(Topic ID: 207122)

Low voltage on GI backbox.

By finalquest

6 years ago



Topic Stats

You

Linked Games

You're currently viewing posts by Pinsider wayout440.
Click here to go back to viewing the entire thread.

#2 6 years ago
Quoted from finalquest:

Hi guys. First post here.
I'm restoring a getaway pinball.
I have an odd situation.
The controlled 555 lamps are barely visible through the playfields inserts. Specially on the darker ones.
I tried cleaning the inserts in the bottom playfield, but there wasn't any improvement.
I dont know how I can measure that the right voltage is reaching the lamps. The controlled lamps are flashing, so my Mulimeter cant get a correct reading

Check your +18VDC source voltage for the controlled lamps first. TP8 on the power driver board.

Quoted from finalquest:

I have a voltage drop on the backbox GI. Without lamps I have a solid 6.8V. But as I add more lights to the circuit the voltage begins to drop. With all the lights I have 4.5V.
Can a Bad Triac cause this symptoms?
.

The triacs rarely fail, most likely something like poor connectors somewhere, an oxidized or cracking fuse clip or something along those lines causing a higher than normal resistance, as the circuit is loaded the GI supply can't quite deliver the current. The GI requires not only the voltage, but more importantly, good delivery of current. The PinWiki is loaded with some good info:
http://pinwiki.com/wiki/index.php?title=Williams_WPC#General_Lamp_Problems

#5 6 years ago

Check the schematics, TP8 is after some components including two filter caps. Use your meter in AC to measure ripple voltage at the TP8 test point.

Promoted items from the Pinside Marketplace
$ 8.50
Lighting - Led
Pinball Haus
Led

You're currently viewing posts by Pinsider wayout440.
Click here to go back to viewing the entire thread.

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


This page was printed from https://pinside.com/pinball/forum/topic/low-voltage-on-gi-backbox?tu=wayout440 and we tried optimising it for printing. Some page elements may have been deliberately hidden.

Scan the QR code on the left to jump to the URL this document was printed from.