Play Meter

on the printed circuit board close to the picture tube . It' s on the left and is labelled 73 VREG . (See Chassis Component Location - top view) . Take care while making this adjustment (which must be made with power on) that you don't short out any components on the board with the screwdriver . Simply turn the control slowly in one direction or the other until an exact 73-volt reading is obtained. Do not run the regulator through its range as you may damage the monitor. The rest of the adjustments must be made with one of the most precise measuring instruments known to man-the human eye. To keep the play appeal at a maximum, it's important that the display be clean and sharp. If the monitor screen is dirty or crooked or compressed at one end and stretched at the other, the play appeal will be reduced. A complete check and service operation can be performed in 10 to 15 minutes. Because of the high voltages involved with the picture tube (12,000 volts or more) tremendous static charges build up. One can often feel the hair on the arm bristle when near the picture tube. This static charge attracts a lot of dust and dirties the face of the monitor. I start by cleaning the C.R.T . A quick spray and a wipe and the picture al ready looks much better. The most commonly maladjusted controls are vertica1 size and vertical linearity. The result of this is .compression at the top or bottom of the picture. This results in a poor display with equally poor player attraction qualities. Adjustment is simply a matter of turning the control one way or the other until the lines of the screen (called raster lines) are equidistant at the top and bottom . If you can 't see the screen while adjusting from the back, use a mirror to help you see it . I've found that a metal Boy Scout heliograph works quite well because I can toss it in my tool box without fear of breakage . The vertical size of the display D6 ZENER Q12 VERT DRIVE D7 Q6 AFC HORIZ PHASE DJ OSC DET depends upon the game in which 1t is installed . For the most part, the picture should be completely contained by the C.R.T. (picture tube) , with a quarter to a half inch all-around that's not being scanned . This may vary however, and set up is largely a matter of personal taste . The same goes for brightness and contrast , although excessive con trast causes out-of-focus , blurred images and care should be taken to avoid the over-use of contrast. Lastly, give the monitor a good looking over. Look for loose wires, leaky capacitors, excessive accumulations of dust (which should be blown away) or any evidence of overheating. That's really about all there is to it! A few simple operations that will keep your monitor happy and healthy. Note : A very detailed and informative service manual is available from : Motorola Inc., Display Products Div ., Carol Stream , Illinois 60187 U.S.A. The cost is 80 cents . Ask for part number 68P65130A701. Q7 HORIZ ) QB PULSE HORIZ SHAPER DRIVE T1 HORIZ ORI VER R74 73V REG ADJ TO CRT PIN 3 G2 TO CRT PIN 2 G1 ----LJ HORIZ LIN 36 QJ VIDEO OUT ~ ... 35 L1 ,,--::-34-- H0 RI Z l "" 33 SET · - 32 9 - · TO CRT FIL PIN 8 R10 VIDEO BIAS GND t'. {ii J, ¥J. ·.S:iJ r-:-- 22 23 24 25 , ~~ 2:/,,,so•"; Ql lST VIDEO AMP 02 2ND VIDEO AMP Q5 SYNC SEP ~~T PIN 4 FOCUS ;i "'""~ .,, ; = 3