Hello Everyone,

I try to find help here, because i cannot find any response to this problem over the internet,
So here it is :

When I played my Space Jam, the right flipper always seems too soft, specially on "hold" position.
For cause : Q16 was replaced with IRF540... We all know this is not good.

So, i've decided to re-replace it with correct STP40N10L (or 20N10L).
But,
Since i've done this, i've got big big problem and cannot play the game anymore, here's the problem :

Since I push ONE time the button for the right flipper, It still on hold position, instantly kill Q16 (GND short), and after 2-3 sec burn the associated fuse !
I've replaced 3 times Q16, and always exactly the same issue...
Yes, i'm sure of my solders and components. (tested before soldering).
The resistance of the coil is good, and i've putted new diode on it, same issue...

I cannot find the problem (and understand it by the way...)

Do you think U2 (74HCT273) could be DEAD and giving me this problem ?
Or something else ?

Everything was fine with the IRF540 before... (Just the weak flipper)

I've somebody has any idea / suggestion it would be great

Sorry for my medium english, I'm From Belgium.

Thanks a lot !

Hello, Thanks for your response !
Yes, it's sure the diode is ok and of course soldered with cables and coil themselves

Hello,
If you talk about C255 + C247 and R16, I've changed C255 last time for trying.
Do you think should I change both the two + R16 AND a new '273 on U2 ?

Don't have '273 so I need to order one...

For the coil resistance, it's not the same coil on the left side, so not the same value, but when I've changed the diode on the right side, I've measured it and compared to coils resistance list, it was ok.

Thanks ! =)

Hello again,
I've received my new '273 ... (Better late than never...)
I've replaced it, and once again, a new Q16.

And, ...
No.
The problem is STILL PRESENT !
So it was NOT U2...

Unbelievable... What's wrong with this board ?!
I'm totally totally lost ...

Please, any help...

Hello again, Tried again another thing today, replace the 40N10L (Both Q15 and Q16) with the recommanded IRL540N and the problem is STILL PRESENT !!!
Now on both Flippers by the way !
This driver drive me crazy...

I'm definitively still looking for any help ...
Any idea, any suggestion ? This problem is very uncommon ...

No they are both locking and destroying respective transistor only when i push flipper button :-/