Put some incandescents in there to test.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

can someone post the link for this mod?

I don't know if there is a thread for it. But basically you swap the TIP42/Resistor in the Lamp Column section-> IFR9Z34N MOSFET/Jumper.

Reason being is that the big cement resistor tosses off a crap ton of heat and by removing 8 of them you drop internal head temperature dramatically.

I do the mod to all my Williams 6/7 driver boards. I've never done it to Sys 11's as I have not seen any data on temperature drop. In the System 6/7 machines is pretty dramatic IRC. And but lower temp, you save baking the translight/backglass and caps, ect,,,,..

Don't get me wrong, I have it on the lower end of my todo list for the winter. System 6/7 were a must do. Every one of those boards I touch I retrofit. Even the special Hyperball hybrid driver board had it done and THAT has double the number of lamp columns... Sys 11's I just don't have out on the bench that often so it's not top of my list.

20140522_154853.jpg

I like the precision and uniformity of those jumpers Pat. Quality.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The new place for pinball repair info

Every 3-7 driver board i touch I do this mod on anymore. If you can avoid burning off that much heat, go for it. I need to do some current testings, but i am guessing these saves quite a bit based on the amount of heat the stock setup puts out. Another tip.... When using the IRF9Z34N as the column driver, you can use about any weenie NPN transistor for the predriver, like 2n3904.

I have bulk quantity of IRF9Z34N at good prices.
http://nvram.weebly.com/transistors.html

Thanks Chris. That is a board you once touched also. It is in Silverunicorn's old Hyperball I own.

Same board pictured in the Hyperball section of pinwiki. It's a celebrity.

Thanks Barak I saw those a week or so back. You be getting an order from me when I get some free time.

do they make LED ghosting any worse? or is it the same?
is there any reason why a 0 ohm resistor can't be used in place of the wire jumper (like when removing the diodes from a WPC95 G.I. section on the power driver board, 0 ohm resistors were used in factory modded boards)

It is the same. Your not changing any timing. The only way to fix ghosting is you use a LED OCD or Ghostbuster LEDS and/or patching the firmware to change the scan delay in the matrix. (For the later you will have to do some Googling, it is not obvious, you would need a burner and it's not always effective).

No reason. The 'gap' left by the resistor is a bit large so a 0 ohm would/could look weak and funny. Purely aesthetics.

And, zero ohm resistors don't have insulated leads. In this case it might not matter, but generally, long, bare leads are not a good thing.
--
Chris Hibler - CARGPB #31
http://www.Team-EM.com
http://webpages.charter.net/chibler/Pinball/index.htm
http://www.PinWiki.com - The Place to go for Pinball Repair Info

The heat scales off the solder mask around the column traces. With long not insulated leads you risk shorting between column drivers. I have used heat shrink tube cut in lengths just right. I have also tried using electrical tape to cover the column traces. Using insulated stranded wire *neatly* cut into same length pieces is probably ideal.

Andrew

thanks, i just find using wires look like the board has been hacked, that's just my opinion, i always try and make my repairs look as neat as possible, i'm not saying there is anything wrong with the photo shown with the wires above, they have been done neatly.
Any time i have to use a wire on a board for a jumper i use a dark green wire close as i can get to the color of the board, they look less out of place

Curious, why pull the 27 ohm resistors and replace with a zero ohm jumper?
The FET has a miniscule gate current so a 27 ohm resistor should have very little affect on the circuit. Wouldn't it look better having 27 ohm resistors instead of the jumpers? Unless, of course, the 27's are toasty.

Dammit! Hit quote instead of edit!

It is just because of aesthetics. These resistor get heat damaged, brown, burnt etc...

If I am selling a PCB on this forum. Someone will more likely buy it if it looks clean, etc.. If it has the burn looking resistors, harder sell. Plus if the resistors are replaced with zero ohm someone may go "oh neat, it is upgraded to mosfets" by visual cue alone.

+1. Otherwise if they just see the resistors, they will could look at the manual/prints and go 'Oh yes, TIP42, got one right here."

I disagree on the last point. Use solid core copper wire. It is the ideal solution for this application. A tad more expensive, but worth it IMHO.

You can leave them in place BUT... why risk a resistor on the brink of failure due to the crazy amount of heat that these take, after being powered on for 1,000's of hours? The long and short of the upgrade: you don't need the component any longer. Removing it leaves one LESS thing to fail. This is the signature of any good electrical design.

You answered your own question!

I use zero ohms. Have never had a problem.

I've also done plenty of boards with SQT resistors from Ed - they have the little 'feet' on them that lift them above the surface of the board to allow for a bit of cooling.

20151111_104206.jpgWhat temperature? This modded F -14 came in today for repair.

its a hover craft with all those fans going

Heh, what are those fans cooling anyway?

answer = nothing

Just blowing dust from the cabinet up onto the PCBs.

I don't think it is smart to add a fan to any older game in the backbox. You will probably just suck in more dust.

I bought a game with fans installed venting the backbox - and it had just sucked in more dirt. Agreed.

But you got to love the creative use of the glue gun.

With the angle, it appears they were trying to keep the plasma displays cooled down.

Thanks for sharing and I look forward to trying this upgrade.

Or plasma injectors.

Here is a Pinbot that will be running a lot cooler on location now, thanks to Andrew's (barakandl ) great deal on 40 pcs of IRF9Z34N. Only $4.20 to do 1 game.Pinbot_MosFet.JPG

Thanks Andrew for the fast shipping and great price!

Now, I just need to do my F14 and Earthshaker.......

Nice! Happy to hear they made it and you got them installed. I wonder how long it will take before $4.20 is saved from the utility bill with the reduction of power consumption.

Thanks for the reminder, Andrew you have my replenishment order in your in basket.