Bally Lost World: Visible Sparks at J1 J3 Transformer Assembly

I'm getting close to being able to properly turn this machine on under load, but I've got one hang up. I've almost completely rebuilt this transformer assembly, repinned the power connectors, and added jumper wires based off Clay's guide. When the machine is turned on, after ~1 minute with only J2 plugged in, I visibly see sparks around J1 and J3. They're not constant; they come and go. All TP voltages tested good.

I did try desoldering J1 and taking a look underneath to see if there was excessive flux, or bridged solder, but didn't notice anything out of the ordinary. I did notice that when I have the jumper wire going from J1-5 to J3-10 (the dark blue one), I get continuity between J1-5 and J3-1thru4. Is this normal?

The cabinet power switch was completely missing when I got this machine, and in my initial attempt to wire one back in, I did it completely wrong. This led me to replacing the BRs twice in total. Is there a chance I screwed the transformer in doing this, and that's why I'm getting these sparks?

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#2 3 years ago

PIP

Quench

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The bridge rectifier pins on the back of the rectifier board should be cut, they might be shorting against the mounting plate when the board's installed.

#3 3 years ago

DNH

Knxwledge

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Quoted from Quench:
The bridge rectifier pins on the back of the rectifier board should be cut, they might be shorting against the mounting plate when the board's installed.

Thanks for pointing that out. I will cut them, but when I did the first set of BRs and I had cut the leads, I had the same problem, and I had the board off and on the mounting plate today for testing. Regardless of if it was on or off the plate, I saw the sparks

#4 3 years ago

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Quench

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OP
Quoted from Knxwledge:
I did notice that when I have the jumper wire going from J1-5 to J3-10 (the dark blue one), I get continuity between J1-5 and J3-1thru4. Is this normal?

This is normal, the continuity you're measuring is actually the G.I winding in the transformer.

None of the fuses are blowing?

#5 3 years ago

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Quench

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BTW, it looks like most of those new fuse clips are soldered in backwards which will cause issues of poor conectivity with the high current circuits as you'll be getting less surface contact between clip and fuse.
The clips need to be flipped around 180 degrees.

#6 3 years ago

DNH

Knxwledge

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Quoted from Quench:
This is normal, the continuity you're measuring is actually the G.I winding in the transformer.
None of the fuses are blowing?

No fuses are blowing

Quoted from Quench:
BTW, it looks like most of those new fuse clips are soldered in backwards which will cause issues of poor conectivity with the high current circuits as you'll be getting less surface contact between clip and fuse.
The clips need to be flipped around 180 degrees.

Oooooh okay, I didn't realize there was a right way and a wrong way to put them on. Can you point out an example of one that's soldered in correctly?

#7 3 years ago

ESK

sixpakmopar

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The fuse clips each have 2 tabs pressed into one end to prevent the fuse from sliding out. Those tabs go toward the end of the fuse.

#8 3 years ago

DNH

Knxwledge

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Quoted from sixpakmopar:
The fuse clips each have 2 tabs pressed into one end to prevent the fuse from sliding out. Those tabs go toward the end of the fuse.

Do you think that would be causing the sparking on J1 J3? I did notice they had a tendency to pop out of the holders if I moved the board around

#9 3 years ago

ESK

sixpakmopar

Pinside member

do not know but regardless they should be able to firmly hold the fuses in place. A properly held fuse needs to be pried loose to remove. They do not just pop out.

#10 3 years ago

BOB

CanadianPinball

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5y 40,550 407

Quench has pointed out the BR legs already but take a look at the other things I see. Some might be OK and just look funny b/c of the picture angle. In particular, is the blue wire too exposed and arcing? The others I circled just need better soldering.

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#11 3 years ago

DNH

Knxwledge

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Quoted from CanadianPinball:
Quench has pointed out the BR legs already but take a look at the other things I see. Some might be OK and just look funny b/c of the picture angle. In particular, is the blue wire too exposed and arcing? The others I circled just need better soldering.
[quoted image]

I cut the BR legs, fixed the fuse clips, resoldered some of the wires, and trimmed down most of the jumper wires I put in. It appears to have fixed the problem. I've let it run for ~3 minutes, power cycling it every minute, and I haven't seen any sparks on either side of the board. Thanks!

On another semi-related note, I accidentally screwed up when recrimping the power connectors, and both parts of the crimp are gripping bare wire strands. I know now that it's supposed to be one of the crimps gripping the insulation, and one gripping the wire strands, but only realized this after. Will this cause issues? All the wires I crimped this way are very tight.

#12 3 years ago

DNH

Knxwledge

Pinside member

OP
Quoted from Knxwledge:
I cut the BR legs, fixed the fuse clips, resoldered some of the wires, and trimmed down most of the jumper wires I put in. It appears to have fixed the problem. I've let it run for ~3 minutes, power cycling it every minute, and I haven't seen any sparks on either side of the board. Thanks!
On another semi-related note, I accidentally screwed up when recrimping the power connectors, and both parts of the crimp are gripping bare wire strands. I know now that it's supposed to be one of the crimps gripping the insulation, and one gripping the wire strands, but only realized this after. Will this cause issues? All the wires I crimped this way are very tight.

After coming inside to write this post, I went back out in the garage, tried turning it on again. To my chagrin, new problems, NEW SPARKS (and smoke)! This time coming from the middle BR. Happens as soon as I turn the machine on. Still no sparks on J1 J3 though LMAO. No fuses blown. I got these BRs from Big Daddy. Is there a chance I got a bad one?

#13 3 years ago

DNH

Knxwledge

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Ugh okay, so nothing looks visibly damaged or burnt. I couldn't figure out if it was the middle or right BR. I pulled out the right BR, tested it out of circuit and it's completely fine. Tested the other 2 BRs in circuit and they tested fine as well. Using diode check, all appropriate checks resulted in ~0.45 on the meter.
No fuses are blown. I tested the VR, and I'm not sure what it's supposed to read, but with it out of circuit, it kept rising from ~20mOhm to over 100mOhm, it kept changing the 3 or so times I tested it. So I'm going to say that's probably faulty. R1 (600ohm resistor) tests ~618ohm. If anybody has any pointers, please let me know! Still no sparks coming from J1 J3. One step forward two steps back I guess

#14 3 years ago

PIP

Quench

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OP
Quoted from Knxwledge:
I didn't realize there was a right way and a wrong way to put them on. Can you point out an example of one that's soldered in correctly?

For reference, below is an example of how the fuses sit in the clips - one side of the clips has end blockers. Your fuse clips looked like the blockers were oriented on the inside instead of the outside

OP
Quoted from Knxwledge:
I tested the VR, and I'm not sure what it's supposed to read

If VR1 has come to the end of its life, it will blow out.

Any signs of blackness after the smoke started?

Have you measured the test points to see if your voltages are in spec?
IMG_0008a.jpg

#15 3 years ago

ESK

sixpakmopar

Pinside member

The lack of a crimp on the wire insulation should not pose an issue. If the wire is bare outside of the housing that could be a problem or if someone were to pull on the wires hard enough that could move the insulation to expose bare wires

#16 3 years ago

DNH

Knxwledge

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Quoted from Quench:
For reference, below is an example of how the fuses sit in the clips - one side of the clips has end blockers. Your fuse clips looked like the blockers were oriented on the inside instead of the outside

If VR1 has come to the end of its life, it will blow out.
Any signs of blackness after the smoke started?
Have you measured the test points to see if your voltages are in spec?
[quoted image]

My voltages were good before this new sparking started happening. I havent tested them since because obviously Im not sticking my hand anywhere near a sparking board. On the old VR itself, it doesnt looked smoked, neither does that part of the board. It really looked like the smoke was coming from a BR, which is why I thought one blew. I wrote the voltages down, I will let you know what they were when I get home today.

#17 3 years ago

DNH

Knxwledge

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Okay, so *before* this new smoking/sparking, when everything seemed fine, these were the voltages I was getting:
TP1- 6.27 vDC
TP2- 160 vDC
TP3- 11.8 vDC
TP4- 7.29 vAC
TP5- 45 VDC

#18 3 years ago

PIP

Quench

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Do you have alligator clips so you can hookup your meter probes to the board? Then power on for a few seconds - enough to take readings from the test points?

Did you reconnect any transformer wires on the board - are they 100% in the correct "E" locations?

#19 3 years ago

DNH

Knxwledge

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Quoted from Quench:
Do you have alligator clips so you can hookup your meter probes to the board? Then power on for a few seconds - enough to take readings from the test points?
Did you reconnect any transformer wires on the board - are they 100% in the correct "E" locations?

I think I do have alligator DMM clips. Is it safe to do that to the board?

I never desoldered any of the transformer wires but I dont know what's been done to this machine previously so I will double check theyre in the correct position.

#20 3 years ago

ESK

sixpakmopar

Pinside member

I cannot see under the BR's but how close did you mount them to the board? Is one of them touching a leg of the ceramic resistor? The red disc? I would look closely at everything you worked on to verify it is correct. Check the wires you re-crimped to verify they were inserted in the correct locations.

#21 3 years ago

DNH

Knxwledge

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Quoted from sixpakmopar:
I cannot see under the BR's but how close did you mount them to the board? Is one of them touching a leg of the ceramic resistor? The red disc? I would look closely at everything you worked on to verify it is correct. Check the wires you re-crimped to verify they were inserted in the correct locations.

I mounted them about 3/4" away from the board, and made sure to bend the legs away from anything else on the board. I will double check my crimp job, and attach a picture when I get home.

#22 3 years ago

DNH

Knxwledge

Pinside member

Pics of everything potentially relevant to my issue. I checked the locations of the wires coming off the transformer and everything looks fine.

Line filter and switch replacements I bought and installed:
https://www.amazon.com/gp/product/B073RMZP3R/ref=ppx_yo_dt_b_asin_title_o04_s00
https://www.amazon.com/gp/product/B01MSWTEB0/ref=ppx_yo_dt_b_asin_title_o04_s00

I also realized I incorrectly fixed the fuse clip positions. They're all now consistently wrong lol. They do feel very tight, and I no longer have the issue of them popping out. Should I bother flipping them all around?

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#23 3 years ago

DNH

Knxwledge

Pinside member

Went back and double checked the BRs. Here's an example of one reading I got.

So within the circles are 2 legs of the 3 BRs. When I put the black dmm lead on the top and the red on the bottom, I got these readings for BR 1 through 3 respectively (Diode check):
.48
.5
.49

Now when I reversed the test probe positions, here's what I got:
.5
Open
1.16

I noticed this trend on all tests I did on the BRs. Is this normal?

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#24 3 years ago

PIP

Quench

Pinside member

OP
Quoted from Knxwledge:
I think I do have alligator DMM clips. Is it safe to do that to the board?

Just switch it on long enough to get voltage readings at the test points which will probably be about 3 seconds each. At least then you can get some idea which supply rail is abnormal.

BTW, have you visually sighted exactly where the sparks are coming from yet?

Also, you should get a more substantial heatsink on BR1 because it's going to run HOT. You can see long term PCB heat stress around BR1 and a little around the 20 amp fuse clips. Your board actually looks decent, they can get quite burnt up.

OP
Quoted from Knxwledge:
I also realized I incorrectly fixed the fuse clip positions. They're all now consistently wrong lol. They do feel very tight, and I no longer have the issue of them popping out. Should I bother flipping them all around?

I definitely wouldn't leave them backwards, at minimum you must correct the lamp fuse clips. They carry a lot of current and need maximum surface contact between fuse and clips.
The F5 G.I fuse clips should be high current capable clips. You may have noticed the originals were different material to the other brass clips for this purpose.

Are you running incandescent lamps or LEDs in this game?

OP
Quoted from Knxwledge:
I noticed this trend on all tests I did on the BRs. Is this normal?

BR1 and BR3 have ceramic resistors across them which makes diode checking them give some abnormal readings. You need to disconnect one leg of those ceramic resistors to isolate them from the bridges to get proper readings. The diodes inside the bridges will then give normal 0.5 readings one way and open the other way.

Find something to cover the power switch with so you don't actually touch the terminals. I use an old aerosol can plastic top and cut it in a way to create tabs so it can be screwed down. From factory they had a plastic dome covering the power switch.

EMI_Filter1.jpg

#25 3 years ago

DNH

Knxwledge

Pinside member

Quoted from Quench:
Just switch it on long enough to get voltage readings at the test points which will probably be about 3 seconds each. At least then you can get some idea which supply rail is abnormal.
BTW, have you visually sighted exactly where the sparks are coming from yet?
Also, you should get a more substantial heatsink on BR1 because it's going to run HOT. You can see long term PCB heat stress around BR1 and a little around the 20 amp fuse clips. Your board actually looks decent, they can get quite burnt up.

I definitely wouldn't leave them backwards, at minimum you must correct the lamp fuse clips. They carry a lot of current and need maximum surface contact between fuse and clips.
The F5 G.I fuse clips should be high current capable clips. You may have noticed the originals were different material to the other brass clips for this purpose.
Are you running incandescent lamps or LEDs in this game?

BR1 and BR3 have ceramic resistors across them which makes diode checking them give some abnormal readings. You need to disconnect one leg of those ceramic resistors to isolate them from the bridges to get proper readings. The diodes inside the bridges will then give normal 0.5 readings one way and open the other way.
Find something to cover the power switch with so you don't actually touch the terminals. I use an old aerosol can plastic top and cut it in a way to create tabs so it can be screwed down. From factory they had a plastic dome covering the power switch.
[quoted image]

Well well well, it appears it was the VR that took a dump because I did replace it for the hell of it, checked positions of the transformer wires, reinstalled BR3, and plugged it back in to get voltages. Lo and behold no more sparking or smoking. I let it run for a solid 20 mins, and I could tell the board was getting hot (which I know is normal), but nothing out of the ordinary. Voltages from all 5 test points tested very close to the numbers I was getting previously in post #17 with the exception of TP2 which was around 170 vDC this time. I am running fresh #47s in the entire machine.

Man, are you for real about that heat sink? Got it in the kit from Big Daddy, so I would have thought it would have been good enough. If you think it will be an issue, even in a home environment, point me in the direction of what one you would consider good.

On the topic of the line filter, that white wire was not touching the ground, it was just a bad camera angle. I wrapped the wire around the left post 1 full time and soldered the hell out of it. It's very secure, but to be safe I bent the non-soldered part of the wire as far away from the ground post as possible.

If problems come up again, I will make a follow up post, but for now, I'm going to fix my mistake with the fuse clips, and potentially order/install a new heat sink. Appreciate your guys' help very much.

#26 3 years ago

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Quench

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