Flipper fuse blew. Next steps and diagnosis - transistor/diode replacement

[DaveA]

Right so i am definitely out of my depth here but trying to explain what I am trying to do... I knew pins were complex when I started out but definitely entering some murky waters here

I was playing with my friend and chatting idly whilst the left flipper button was pressed and in up right position (it is how you trigger the skillshot)

On the plunge the flipper stopped responding. On lifting the playfield you could see the fuse had gone on left flipper.

I moved the right flipper fuse from the right to the left to see if it was just a bust flipper, and the flipper then triggers but sticks in the up right position. I have therefore determined it isnt the coil thats blown as then the flipper wouldnt lift.

So my diagnosis is that it is the transistor or diode on the board under the backbox and have found in the manual which one that is. I have tracked it down to transistor Q15 & diode D15. I have taken the board out of the backbox and identified the parts on the underside of the board.

I have sourced a replacement transistor, diode and flipper fuse.

Now it so gets to unsoldering the transistor and diode as shown in picture, and putting the new stuff in...

I had a few queries before taking the plunge (or on determining whether I need more specialist help)

1. Does diagnosis seem to hold or am I barking up the wrong tree entirely with this fix? I dont want to start messing with stuff that doesnt need to be messed with, for obvious reasons.
2. If i mess up with the solder how much is a new board?
3. When heating up the existing solder what technique needs to be employed to remove the transistor/diode and ensure that it doesnt just melt and spread? I have attached pic of the iron planning to use?
4. Any other tips for removal of old parts and adding in the new? The transistor looks like it will slot in dead easy but the diode has very long legs
5. What order would you do the fix in to reduce requirement of doing more than is absolutely necessary?

 

[AlanJ]

What game?

If you have a DMM you can test the transistor (on Diode test setting), compare across any 2 legs both ways red/black then reverse black/red leads. so 6 readings in total. Compare to other similar transistors on the board. if it's faulty it will be different to the others on the board - e.g. you'll most likely find a short circuit where other transistors are not. If so, it's dead and replace it.

Cut it off first then desolder each of the 3 leg pins that are left individually. Clean out the holes with a solder sucker or wick so you can install the replacement.

Your soldering iron looks to have a pointed tip - I find you need more heat surface for power transistors, so an oval angled tip is usually much better.

 

[DaveA]

Game is a metallica pro.

Are you suggesting the diodes/transistors can be tested more from the operator settings screen on the game? Or maybe more of a benefit to use a multimeter first?

There is no specific sign of either the transistor or the diode being burnt out to be honest.

Flipper fuse was defo burnt tho

 

[drhex]

Q14 should be upper PF left - Q15 is lower left according to the manual on ipdb. No offense but try soldering on some old board first, you need a solder sucker or wick at least and ideally something temperature controlled.

 

[AlanJ]

Game is a metallica pro.

Are you suggesting the diodes/transistors can be tested more from the operator settings screen on the game? Or maybe more of a benefit to use a multimeter first?

There is no specific sign of either the transistor or the diode being burnt out to be honest.

Flipper fuse was defo burnt tho

I was suggesting test with meter as you have already removed the board.

 

[DaveA]

Now working, thanks all (especially @AlanJ for helping with the transistor support)

Thanks all means a lot