Vector 4 - Page 186

SYMPTOM - CHECK
VECTOR 4
TECHNICAL INFORMATION
NORMAL 'ABNORMAL
2. CRT displays PROM
test, but system
will not boot,
Keyboard response
W - Winchester boot
F - Floppy boot .
| Replace keyboard if
character incorrect. If
system will still not
boot, replace SBC.
Drive Access
light (to see
if drive is being
accessed)
LED lights, drive
spins and steps
access head
Check voltage to
drive, ribbon cables
for proper connection
VCO on disk con
troller:
Floppy U1l-7
Hard disk Ul-10
See Page III 1-1.
500 kHz
10 mHz
Install new disk con-
troller and rebo‘ot.
If system will still not
boot, continue,
If out of tolerance,
Adjust VCO. If not
adjustable, replace disk
controller.
If signal is 0, replace
disk controller.
Disk controller:
if only one drive will
boot, install new disk
controller.
2-Floppy system:
switch jumper
blocks between
floppy drives.
Both drives boot from
new controller
Drive will not
boot: replace drive.
One drive still will
not boot: replace drive,
Problem follows
jumper block:
replace disk con-
troller
3. No serial peri-
pherals work
(keyboard, modem,
printer
2 MCLK
U112-4
2MHz square wave
(pulsating)
Isolate to faulty
component in clock
cireuit (U112, Y2, etc.)
09-01-82
7200-0001
VvV 3-3