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GI fuse keeps blowing

RudeDogg1

RudeDogg1

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Joined
Dec 27, 2012
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8,515
Location
Barnstaple, Devon
Since receiving Congo this week I’ve thought the backbox looked abit dark but hadn’t had chance to check bulbs. So had a look just a min ago and there is a string out. Then I checked the fuses F113 had blown. So I replaced it and it blew again. Anyone know what would cause it to blow?
 
RudeDogg1 said:
Since receiving Congo this week I’ve thought the backbox looked abit dark but hadn’t had chance to check bulbs. So had a look just a min ago and there is a string out. Then I checked the fuses F113 had blown. So I replaced it and it blew again. Anyone know what would cause it to blow?
Click to expand...
Check each socket for a short

Sent from my D5833 using Tapatalk
 
If there seems to be a short-circuit on this string circuit, take out every bulb from the array, then power-up the machine with a fresh fuse at F 113. If it remains okay, one or more of those lamps is bad. If it blows, then a socket (or sockets) may be shorted, or there may indeed be a short on the circuit board. Check again with the connector detached to show if it's sockets/wiring or circuit board.

With Wpc 95, though, I don't think the backbox G.I. circuits have dimming 'triac' components, they're simple always-on circuits
 
Well I didn’t get very far I thought I’d try without the connector connected to the board and a new fuse first. It blows once it has booted
 
Ignore that for now just realised it was using a to low a fuse. Really struggling to read these tiny ones. So will be back on it once I source some
 
Ignore that for now, although I would still suggest a board issue, then shouldn't be any draw unless a component is faulty.
 
Ooh, that shows it's on the circuit board, then. If there's no load connected, even a low-rated fuse should hold.

I've just snatched a look at the manual, and apparently Wpc 95 uses diode pairs for the backbox G.I., four P600D (or maybe P6000) per circuit
 
Jay Walker said:
Ooh, that shows it's on the circuit board, then. If there's no load connected, even a low-rated fuse should hold.

I've just snatched a look at the manual, and apparently Wpc 95 uses diode pairs for the backbox G.I., four P600D (or maybe P6000) per circuit
Click to expand...

Where are they located I can’t see them on the component list for the power board?
 
Bottom left. But they may not be installed. If they are installed carry out the mod to remove them and replace with wire links. There’s no need for GI to be DC. It just leads to burnt circuit board.

Also bear in mind that they supply two connectors for playfield and backbox. You should check both connectors. A common fault is the most wiring of strings so that two strings are being fed by the same fuse across two connectors.
 
I remembered I had a few of them test fuses and just so happened to have a 4. So I plugged in and powered up the 3 connectors for the backbox lights one at a time and typical it’s not tripped and they are all working. Will check the PF connectors next hopefully I find nowt ha
 
While starting my investigation I’ve found 3 connectors not connected to anything and no other half to connect to. For things removed in production?

17038353eb353b808cc0d7653489203b.jpg

419f065aecb4f16b28a895eb4b223a26.jpg

Also thought I’d do an edge test to see if anything weird was going on. And there is sighs when u press the watching target trough switch 4 closes I’m assuming it’s not meant to?
 
The GI connectors look to be mis wired.

From left to right they should be the same on both connectors

White-violet
W-green
W-yellow
W-orange
W-brown
Violet
Green
Key
Yellow
Orange
Brown
 
How odd I connected it’s up the way you and the manual says and now a different string doesn’t light despite there being continuity. I’m tempted to just cone t it back how it was because I had em all working and just keep an eye on the fuse.

Also this is the switch issue I spotted earlier. Unless it’s meant to do this not sure what purpose that would serve tho?

 
You most likely have a miswired switch / diode on that target.

One switch action should only ever produce one switch response.
 
GI. Wire it up correctly and then find out where the fault is.

Measure for ac voltage across the coloured pairs. Identify which colour is missing. Then leaving one lead on one of the errant pair, move the probe to another output. Then repeat for the other wire of the pair. Then you know which of the output pins is at fault. Then trace that pin back with your probe.

Double check all the fuses.
Reseat the short ribbon cable.
 
Not sure what the hell im doing wrong (I’m **** when it comes to using a meter to fault find) but I’m getting voltage on every pin
 
So now measure at one of the non working lamp sockets. It is possible that all the lamps in the string are blown. If you don’t have power then trace the wiring back towards the connector until you come across the break
 
pinballmania said:
So now measure at one of the non working lamp sockets. It is possible that all the lamps in the string are blown. If you don’t have power then trace the wiring back towards the connector until you come across the break
Click to expand...

Tested all bulbs in the non working chain and has continuity from the end way back to the board. It worked when it was wired wrongly with the test fuse on so I know there’s no break.
 
You say you have volts at all pins. ignore continuity. Do you have volts at any sockets. If you don’t then you have a break in continuity. If you do then your lamps are blown or the sockets are bad.

Using meter in continuity can give false results when lamps are installed and connected to pcb.
 
RudeDogg1 said:
Not sure what the hell im doing wrong (I’m **** when it comes to using a meter to fault find) but I’m getting voltage on every pin
Click to expand...

Where is your ground lead? You should have both leads on the connector across same colour pairs initially, then when errant output is found move one probe to another output to decide which pin is not working.
 
Now I’m confused I don’t think I was doing it right but now I can’t remember how I did it and not sure how you mean [emoji53]
 
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