Tech Tips - Vectorbeam/Cinematronics monitor

A couple of quick notes:

First - *Safety Check*:

*These monitors do NOT have any X-Ray protection circuitry* so it is
very important that you verify the +/- 18 volt regulators are working by
checking for +18VDC at L1 and -18VDC at R87 or C32. When either
regulator fails the voltage goes from approx 18KV to 24KV, if both fail
the HV could go as high as 30KV. So it is rather important to check this
out...

Second - common problems:

A) Popping breakers. We are assuming here that you have diode checked
all the diodes and transistors including the short circuit protection
transistors Q9, 12, 2 & 11 and none are shorted.

1) Unplug yoke (removes load from output transistors), power up, and
check the voltage @ the emitters of Q17 and Q13 - this voltage must be
very close to +0.6VDC. If off then replace all three 2N5210s (cheap and
quick fix) as it isn't worth the time to figure out which one has failed.

2) If emitter voltages are good then check collector of Q8(Q3) - should
be close to 0.8VDC, and the voltage at the collector of Q7(Q4) should be
approx -1.3VDC. If the voltage of Q7(Q4) is not within 0.6VDC of the
voltage at Q8's(Q3) collector, then replace diodes CR15 - CR17 (CR4 -
CR6) and try again.

B) Missing voltages from HV transformer - check (be gentle here the
wires are fragile!) all the very fine wires for breaks at the solder tie
pins. If broken then burn off the insulation with a lighter, and add a
small extension wire to the pin then solder the cleaned fine wires to
this. Leave a bit of flex room for the wires by have a small bend in the
fine wires to avoid future breakage.

Hope this helps someone, these are problems I found with two monitors I
just fixed and the Vectorbeam monitor book
(Vectorbeam_Cinematronics_Monitor_cine_faq_v096.PDF) needs to be updated
some day...

John :-#)#

-- 
John's Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 
Call (604)872-5757 or Fax 872-2010 (Pinballs, Jukes, VideoGames)
                 www.flippers.com 
"Old pinballers never die, they just flip out"
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