Star Tech Journal

STAR* TECH Journal
December 1991
8(1
Randy Terry
Alpine Amusement
Connersville
Indiana
Wells Gardner 4900
Vertical Height, Vertical
Collapse & Sync Problems
Wms/Bally
Pin Lamps
&
Solenoids
SUBJECT
SYMPrOMS
A few problems I've encountered with the Wells Gardner 4900 series
monitors (not covered in previous STAJUrTECH Journal articles).
• . .:-:-·.:-:·,·-:-:-:-_,·,··,_.·.:·-.-:-·-:-:-: ·._.·._-:-:-:-:-:::::::::::::::::::::::::::-::::::::-<<:,:::::::::::-.-.·.·
P1foBLEM
Vertical collapse{willappearas ii
fathotizontal line).
""""""'
....
,
•••····· >i )
. Be$t descriptiofrJcangi"V'epn. this
C>n.e: l\ionitor out of~y11c/ ••·•....... . ....... .
.....
. .... , ..
Sotmo:N' .•.· ·.· . .
. . · .
,
.·,·· -.-.- ... ·.··,·,·,·,·.·,·.·.·.········'
.
, .... , .
....
.
'
I>isp1El.yi.11g••·"squiggly"••·borizo.rital
. . .
:m~pla.ce C313(100u@l60v).···
lines across•the mopitorapproxi-
llla.tel;Y g inches.· in. height a(the
ce11tef·•of the··monitor.·••·••
One or more flasher lamps on
playfield or in back glass not
working. Bulb, wiring , driver
transistor and associated CPU
circuitry known good.
SOLUTION
On backbox interconnect board,
check continuity between J4 and
Jll and 12.
Chances are you will find one
open due to the fact that resistor
· Pn.0131.11:M .. < . • . •.
<
Sot.lJ'l'loN
Rl-12 ( depending on particular
• l.,a.ckofyerticalheight on top
.·Replace C301(330u @16v)ofin.- • flasher bulb) is open.
tjf xµonitofthatls tq<}bright with • spectPCB for coldsolderjoints ol"
broken.trace inthis area. <
NoTE
horizontal retrace lines;
When troubleshooting controlled
solenoids with same symptoms as
S61.tm<>N
. . . . . . . . . . . . . . . . . . . . . . . . . .
above, follow these procedures,
~pla.ce Q701{1000u @.215v-).
but you will usually find a cold
(burnt) solder joint on J4 & J5.
••••••••••••
,,.
'
·. -··· .. • .. · ··:•··.·•·:, .. ·.·.·····:·.·:· . . . . ··.·· .. ·.·.·.·.·.·.·.· .. · ....
i
half
·······
•••••••••
.
* * *
Atari Centipede Power Up Problem
. SYMPrOM
No power up. First and second
player Start switches are lit con-
tinuously. Regulator Audio 11
PCB and CPU known good.
PROBLEM
Cl (26,000u @ 15v) capacitor in
the power supply is open.
NoTE: Replace CRl (MDA 3501
Bridge Rectifier) also, even
though it will check fine. If you
don't, you will the second time you
change the cap!
~