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Paddle-Ball
arrived in the Repair Station completely dead. Since the TV in my
Fascination
Pong Cocktail is
also Hitachi I was somewhat familiar with the chassis.
I have still not been able to find a schematic for either
TV. However, as with any old TV, there always seem to be some
loose connections and bad solder joints. Once thse were repaired
I tried to power up the TV again. This time the I was met with
full raster but just a white screen. I connected the PCB but
unfortunately had the the exact same white screen.
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I shut off the game, disconnected the TV and removed the
back. A blown capacitor (220uf 16V) at location C714 was
immediately spotted. This was the identical capacitor that had
failed in the TV in my Fascination Pong Cocktail.
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Interesting enough the failure was exactly the same where the aluminum
can was blown completely off the chassis and the dielectric was
everywhere. I actually found th can in the bottom of the arcade
cabinet. Thankfully had the foresight to buy two capacitors
of this type when I was repairing my other TV so I had one readily at
hand. |
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I
replaced the blown capacitor with a brand new 220uf 32V capacitor. I believed the TV was now fixed so I reassembled it and
moved on to the PCB and arcade cabinet. Lucky enough the original wiring schematic was still on
the back door!
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I was able to confirm the voltage to the TV, coin mechs
and lights were correct. The voltage to the PCB was close (10.4VAC
instead of 9.5VAC). All of the chips on this PCB are 74XX chips
running on +5VDC but when checking them I found only 0.4VDC was making
it to them. This explains why the PCB did nothing. I confirmed 9.5VAC was making it past the edge connector
but the voltage on both
sides of the large blue capacitor was way off. The only thing in
between them were 4 diodes making up a bridge rectifier. All
checked good while on the board but my suspicion was that one or more
were bad. I removed all 4 and found that 2 of them were indeed
bad. All 4 diodes were replaced.
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The voltages to all the
chips on the PCB now tested a very smooth 4.95VDC. I plugged
everything in and was met with the 'attract screen!' The game was
completely disassmbled and cleaned both inside and out. New locks
were installed. Bring on the pong tournament!
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