(Topic ID: 291325)

transformer short?

By Matthew2015

6 months ago


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  • 42 posts
  • 9 Pinsiders participating
  • Latest reply 4 months ago by EJS
  • Topic is favorited by 1 Pinsider

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#1 6 months ago

the transformer in my flash pinball is not acting right. it seems to be running too hot and also make cracking sound and smell after a few minutes.
some people say its a short or something to do with bridge rectifier. anybody had a similar problem like this?
i cant see anything wrong except for the blue wire that's has exposed wiring in multiple places .
what's the large capacitor to the left of the transformer for?

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#2 6 months ago

the blue wire is usually AC for the feature lamp bridge and looks like it is going to the filter cap negative lead which is usually a black wire. I think someone has screwed around with that wiring so I would be double checking it.

Figure out the wiring first. Test the bridges. Add the safety fuses, see pinwiki or other guides. If the bridge is bad AC side fuse will sacrifice itself instead of burning the transformer.

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#3 6 months ago

Yes! I agree with what BarakandI said - the wiring looks to have been fanagled with so compare it to the drawing he included. And extremely important -- add the fuses!
https://www.pinwiki.com/wiki/index.php?title=Williams_System_3_-_7#Additional_Fuses

#4 6 months ago

checked 6br1 and the positive violent wire goes to the capacitor first before they go to the 3P1 plug for lamps 16 vdc ,
and the negative black wire across from that should also go to the capacitor first then hook to the connector 3p2 right ,
could not find flash pinball power schematics but i thought these are pretty much the same.
if this is wired wrong , is this what is causing the problem?

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#5 6 months ago

because that negative black is wired directly to the 3p2 plug and not to the capacitor first.

#6 6 months ago

The ground wires are normally black. Seeing a color that usually caries AC in the same area going the filter cap is concerning. It doesn't really matter what wire colors as long as the circuit wired up right. Hard to tell from your picture what exactly is going on but it looks like one of the wire insulation has melted off so that is a pretty good sign something is wired up very wrong or a bridge is shorted.

Hopefully no permanent damage has been done but don't power it up until you are sure it is wired up right, the bridges are not shorted, and the safety fuse added.

#7 6 months ago

The blue wire going to BR1 is burnt. That is one AC leg from transformer. Second blue wire to BR1 is MIA, was apparently replaced by somebody with a yellow wire. Yellow may also be burnt since it looks a bit deformed at the top loop.
Take note of where the wires are, pull the quick connects from BR1 and test BR1 using a meter's diode test function. I'm leaning towards a shorted bridge rectifier. If so, replace with a GBPC3504 or GBPC3504L.

Before you power it up again - get yourself a couple inline fuse holders (e.g. Littelfuse 01550100Z) and 8A fuses and install them at the red "X" locations:

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#8 6 months ago

With the mess in the wiring - do yourself a favor. Remove the mess that somebody put in there and rewire it properly.
Two new blue wires from transformer to bridge rectifier.
Two new red wires from transformer to bridge rectifier.
Add two new fuse holders and 8A fuses.
New violet wires from bridge rectifier to cap and connector 3P1.
New black wires from bridge rectifier to cap and connector 3P2.
New faston connectors (or solder direct to bridge).
New contacts for connections at 3P1 and 3P2.
Maybe new bridge(s) for BR1 and maybe BR2.
Maybe secondary side of bridge rectifier BR2 as well.

Wire size - depending on overall length of wire:

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#9 6 months ago

If you determine that one or both of the bridge rectifiers might be defective, you can get some here:
https://www.pinballlife.com/mm5/merchant.mvc?Screen=PROD&Product_Code=KBPC3504&Category_Code=
They are not very expensive.
Might as well replace them both.
You can keep one for a spare if they are both not bad.

#11 6 months ago

okay , i think will replace all the wires because there are multiple exposed wires and some wire are not even the right color. like the yellow wires were added later to replace blue wires and red near the base of the transformer. and i think 6br1 bridge has a short . i tested both bridges with reading of .500 except that
that the positive and bottom wire of 6br1 had a low reading of .050 then would drop to zero. also the negative wire of 6br1 is not attached to the large capacitor first , it is directly attached to the 3p2 plug. and 6br2 negative wire has is attached to the capacitor then wired to the 3p2 plug so i think that is wired wrong .

i'm surprised that the pinball even turns with all this messed up wiring.
but i will get some new bridge rectifiers and redo all the wires and add fuses .

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#12 6 months ago

If you are so inclined, you could post pictures of some of that special wiring that you encountered in this area:
https://pinside.com/pinball/forum/topic/worst-hackrepair-you-ever-saw
It will not be a really bad one, but it could qualify...

#13 6 months ago

i guess the next thing to snice i need to rewire the transformer is take it out to have better look it it.
could i rewire new wires to the base of the transformer? is there some solder points for that?

#14 6 months ago

Leave the transformer in place (unless you can't reach the backside of transformer), you are only replacing the red and blue wires that go to lugs (solder points) on secondary side of the transformer. It takes a bit of heat to get the solder flowing on these so take your time.
The photo within post #1 shows the primary side of the transformer, opposite side not shown in photo is the secondary side which is where you would be replacing the wires.

Lugs #11 and 12 for lamps (blue wires), 13 and 14 for solenoids (red wires).

The transformer in photo of post number #1 actually looks pretty good. Only thing I would do is pull that brown primary wire away from lug #7 so that the lug doesn't chafe it's way through the insulation. And - in same photo, there appears to be a loose bit of wire under transformer that should be pulled out.

#15 6 months ago

An option to inline fuse holders is to add a couple fuse blocks to the right of the two bridge rectifiers.
Here is an example for the fuse block:
https://www.greatplainselectronics.com/proddetail.asp?prod=354001GY

#16 6 months ago

i did take it out it looks pretty bad.

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#18 6 months ago
Quoted from Matthew2015:

i did take it out it looks pretty bad.
[quoted image]

Yeah, that looks pretty nasty.
Perhaps those connections can be repaired.

#19 6 months ago

i thought there would be some solder pads for the wires since there are some on the front but it looks like those wires are tucked behind that brown paper covering. i do want to know if can replace the wires at the base if there is one and what size of wire i would need .

#20 6 months ago

Find a technician who will know how to repair that safely for you. It will be far easier and a lot cheaper than looking for a replacement - which may not be any better.

Like others have said - the very first job (forget the transformer for a moment) is to get some fuses installed before the bridges so things don't catch fire and burn your house down.

#22 6 months ago

That transformer is

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#23 6 months ago

Yes, perfect.

The transformer doesn't look cooked so I would try and find a technician to help connect new wires to it for you. $50 spent doing this should give piece of mind. A technician can also test the transformer on the bench to confirm it is OK.

#24 6 months ago
Quoted from pins4u:

Like others have said - the very first job (forget the transformer for a moment) is to get some fuses installed before the bridges so things don't catch fire and burn your house down.

#25 6 months ago

would 18 awg wire work for replacing the wire from the transformer ?
, i have all the correct colors to replace them with.

#26 6 months ago
Quoted from Matthew2015:

would 18 awg wire work for replacing the wire from the transformer ?
, i have all the correct colors to replace them with.

To be blunt, if you have to ask this question you probably shouldn't be playing around with the mains. It can and does KILL people every day, even those who know what they are doing!

#27 6 months ago

okay , i will get a technician to do it but i don't know where i would get somebody that knows about that stuff.

#28 6 months ago

okay , i will get a technician to do it but i don't know where i would get somebody that knows about that stuff.
don't they make a new transformer replacement for this by now? all i could find were original units that are untested that were selling for $100.
likely a technician would cost more than that if i found one.

#29 6 months ago
Quoted from Matthew2015:

it seems to be running too hot and also make cracking sound and smell after a few minutes.

A friend of mine bought an early Stern with a suspect transformer and it came with a spare transformer.
The suspect transformer was faulty. We hooked up power to the spare transformer and it did exactly the same as yours. Got hot, made crackling noises and a smell after about a minute of power. Luckily he had his own spare working transformer which he ended up using.
The measurable DC resistances of the transformer windings including the input winding were lower than his good transformer.

If I were you, I would disconnect all transformer output connectors from the power/sound boards including the two bridge rectifiers and three fuses next to the bridges so the transformer outputs are totally isolated. Make sure the hacked bare wires are not touching anything they shouldn't.
If it still exhibits the same hot/smell/crackling symptom, it's time to look for a replacement used transformer. There are no reproductions yet.

#30 6 months ago

this bridge rectifier work ?
its 4 pins are not exactly the same as mine.
https://www.marcospecialties.com/pinball-parts/KBPC3504-L

#31 6 months ago
Quoted from Matthew2015:

this bridge rectifier work ?
its 4 pins are not exactly the same as mine.
https://www.marcospecialties.com/pinball-parts/KBPC3504-L

Its rated 400V, 35A, so it is the same device.
They are pretty common.
I would not expect the photo to exactly resemble the device, but it is similar.

#32 6 months ago

Where is the OP located? I would be willing to check this transformer on my impedance bridge and repair the wires. But would prefer he be local.

#33 6 months ago

With the damage that close to the transformer itself, I'd be concerned that the windings may have also been cooked and damaged. I don't think I would really trust that transformer.

Personally, I would start putting feelers out for a replacement transformer.

There is this one on ebay, but shipping across the ocean might be a tad expensive: ebay.com link: Williams 15B6797 Transformer

An untested one, but it looks like it was in a flooded game, so it may be questionable: ebay.com link: Williams Pinball System 3 7 Transformer Assembly AS IS untested

This one may be promising: ebay.com link: Williams FLASH PINBALL Power Block Transformer 15B B797 Mepco 30000 uf Capacitor

#34 6 months ago

the one with the Williams FLASH PINBALL Power Block Transformer was one i was considering but it sold like 20 mins ago.

#35 6 months ago
Quoted from Matthew2015:

the one with the Williams FLASH PINBALL Power Block Transformer was one i was considering but it sold like 20 mins ago.

You gotta snap up those hard-to-find items quickly before someone else nabs them.

#36 6 months ago

I would guess that if there was an actual short in the transformer, there would have been a rather violent reaction, like an explosion or fire, or at least a blown 120V fuse on the input to the transformer. A problem with a bridge would create high current that would cause some heating in the transformer and possibly a buzzing sound. I think that is what is happening here, given the information that we can see at the moment. The same affect could be possible with a bad/damaged wire that has created a high resistance path to ground. My guess is that if the lead connections can be repaired, that the transformer is still ok. Some problem (like a bad bridge rectifier) on the low side of the transformer has caused it to get hot or buzz.

#37 6 months ago
Quoted from Matthew2015:

this bridge rectifier work ?
its 4 pins are not exactly the same as mine.
https://www.marcospecialties.com/pinball-parts/KBPC3504-L

Yes, that would work.
But heat slug bridge rectifiers (phenolic body, metal top) have lower thermal resistance (lower is better) than full metal body bridge rectifiers.

#38 6 months ago

i do know there is a 1 bad bridge rectifier and a connection that not wired correctly. i will get the parts i need then i will find someone that knows more about this than i do to put this together . so i will take a break for now .

#39 6 months ago

i am trying to as much as this by myself to learn about how all this works and how to fix it but i will get a someone that know more about to do it for me and show me how they do it. i will also look more into vid1900 guides on pinside.

i do know there is a 1 bad bridge rectifier and a connection that not wired correctly. i will get the parts i need then i will find someone that knows more about this than i do to put this together . so i will take a break for now .

2 weeks later
#40 5 months ago

still looking for someone to fix transformer .
i was wondering since the some wires would have to replaced , i know the wires need to be the same awg size but if i don't have that exact size , is it safe to replace wire a with a slightly bigger wire size or smaller wire?

4 weeks later
#41 4 months ago

i got someone to test and fix the transformer wiring .
it needed a new bridge rectifier and some wires changed that had exposed wiring.
so its all working good now.

#42 4 months ago

If it’s shorted….you’ll know….

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