Hey All - I'm working on a Panthera, and I'm having a bit of an odd issue. The leftmost drop target bank is trying to reset, but it seems too weak to complete the action. It is definitely receiving the command to perform the reset at the proper time, but just doesn't seem to have the umph to do it. The coil sleeve has been replaced and the plunger moves freely as it should, so it's not mechanical in that sense from what I can tell.

I grounded the tab on the driver board (a Rotten dog board) and the coil fires perfectly fine, with full strength. It resets the targets with no issue. So I know the coil can do the job, but for some reason doesn't seem to have the strength to do so when it should during a game.

Anyone have thoughts on what might be causing this?

Okay, I'll go repin it and see if that helps. Just out of curiosity though, why would it fire perfectly fine when I ground the tab on the transistor if the connector is the issue? Wouldn't that bad connection still be an issue in that case? Or does grounding the tab circumvent that potential problem?

Okay, interesting. I was wondering if that was the case. I'll try and sort out the proper one to repin. It's the punch-down style, which I had sometimes. If I remember correctly though, I can reuse it with regular pins.

I repinned the associated portion of the connector, but no change. I decided to take a closer look at the driver board. It's a Rottendog, installed by the previous owner, and I had (apparently incorrectly) assumed it was stock/new. I looked closer at Q58 (Solenoid 2, the one I'm having issues with) and I noticed it was an IRF540Z transistor. Someone replaced the original transistor that came on the board (obvious from the soldering), and all the other transistors are 13N10L.

A quick search on Pinside resulted in a thread where another member was told that IRF540 is *not* a replacement for 13N10L. The correct choice would have been an IRL540 / IRL540N.

I actually have a couple of those on the way from GPE right now, so my plan is to swap the IRF540Z for an IRL540N

frunch chuckwurt Please feel free to chime in if you think I'm on the wrong track. Thanks!

Yep mofset. Looking closely at that area of the board, it's a little darker, slightly browned. So I'm guessing the transistor that was there originally cooked. Resistance on the coil is fine, and as noted above it fired okay when the tab was grounded, so who knows why the transistor went. The board could have been in a totally different game before this one, I'll have to inquire with the previous owner.

I'll keep everybody in the loop. Thank you guys as always for the help. If this doesn't solve it, I guess we'll be doing some more troubleshooting together

frunch I will have to take a look, thanks. Yeah I think the diodes are underneath the play field on this one, but I'll check.

Here are the pics I mentioned

Panthera_Rotten_Driver - Copy (resized).jpg

Panthera_Rotten_Driver1 - Copy (resized).jpg

Circling back around on this issue. I replaced the transistor with the IRL540N and sure enough the drop bank is resetting perfectly now. I'm guessing the person that replaced it originally figured there wasn't much difference between the "N" and the "F" version of the IRL540, but the specs say otherwise.

Thanks for everyone's help!