Hi Guys

My Williams IJ started acting up, and resetting all of a sudden while playing (Actually i've seen it reset in attract mode also).

Tonight i changed C5, BR2 and Q1 with new components just like the set they sell here: https://www.pinball.co.uk/product/5-volt-rebuild-kit/

Unfortunately it didn't work. After playing for about 3-4 minutes the machine reset. And after that, every time i trigger a coil it resets again.

Before changing the components, some days there could be 4-5 games without any problems, and then the next day it would be impossible to complete a full game. So it's been a little on/off.

Is there a logical next step for me to check now? I am by no means an electronics expert, but i have been able to do most basic repairs until now with lamp columns/rows, coil/flasher drivers and so on... But nothing more fancy than that.

So just wanted to know if there was some quick tips to check out before i give up and load it in the van and ship it off to a pinball repair guy.

I don't know if it's worth mentioning, but i have not been able to trigger the resets by pressing / tapping on any of the cables or chips on or near the CPU board, so i dont think it is just a loose connection.

No i did not. Is there a specific connector you have in mind?

Also i just remembered that i forgot to swap C4 as well. That was really stupid when i had the board out anyways...

I just found this wiki i didn't know about until now about 5V resets (http://www.pinwiki.com/wiki/index.php?title=Williams_WPC#Game_resets). And sure enough it tells me that what i just did should have been the absolute last thing to do

Oh well, the board was already "hacked" with wires between the BR2 and C5, so someone before me already broke the connections in the "through holes".

So i did some more testing. Using the powerboard from my STTNG the machine performed as it should without any resets through a whole day of pretty heavy gaming.

Before i put the original board back in i put in a new C4 capacitor, and reflowed all connectors mentioned in the pinwiki reset section. I did NOT put new pins in, as all of the connector pins looked in fine shape. I also reflowed the 113 fuse for the 5V supply.

Within 2-3 minutes of playing the game with the original powerboard back in, it reset again. So this leads me to believe that the problem is indeed with the power board.

So since i have now rebuild the most common things in the 5V supply via C5, BR2, Q1 (5V regulator) and C4 i am not quite sure what the next step should be.

I measured the 5V at TP2 with the (working) STTNG board in at it measured 4.889 V (4.844 at pin 32 of the game rom). With the original board in (with a rebuilt 5V) it only measured 4.733 (4.677 at pin 32 of the game rom).

As i understand it the CPU board should have at least 4.8 volts? And since it only gets 4.733 (and slightly less after the connector) could this be the reason?

Are there other components i should check that could affect the lower 5V, or am i going to have to do the "hack" mentioned on pinwiki to raise the voltage by .2 volts using a 24 ohm resistor?