Service manual

Wells-Garnder Color Vector Monitor Guide
Page 45 of 73
COLOR X-Y DISPLAY 92-053
INSTALLATION INSTRUCTIONS
INPUT PROTECTION CIRCUIT PCB
A038088-01
1. Remove R600, R605, R700 and R706.
2. Remove solder from all nine holes indicated in figure 13 [figure not included].
3. Straighten pins of PCB so that they are perpendicular to the board [meaningless to you
since you probably do not have the board].
4. Match and insert the numbered holes in figure 13 with the numbered pins in figure 1
[figures not included].
5. Solder.
All descriptions refer to a deflection board oriented component side up with the board label
"P314" at the top (right-side-up) and the two large electrolytic capacitors at the bottom. This
orientation will have the electrolytic capacitors "side by side" and the board will be "taller" than
it is "wide".
• J1 is R700's old top pin.
• J2 is R700's old bottom pin.
• J3 is R600's old top pin.
• J4 is R600's old bottom pin.
• J5 is the first "empty"/unused hole to the right of C701.
• J6 is the first "empty"/unused hole to the right of Q701 and below C701.
• J7 is the first "empty"/unused hole to the left of C602 and below D601.
• J8 is R606's old left pin.
• J9 is R706's old left pin.
SPECIAL NOTE: According to the Major Havoc manual, this Input Protection board came in 2
versions. Later versions had a 1K-Ohm, +/-5%, 1/4 W resistor as one of the "stilts" on the board
instead of a plain piece of wire. If your board does not have this resistor, here is what you need to
do.
• Locate the "stilt" wire connected to resistor R1 (22K ohm) and the collectors of
transistors Q1 and Q3 (type 2N3904) on the Input Protection Circuit PCB (the other end
is connected to the P314 Deflection PCB).
• Use a wire cutter to cut the wire, located in step 1, halfway between the two PCBs.
• Use a soldering iron to solder a 1K-Ohm, +/-5%, 1/4 W resistor between the two ends of
the wire cut in step 2.