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Black Knight Transformer


skids

Question

smoked my Black Knight transformer and am wondering why this may have happened?

 

Was playing my BK when it started to smoke, shut the power off and lifted the playfield to find the transformer smoking, stunk the house out.

 

just wondering if it maybe to do with my problem of the pop bumper and sling shots not working?

http://www.aussiearcade.com/showthread.php/53817-Black-Knight-pop-bumper

 

amy ideas why a transformer would start to smoke?

PB160073.thumb.jpg.05e4d9b46b7677d06435a10a6c0e2102.jpg

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smoked my Black Knight transformer and am wondering why this may have happened?

Was playing my BK when it started to smoke, shut the power off and lifted the playfield to find the transformer smoking, stunk the house out.

just wondering if it maybe to do with my problem of the pop bumper and sling shots not working?

http://www.aussiearcade.com/showthread.php/53817-Black-Knight-pop-bumper

amy ideas why a transformer would start to smoke?

 

That transformer setup doesn't look original.

Looks like the transformer has been changed and the 110v/220v adaptor plug has been removed.

IPDB Site picture:

http://www.ipdb.org/showpic.pl?id=310&picno=16004

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About the only thing that will toast a transformer is a VERY heavy load such as shorted bridge rectifiers/diodes.

 

I am unsure about exact Williams SS models but several of them needs to have a fuse fitted between the transformer and bridge for exactly this reason - I don't know if it is this model?? I could be completely on the wrong track here - if so, ignore my post.

 

This is a bit from Clays guides (with full credit to Clay):

 

******************************************

 

Adding Two Fuses to a System3 to System7 Games.

All Williams games prior to 1987 do *not* have fuses on the input side of the backbox mounted bridge rectifiers. This is a bad design, and one that Williams later fixed.

 

The two bridge rectifiers mounted to the backbox are the lamp matrix and solenoid bridge rectifiers. If either of these bridges shorts, or the large backbox mounted 30,000 mfd lamp matrix capacitor shorts, the main power fuse *should* blow. But if this single fuse was "over fused", a fire could result!

 

To fix this problem is simple. It requires two fuse holders (available at Radio Shack), two 8 amp slow blow fuses, and two pieces of 18 gauge wire. Here are the instructions:

 

In the backbox, beneath the power supply board, locate the bridge with the BLUE wires (6BR1, for the lamp matrix).

Using a 1/4" hex head sheet metal screw, mount a fuse holder right next to this bridge rectifier.

Disconnect one of the blue wires from this bridge (either blue wire, it does not matter). Often these wires are soldered to the bridge. The blue wires are the AC input wires to the bridge.

Solder this removed blue wire to one end of the newly installed fuse holder.

Solder a new wire from the other end of the newly installed fuse holder, to the lug of the bridge rectifier where the blue wire was originally disconnected.

In the backbox, beneath the power supply board, locate the bridge with the RED wires (6BR2, for the solenoids).

Using a 1/4" hex head sheet metal screw, mount a fuse holder right next to this bridge rectifier.

Disconnect one of the red wires from this bridge (either red wire, it does not matter). Usually these wires have lug connectors (but they could be soldered). The red wires are the AC input wires to the bridge.

Solder this removed red wire to one end of the newly installed fuse holder.

Solder a new wire from the other end of the newly installed fuse holder, to the lug of the bridge rectifier where the red wire was originally disconnected.

Install 8 amp slow blow fuses in both fuse holders.

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and, a smoking transformer also means the material doing the smoking is most likely the insulation coating for the transformer windings leading to shorted turns, therefore it would be a good idea to replace it in case of damage.
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That transformer setup doesn't look original.

Looks like the transformer has been changed and the 110v/220v adaptor plug has been removed.

IPDB Site picture:

http://www.ipdb.org/showpic.pl?id=310&picno=16004

 

hmmm looking at the ipdb it shows early BK transformer in the headbox, and later BK in the cabinet, my BK has both!! one in the headbox and one in the cabinet wtf?

 

looking at ipdb my has a relay in the headbox like the early BK, but i have a system 7 power supply

 

looks like i need to add fuses to stop future problems, if i can get my hands on another transformer, i'd be happy :D but they arent very common. Im not prepared to turn it on until i get a C02 fire extinguisher just in case

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PB160073.thumb.jpg.becfd7683801ca9d01882ce125c7df1c.jpg

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Unplug everything from the secondary side of the transformer and plug the machine in to the mains - that will soon tell you if the TX is toast - it shouldn't get even slightly warm, if it starts to heat up, it's stuffed, otherwise I would say it is probably OK - they are VERY robust and will take a lot of abuse.
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smokin can mean burnt insulation, and some or many shorted turns. really need to test both the input and output windings carefully

 

If the secondary windings are shorted that will place a load on the primary (even with them unplugged from the rest of the game) and the transformer will 'buzz' very audibly. No noise and no heat would be a pretty good indication that it has survived.

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hmmm looking at the ipdb it shows early BK transformer in the headbox, and later BK in the cabinet, my BK has both!! one in the headbox and one in the cabinet wtf?

 

looking at ipdb my has a relay in the headbox like the early BK, but i have a system 7 power supply

looks like i need to add fuses to stop future problems, if i can get my hands on another transformer, i'd be happy :D but they arent very common. Im not prepared to turn it on until i get a C02 fire extinguisher just in case

 

Is the extra transformer for the 50 volt coils?

Have a look where it connects to.

The later ones changed the flippers from 28 volt coils to 50 volts, so Williams added another transformer.

Perhaps your game is an early version and someone has retrofitted 50 volt flippers to your game.

Have a look at your flipper coils.

If someone hasn't done the job properly then maybe the 50 volts was going to your slings and bumpers and burnt them (or the fuse) out.

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Maybe as Boots says or maybe the extra transformer is a clumsy 110 to 240 V conversion?

 

You're going to have to trace some wiring to sort out what's happening. Do this with the power off.

 

There seems to be a label on top of the trf mounted in the base - what's it say?

 

Looks like the mains wiring (the grey circular cable) goes only to the cabinet trf? Is this so? How many terminals on the other side of the cab mounted trf and where do they go to? Are they the pink wires?

Do they go to the plug in the head that is visible in your photos that has one side white and one side dark reddish? Have a look at the links on the red side of this plug - the short white wire with red trace - this is how WMS pins of this vintage arrange the 110 / 240 V setup. Trace the white / red trace wires from this plug - they are normally the supply side and go through the cab on / off switch.

 

I'd also have a look around the ceramic resistor that is hanging in free air in the head box - doesn't look good and at least should be restrained / mounted somehow.

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Maybe as Boots says or maybe the extra transformer is a clumsy 110 to 240 V conversion?

Hmmm, initially I thought it was a stepdown transformer too but in the photo of his headbox you can see the mains jumper connector and it is red (220V), and the jumpers seem to look ok, if it was 100V then it would be blue.

Not sure why anyone would use a stepdown on any SYS3-7 because they can all be jumpered to 220V even the early ones like Hot Tip.

 

Definately as Fire_Power says though start checking wires with the power off, you will work it out.

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I serviced a firepower recently that a similar transformer installed in the bottom of the cabinet. Turns out that the original transformer had a winding short so the second transformer was installed to power the solenoids only.

 

Check your wiring.

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Hmmm, initially I thought it was a stepdown transformer too but in the photo of his headbox you can see the mains jumper connector and it is red (220V), and the jumpers seem to look ok, if it was 100V then it would be blue.

 

Hi Boots, I don't discount that you may be right - just putting up alternatives for investigation. As we say the OP needs to trace the wiring or get somebody who knows how to have a look. This will very quickly identify it as an extra coil supply or stepdown. Didn't know the story about red and blue plugs - but maybe I've only seen pins that were original imports. Given the amount of abuse and unknown mods that may have happened over the years, I'd be checking / confirming the jumpering in the plug. It's shown on the wiring diagrams I think.

 

Not sure why anyone would use a stepdown on any SYS3-7 ...

 

Because they don't know what they're doing?

 

... because they can all be jumpered to 220V even the early ones like Hot Tip.

 

As I understand it and have seen on several machines the plug jumpering arrangement for voltage selection only started at Sys6, prior to this the jumpering is done directly on the transformer lugs.

 

- - - Updated - - -

 

I serviced a firepower recently that a similar transformer installed in the bottom of the cabinet. Turns out that the original transformer had a winding short so the second transformer was installed to power the solenoids only.

 

Check your wiring.

 

A good reason to install the pre bridge fuses as suggested in post 3.

 

Also not sure how smart it is to leave the original transformer in service with failed winding - I wouldn't do it.

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ok

There seems to be a label on top of the trf mounted in the base - what's it say?
100VAC, TPW1100, JK15 SMD

 

Looks like the mains wiring (the grey circular cable) goes only to the cabinet trf? Is this so? How many terminals on the other side of the cab mounted trf and where do they go to? Are they the pink wires?

the pink wires turn white at a plug, then go to power supply

the mains wiring also goes from the cabinet trf to the head box trf, there is 8 terminals coming out of the head box trf

1 yellow wire going to the displays

3 grey wires to soundboard

2 red going to bridge rectifier (then from bridge rectifier, orange , Blue wires going to power supply)

2 blue going to bridge rectifier (then from bridge rectifier black and purple to green cylinder(capacitor?))

 

 

Do they go to the plug in the head that is visible in your photos that has one side white and one side dark reddish? Have a look at the links on the red side of this plug - the short white wire with red trace - this is how WMS pins of this vintage arrange the 110 / 240 V setup. Trace the white / red trace wires from this plug - they are normally the supply side and go through the cab on / off switch.
yes they go to the on off switch

I'd also have a look around the ceramic resistor that is hanging in free air in the head box - doesn't look good and at least should be restrained / mounted somehow.

 

added some photos, does that make it any clearer what is going on?

 

whilst fiddling around with the trf wires in the head box a screw fell free.....wonder if that what was causing the short??

1616218797_cabinettrf.thumb.jpg.5dc6c18c96ffdb744b644792ec918400.jpg

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As I understand it and have seen on several machines the plug jumpering arrangement for voltage selection only started at Sys6, prior to this the jumpering is done directly on the transformer lugs.

 

I can only comment on my Hot Tip, the transformer lugs were covered and not accessible and all of the primary winding wires went in parallel to the two pin power connector. I ended up using a standard 6 pin connector to essentially do the same as what the sys6 connectors do to run the windings in series.

 

[ATTACH=CONFIG]46497[/ATTACH][ATTACH=CONFIG]46498[/ATTACH]

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Also not sure how smart it is to leave the original transformer in service with failed winding - I wouldn't do it.

 

Not something that I would do either, but the machine was actually operated like that and is still going. So an effective repair/hack I'd say :blink:

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Is the extra transformer for the 50 volt coils?

Have a look where it connects to.

The later ones changed the flippers from 28 volt coils to 50 volts, so Williams added another transformer.

Perhaps your game is an early version and someone has retrofitted 50 volt flippers to your game.

Have a look at your flipper coils.

If someone hasn't done the job properly then maybe the 50 volts was going to your slings and bumpers and burnt them (or the fuse) out.

 

I disconnected the cabinet Transformer and the game appears to play as it did before minus the displays, so i assume its a fault from the pink wires coming out of the cabinet transformer, which change at a plug and turn to white at the power supply.

Now i used the continuity mode on the multimeter and one of these wires go to the display fuse F1, and the other wire is going to ground, is that correct? or is that where the problem is? or a short in the displays?

 

Can you tell from the previous photo if i have 50v flipper coils?, i have 34v at the flipper coils at the moment (with cab trf disconnected)

 

 

ps not a sparky, just a plumber:redface

P1110116.thumb.jpg.4dff18e9bb9eef6e6f0508db618dd541.jpg

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I disconnected the cabinet Transformer and the game appears to play as it did before minus the displays, so i assume its a fault from the pink wires coming out of the cabinet transformer, which change at a plug and turn to white at the power supply.

Now i used the continuity mode on the multimeter and one of these wires go to the display fuse F1, and the other wire is going to ground, is that correct? or is that where the problem is? or a short in the displays?

Can you tell from the previous photo if i have 50v flipper coils?, i have 34v at the flipper coils at the moment (with cab trf disconnected)

ps not a sparky, just a plumber:redface

 

OK now we are getting somewhere.

Looks like the extra transformer is to supply the 100v display voltage.

Probably the secondary winding for the 100v display supply has gone and someone has installed the extra transformer in it's place.

The wiring looks correct then.

Refer to this schematic:

[ATTACH=CONFIG]46595[/ATTACH]

 

OK back to your original problems.

1. Your transformer was smoking.

2. Your bumpers and slings aren't working.

 

1. One secondary winding on your transformer has already been damaged (someone has installed another transformer to rectify this), it could be smoking because the heat from the original short has damaged another secondary, or the 100v secondary is still shorting. I would suggest checking all your voltages to see if any others are out of spec or missing. I think the smart thing to do would be to try and source another transformer because if the original 100v line is still shorting it could cause the whole transformer to melt down anyway and possibly cause a fire.

 

2. Once you have checked the voltages, start checking for 34v at the solenoids.

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It looks like what's gone on is that there has been a problem with the display windings (100V secondary) in the head (original) transformer and they've added an extra transformer similar to the post described by Humpalot.

 

Look at the photo showing the head transformer and the blue and brown wires (terminals 1 & 8) take 240V and feed it to the cabinet transformer - you can see this in some of your earlier pics.

 

The pink wires coming from the cab transformer take 100V, which agrees with the marking on the transformer and through the connector feed to the power supply board, I'm still worried by what looks to be a power resistor floating in free air in this line. This agrees with your indication that it feeds F1 - should be 0,25A slow blow which is for the displays. The other wire pink / then white then goes to ground. This agrees with the wiring diagram I sent you.

 

I don't know how this fits in with a second transformer that was fitted for flipper powers supply. But if this is used there would be a second power suppy board. Do you have this? (As Iunderstand it early BK had sys6 psu boards) Maybe trace where the flipper wiring comes from and let us know?

 

I'd also be a bit worried about the yellow link on the bottom rhs of the power supply board -looks like a dodgy replacement of what should be a GI fuse.

 

Edit - Essentially the same answer as Boots - he posted whilst I was typing!

 

- - - Updated - - -

 

I can only comment on my Hot Tip, the transformer lugs were covered and not accessible and all of the primary winding wires went in parallel to the two pin power connector. I ended up using a standard 6 pin connector to essentially do the same as what the sys6 connectors do to run the windings in series.

 

[ATTACH=CONFIG]46497[/ATTACH][ATTACH=CONFIG]46498[/ATTACH]

 

Interesting. I've not seen in detail one as old as Hot Tip, but what you've done is great - safe, versatile, elegant and functional. Creative use of a leg bolt too :D

 

I have played with three older WMS machines; Flash, World Cup and Phoenix - all had the three pin plug (with just two pins used) and lugs on the transformer for line voltage adjustment. I guess things evolved or supply / design issues changed things. This is how my Flash looked.

 

Edit: Can't upload picture - will try later

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thank you for everyone that has helped me on this thread :D

 

where do you buy those fuse holders from?

 

will any transformer do? does anyone know if any of these will fit/suit?

 

http://www.pinballsparepartsaustralia.com/Products/29142-lah-power-sup.aspx

http://www.pinballsparepartsaustralia.com/Products/29315-corvette-parts01.aspx

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ok i'm back

had trouble getting the fuse holders - most people if they have 3AG fuse holders - only have the ones that go into a pcb, Jaycar had some that i had to cut up to suit, see pic.

 

My Black Knight has the displays working the way they were before YAY (1 digit out)

 

looked around for transformers, they seem fairly rare to find that would suit

I was thinking of using new displays such as pinscore which do no need the high voltage

I ended up getting new transformer from a company in Sydney called Tortech (part M1620) it might be a bit bigger than the old one (300watts) but the output is the same 100Volts which is what i needed for the displays.

 

I still have the pop bumper and slingshot issues, but i am wrapt i can see the scores again:D

 

thanks to everyone for their advice :041::041:

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P2140141.JPG.6c58ca86413ef4dbe6871c9f96b13e54.JPG

Edited by skids
update
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