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EBD - Intermittent fuse blowing

Widnesbernie

Widnesbernie

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Joined
Mar 14, 2021
Messages
165
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Widnes,Cheshire
Hello All,

Bought my 1st machine a couple of weeks ago.

Its an Eight Ball Deluxe LE, it was ok for the 1st week, but has now started to blow the 1 amp fuse under the playfield.
If I replace the fuse everything is ok for maybe 2 games, maybe 22 games and then the fuse blows again. Each time it is replaced everything is ok.
It seems to be blowing when the ball is being ejected from the outhole at the start of a turn.
When the kicker eject the ball it seems to have varying strength and it fails to kick out the ball at the 1st attempt once or twice every 3 or 4 games .
I am new to this so could do with a few pointers of where to look.

Thanks.
 
Firsr thing to check is what the 1A fuse under the playfield powers.
Do you have a schematic?

Sent from my SM-G960F using Tapatalk
 
Andy_B said:
Firsr thing to check is what the 1A fuse under the playfield powers.
Do you have a schematic?

Sent from my SM-G960F using Tapatalk
Click to expand...

It powers all the solenoids except the knocker.

Try stripping down and cleaning the eject kicker as a starter for 10.
 
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Moonraker said:
It powers all the solenoids except the knocker.

Try stripping down and cleaning the eject kicker as a starter for 10.
Click to expand...
Moonraker,
Ok, this will be a first for me.
I have realised that the fuse has only blown on games with more than 1 player. This is also the point where the machine resets the targets and knocks down the targets that have already been scored on the players previous turn. The latest blow has only dropped the 5 ball target. I do not know what was already down. if it continues after stripping down the kicker,I will have to keep track of what targets are down and see if there is any common denominator with target resets.
 
Hi Andrew, based on what you have seen above, it could be one of the coils on the drop target bank. There are 7 drop targets and 7 coils that can pull back down each target after the main reset coils have reset the whole bank of 7.

If you have a multimeter test the resistance of each coil - should be about 50 ohms. Each coil also has a diode across it, it could be a faulty diode too. Coils are CV31-2000 or CJ31-2000

To figure out which coil is the one blowing the fuse:
start a 2 player game
player 1 - knock down target 1 and drain the ball,
player 2 - score something then drain the ball - see what happens when it switches back to player 1 - it will reset the 7 targets and then drop the first one. If it doesnt blow the fuse, then knock down the next target #2 and repeat, until you find which one causes the problem.
 
Does it have the correct 1a fuse in it ? Pinball machines use a mixture of regular fuses and "slow blow" ones that allow momentary surges in current without blowing.

The under playfield fuse is probably meant to be a slow blow one
 
@Widnesbernie now you've provided more information we can address that.

You still need to strip down and clean the eject kicker mechanism to help the ball eject cleanly and every time.

You also need to strip down and clean (or better still replace) the parts for the 7 bank drop target mechanism, it's drawing too much current for the slow-blow 1 Amp fuse when attempting to reset. Dirty, rusty and worn out mechanisms provide too much resistance which results in the drawn current when trying to reset them. I'd also tackle the remaining drop targets (bonus multiplier and 8 Ball) as they probably need doing, it will prevent the problem moving from one area to another.

Grab a set of new drop targets and replace them whilst you're stripping the mechanism down, old drop targets are brittle and can break easy. Nothing worse than having one break after have just taken it apart...
 
Thank you for all the help. Something has come up so it will be a few days until I can get back to the machine.
I also need to order parts then before I start.
In answer to one of the above, yes I have been using 1 amp slow blow fuses, waiting for some more to come.
It looks like I'll be spending some time on Youtube before I attempt this.
One more question, can a diode be intrmittently faulty or do they just pack in?

Once again, thank you.
 
Widnesbernie said:
One more question, can a diode be intermittently faulty or do they just pack in?
Click to expand...

Yes, they can. A break that still touches is normally the case. With the power switched off, grab hold of the body of the diode and give a small tug. to see if there's any movement (from a broken leg). I'll be surprise if it's a diode causing your issues.
 
I have ordered coils from Marco's.
If I play in one player mode the fuse has stopped blowing. However, it has now lost the background sound and is stuck on shoot again.
 
The solenoid board made a few clicking sounds and the shoot again went out.
I had set setting to 3 when I got the machine, it had changed itself to 2.
May have to put my hand in my pocket and get it looked at by someone who knows what they are doing
 
It now seems to have settled down. It is awarding an extra ball on the 1st ball only for each player as the ball passes through the A or B gate at the start of a turn. Tried dropping the ball down the centre on 2 player setting so no drop targets used and it does the same for each player.
 
Mmmmmm

I feel your pain. I think you are in for a crash course in pinball repair.

Good news is that your game fundamentally works and sounds complete

The most likely causes for your problems are...

1. Knackered coil, that is probably the source of your fuse blowing

2. Bad connectors. Both the pins on the boards and the sockets in the connectors oxidise. If you remove and reseat connectors a couple of times with the power off, it can temporarily clear a fault like this. Do so methodically so you may be able to isolate where your problem is.

Gently cleaning pins with very fine sandpaper (400 grit plus) is almost inevitable on a game of this age. Repacing connectors is a pinball right of passage.

So step 1. Remove and reseat - see if you can find problems. Focus on the known problem
Step 2. Clean pins. If necessary ..... then
Step 3. Replace connectors

3. Bad voltages. Your boards have a number of TPs or touching points. The manual will show you where they are and what the voltages should be. Using a multi meter, check these out

Report back
 
Thanks for all that. Long term plan is repin connectors (wow, there are so many), and replace boards with Allteks. Never done anything like this before.
Currently nursing a broken hand, my dominant one. Thought the splint was coming off this week, not so, possible complications, will find out in a fortnight.
Gives me time to build a stock of spares and carry on reading and you tube watching.
 
I am working my way slowly through some jobs. Memory coil replaced, drop down targets replaced.
I am currently rebuilding the flippers but have accidently deleted my photo of the bottom left coil & switch wiring. Does anybody have a picture of the coil & switch that I can refer to?
 
Managed to get it from a couple of other pictures. I found the thread already on here, but my wires are not all the same colour.
Also the centre coil wire is yellow on my machine and goes to the left hand lug on the eos, the picture shows it going to the 2nd lug from the left.

1620569307387.png
 
Ok. Nearly finished the first few jobs.
The only problem I appear to have added to the machine is when I drop the 5 target it registers ball 5 & 6. If I drop the 6 target it also registers balls 5 & 6.
To eliminate a false switch contact I have put a piece of card between the ball 5 contacts and both balls still register. I have moved the piece of card to between the ball 6 contacts and they both still register.
I have had the unit apart and replaced the ball 5 memory coil.
Could anybody offer up my next move.
 
Hi Andrew, The switches are in a switch matrix, and rely on the diodes to ensure signals don't get mixed up. First thing to check is the switches are wired up correctly and the diodes are the right way round and "in-circuit" it is easy to misconnect up a switch and leave out the diode. I did it once when I took a drop target assembly out and desoldered all the switch wires.

Also any other switches playing up - especially the ones on rows 4 and 5 , or col 2 as per switch matrix diagram below:

1620843640583.png
 
2 likely causes

1. A short on ball 5 and ball 6 switch circuits. Remove the relevant connector from the mpu and see if there is continuity between the relevant wires. Also check the relevant pins on the board for continuity to see if a short exists there

A food tip for pinball machines ghetto repairs is to see how a known good circuit behaves, and compare to the bad one. So you could check 5 and 6 , then 4 and 5 to see if there is a difference

2. Check switch diodes on 5 and 6. If you are lucky, one is goosed
 
Wow, that was quick.
I didn't remove any switches or diodes when the unit was out of the machine. The balls were registering ok before I removed the drop target unit.
I have 1N4004 & 1N4007 diodes, but they are different from the diodes on these switches. Are they the same?
I have tested the diodes and I am getting a reading of about 5v in one direction only on each diode.
 
To test diodes, you need to turn power off and use the diode function of your meter. Do a youtube search on diode testing.

If it all worked before you took it apart, something physical has probably changed. It is probably not a diode issue. It sounds like a short. A solder splat.

Did you desolder anything ?
 
You can often focus on "what has changed"

Did you desolder or mess about with any switches?
 
I didn't mess with any of the switches. the only disturbance they had was when I was removing the panels on the unit and laid it down a couple of times on the table.
I removed the panels on the unit as I did not know the memory coil unit was only held on by 2 screws.
I replaced the ball 5 memory coil and all the drop targets.
I will take it out of the machine again and see if I can spot anything untoward.
 
Smells like a short circuit to me. Those drop target banks might have bare wires on them? If there is a bare wire, have a good look at that
 
Short was 2 diodes having a kiss and a cuddle.
I now need to look at the flippers. Rebuilt but right hand one is sticking.
 

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sticking if you have rebuilt,is usually you’ve tightened one of the flipper shaft screws ito tight before the other one so it knocks it off kilter. loosen both and tighten each slowly in turn.
 
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