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STAR*TECH Journal
August 1993
W-8
8-LINE BOARD
VIDEO GARBAGE&
IMAGE PROBLEMS
All ••mohitor Clrticles <
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1993 publishediinO
•··handy easy-to:.read .••
format.··.
• ov~r 2s•••naw••vic:reo
······m•o•nita•r·•·•svrn•pto•ms
and·Fixes in each.
• Thesetips previ-
c>usly ()ppearecfln
>srAR*T£CHJodr-
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bdl's Volume l l,] 2,
> 13 orT4. Upddfe
your tecfihlcar·
library with ffiese
Valu
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Kenneth R. Duncan
Monitor Exchange
Millington, Tennessee
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ORIGINAL SYMPTOM
SOLUTION
Screen full of red "O". Battery
measured less than 1 volt de.
Replaced the two diodes in the
+5/battery switcher circuit .
Screen came up with the cor-
rect attract mode image. Volt-
ages were now 4.2 V de with
power on and 3.86 Vdc with
power off.
ORIGINAL ACTION
Replaced battery.
SECONDARY SYMPTOM
Screen came up with a partial
image with wide vertical lines
and "garbage".
SECONDARY ACTION
Measured voltages at pin 24 of
the 64k RAMs at Jl/L 1. Found
2.17 volts de with power on and
3.86 volts with power off.
p ARTS/LOCATION
The original diodes are~
1S1588. We subbed 1N4148
diodes. The PCB is still work-
ing properly after 2 months of
field service. These diodes are
located next to the "Reset"
switch .
..... .
references.
/81..Js.,.-·•··.·.... DC,
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• add$3.50s/h
·.· ·•·.Qrder <.•.•.•··
PrepaidorCtJo<
S*TJ ••••
·po Box 106S
Merchantville, NJ
08109. 609/662-1080.
Mod's, Fixes & Technical Tips
Gather Dust In Your Service Files...
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