Service manual

H/Z-100 Service Bulletins
To configure the Winchester disk drive, select the proper hardware unit and refer to
the table below:
Hardware Unit Number
Pin Pair: 1 2
1-16 Open Open
2-15 Short Short
3-14 Factory Set
4-13 Factory Set
5-12 Open Open
6-11 Open Open
7-10 Open Short
8-9 Short Open
Pin pairs 3-14 and 4-13 are set at the factory and the programming plug is properly
configured for the drive in which it is installed. However, if you move programming
plugs from drive to drive, there is a chance that the drive will not operate properly
due to improper configuration of these pins. If you must replace a programming plug
on a drive, refer to the chart below for proper configuration of pin pairs 3-14 and 4-
13.
To use the chart, you must have the phase code of the disk drive. This is located on
a label on the disk drive case.
Phase Code
Pin Pair: C D E F
3-14 Open Open Short Short
4-13 Open Short Open Short
FSB-Z100-033: New Drive Shields
Later production runs of the Z-110 Low-Profile series computers used different
shields to provide greater vertical clearance for easier assembly.
FSB-Z100-034: Z-120 Display Brightness
The HE 57-27 diode used at CR-107 on the video monitor boards of the Z-120 All-In-
One model caused the brightness to change with temperature. This was especially
noticeable in background raster brightness.
To correct this problem, replace the HE 57-27 diode at CR-107 with diode HE 234-
353. This diode is faster and less sensitive to temperature variation.
Replacement of an HE 57-27 with an HE 234-353 at CR-107 will shift the power
supply voltage more negative and will require readjustment of both R-139 "Brite"
and R-148 "Focus" controls.
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