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HS2 getaway I’ve killed the pop bumper !!

Freespawn

Freespawn

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Jun 1, 2018
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Southampton
Hi all whilst trying to sort out a Backbox Gi problem I took the power driver board out and noticed an old repair and a few dry joints after sorting this out and putting back in all seemed ok until smoke started to come out of the cab !! Panic !! Turns out when putting it back in I had pushed the old repair onto another resistor and have now killed the left pop bumper coil and possibly other components on the board 😬😢
Would you think it’s killed the transistors and other bits ? Kind of annoyed I didn’t repair it properly but as it was working i left it as it was.
Pic of board before (I also repaired a broken trace to the chip above as it was broken, unless it was this that made the bumper stick on ?? 😲 any advice would be greatly received
 

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Old, dodgy repair nudged into creating a mystery short circuit on the driver board...

Well, a dead transistor is just the first item on your list of worries now. See roasted R82, D19 and the destroyed through-holes by them. Q48 99% is now dead. Unlikely that anything else is damaged, short circuits destroy the first component in the new path that isn't capable of taking the complete power of the circuit. Everything downstream past the short won't even get power until the short burns itself away, and even then that depends if the circuit is still a complete circuit after whatever component pops, has popped.

Therefore I'm not sure why you reckon the coil is toast - it is almost certainly fine. You can't cook a coil with electricity if you've shorted all of it's power in the backbox.

All of that is in addition to what was originally wrong with the game - and how much was or wasn't fixed by that dodgy bare wire repair.

I really don't recommend repairing circuit boards that contain significant power if you're not 100% sure how to repair the damage they can do to themselves when faulted. Realise that all of the power you can see on the playfield, has to come from that power board...
 
Freespawn said:
Hi all whilst trying to sort out a Backbox Gi problem I took the power driver board out and noticed an old repair and a few dry joints after sorting this out and putting back in all seemed ok until smoke started to come out of the cab !! Panic !! Turns out when putting it back in I had pushed the old repair onto another resistor and have now killed the left pop bumper coil and possibly other components on the board 😬😢
Would you think it’s killed the transistors and other bits ? Kind of annoyed I didn’t repair it properly but as it was working i left it as it was.
Pic of board before (I also repaired a broken trace to the chip above as it was broken, unless it was this that made the bumper stick on ?? 😲 any advice would be greatly received
Click to expand...


If you want to send to me then i can take a look and fix it all no problem, but unfortunately it wont be free. Get in touch directly if you want to send me it.
 
Coil is definitely dead it released it magic smoke and got very hot 🥵
I’ve orderd the components to repair it hopefully repairing the broken traces and replacing the transistors and resistors should sort it out :) have also orderd the chip that drives it as that’s been replaced in the past too anyone got a pic of the back of the board so I can see what it should look like ?
Many thanks for the responses so far :)
 
Freespawn said:
Coil is definitely dead it released it magic smoke and got very hot 🥵
I’ve orderd the components to repair it hopefully repairing the broken traces and replacing the transistors and resistors should sort it out :) have also orderd the chip that drives it as that’s been replaced in the past too anyone got a pic of the back of the board so I can see what it should look like ?
Many thanks for the responses so far :)
Click to expand...
Not knowing how long you inadvertently left the coil cooking, the coil may or may not be dead - coils, especially older ones, can get bloody hot and start smelling before they cross the point of no return. Even smoke may not be the death of the coil, it may be the paper sleeve burning before the coil's enamel on the wire. Of course if the coil wire's enamel insulation is what melted and smoked, it's done for.

I must admit that your wallet will thank you in the long run if you diagnose failed parts before you start replacing parts. On these kinds of boards the ICs are NOT the first place I would be looking to repair faults with coils, especially when there was clearly track damage/a bad repair, or failed transistors. The transistors failing either spontaneously or from a failed coil diode is much more likely.
 
I have also ordered the diodes. The machine was working fine apart from the dry joint on the gi to backbox , the diode lead is the bare wire you can see in the pic this touched the end of a resistor R81 blew the fuse and cooked the coil
 
By coil diode, I meant the ones physically attached to the coils:
391793_orig.jpg

When those fail, the allow back EMF from the coil to travel back to the transistor, which kills the transistor not immediately but usually quite quickly. They're frequently overlooked, sometimes missing from clueless repair attempts on the coils themselves, and they're all much more likely to fail than the ICs.

Now, that aside as it's (possibly) not relevant to your current issue...

Avoid the temptation to rush through the job, as the schematic for the game can tell you everything that you'd need to know, in addition to what you see in the backbox... (irrelevant parts blanked out)

Untitled.png

If you've ended up with the worst case scenario of shorting 50v R81, then Q47 and R78 are all in line before the IC has the possibility of getting damaged, and those components look fine to me. If U4 was exposed to 50v it would be extremely obvious. Not sure why the fuse would be blown if the fuse didn't blow before the coil fried. Maybe if Q47 also failed under exposure to 50v.

If you just grounded out Q48 and locked on the coil's high voltage, then all you'll have done is cooked the coil. Nothing else would have happened as the circuit is designed to ground out 50V via Q48.

I'm not sure we've got the complete picture of what has happened.

Don't just shotgun it. The boards are old and they will not easily tolerate a lot of soldering so it's counterproductive replacing parts that aren't broken.
 
Thanks again for the input I repair photocopiers for a living so am quite used to repairing boards and the like :) just not so sure on the pinball side of things :)
Can’t see any diodes on the pop bumper coils ?
 
I also added the purple wire as the trace was looking suspect on the board where it’s burnt . Do you think the previous op might have done something else to the board to bypass that trace ? I also Re attach’d the solder to the trace below the diode leg that was the bad repair unless that wasn’t supposed to be attached to that point :/ couldn’t find a pic online of what the back of the board traces should have looked like. And the fuse that blew was f104
Thanks again
Dan.
 
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Freespawn said:
Thanks again for the input I repair photocopiers for a living so am quite used to repairing boards and the like :) just not so sure on the pinball side of things :)
Can’t see any diodes on the pop bumper coils ?
Click to expand...
Fair enough! I wasn't sure of your expertise level - for me it's better to risk being a patronising c-nut than letting someone enthusiastic and new dig themselves further into a hole; it happens alarmingly often.

Sorry, brain-fart - HS2 isn't going to have any diodes on the coils.

Freespawn said:
I also added the purple wire as the trace was looking suspect on the board where it’s burnt . Do you think the previous op might have done something else to the board to bypass that trace ? I also Re attach’d the solder to the trace below the diode leg that was the bad repair unless that wasn’t supposed to be attached to that point :/ couldn’t find a pic online of what the back of the board traces should have looked like. And the fuse that blew was f104
Thanks again
Dan.
Click to expand...
Assuming the other end of it is just following the thin trace, your purple wire is bang on. It's likely that it was always a marginal trace. I don't much faith in the original repair to be honest, it's likely they did nothing special and it either worked temporarily and what was left of the tiny trace finally burnt away over time just from plain old increased resistance, or it never worked again and they just said, sack it, it's just a pop bumper... That or it fell off. It's not as if there's much room on the top side of the board to easily add repairs. I wouldn't worry about it now you've sorted it.

F104 blowing is really disappointing that it didn't blow before the coil melted.

EDIT: I know what you're looking at now re: the solder trace you're unsure of - yes, it's supposed to be connected. That's the 50v trace. If it wasn't connected then the coil driven by Q50 wouldn't get 50V; which for reference, is the top pop bumper. Q48 is for the left bumper
 
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Ok so parts arrived think I have repaired the pop bumper ok but some of the flash lamps are on permanently and also the lower left kick back solenoid is permantly on too 😤 think it’s killed other components
 
Ok got board back still issues do you think one of the CPU chips might have gotten fried ? The right hand pop bumper locks on when machine boots and the lower sling locks on also some of the inserts lights are not working :/
 
As was mentioning on PM, it sounds like a data line problem still, so if you can try just running the cpu and driver board as i mentioned without the other boards ribbon cables connected we can try to isolate the issue. Also if you note what feature lamps aren't working then i can cross reference it to
 
Freespawn said:
Hi all whilst trying to sort out a Backbox Gi problem I took the power driver board out and noticed an old repair and a few dry joints after sorting this out and putting back in all seemed ok until smoke started to come out of the cab !! Panic !! Turns out when putting it back in I had pushed the old repair onto another resistor and have now killed the left pop bumper coil and possibly other components on the board 😬😢
Would you think it’s killed the transistors and other bits ? Kind of annoyed I didn’t repair it properly but as it was working i left it as it was.
Pic of board before (I also repaired a broken trace to the chip above as it was broken, unless it was this that made the bumper stick on ?? 😲 any advice would be greatly received
Click to expand...
The Board looks perfectly "repairable" however those power transistors do pull a fair amount of current. Be VERY careful not to short out the PCB tracks when soldering in track replacements and when done and checked and working I recommend several layers of thinly applied Araldite to ensure the repairs stay physically in place. I see that the Molex connectors on the board don't appear to have been resoldered and while out I would suggest they are done as well because almost certainly you will have "dry joints" on the Molex pins (every machine that old does)
 
AndyB53 said:
The Board looks perfectly "repairable" however those power transistors do pull a fair amount of current. Be VERY careful not to short out the PCB tracks when soldering in track replacements and when done and checked and working I recommend several layers of thinly applied Araldite to ensure the repairs stay physically in place. I see that the Molex connectors on the board don't appear to have been resoldered and while out I would suggest they are done as well because almost certainly you will have "dry joints" on the Molex pins (every machine that old does)
Click to expand...
Thanks for the reply the driver board has been repaired by Jim but would appear the cpu board was damaged in the short too so that’s now on its way to him for repair :)
 
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