
supply from pins 1 and 2 of CN4 is not needed.

The term "MOTOR LED" is not quite correct. In the case of the 1541A and
B/C, it is the "ACTIVE LED". The spindle motor is controlled by an extra
three pin connector on these drives. In the 1541-II, the active and
power LEDs are connected directly via cables to the main PCB, there is
no connector. Pins 5,6,7 on CN4 go to the spindle motor control PCB.

In my 1541A/C drive (the one with the white case but 250442 board) pins
4,5,6 of CN6 are connected to the track 0 sensor. This is an integrated
light barrier with LED and sensor in one case. One is GND, one is the
LED supply and the other one is the sensor input. On most 250448 this is
tied to GND with a jumper, to make the use of sensor-less drives

> The fact that your 1541C has 9 lines on the connector indicates that it
> may actually be a 1541C drive and only the circuit board has been changed.

I can't be sure of that, I got it second hand. But since the original
owner had a parallel cable installed and also told me that he fried the
VIA while installing it, I don't think he ever had it in a repair shop
to get the complete board replaced.

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