Introduction: Williams WPC / Sys11 - Pinball RAM Extraction, and Socket / NVram Installation Without an Electric Desoldering Vacuum

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About: Technologist

Having read many horror stories, with regard to installing NVRam in a Williams WPC pinball machine, I was a bit worried to say the least. It _IS_ daunting, as the traces are small, and often getting nice clean holes so that a socket may be properly installed can be quite difficult without clean chip removal.

At the same time, I REALLY wanted to do this myself.. but just do not have a budget for a proper eletric desoldering vacuum. If you have access to a nice desoldering tool, then certainly, use this.. it is the optimal tool for the job :).

My thought was to employ some of what I had learned, working with old XBOX and Playstation console modifications to this daunting pinball board task.

I am pleased to report success on this, and hope that this information may be beneficial to others who enjoy working on their own pinball machines (which for me is a huge part of the hobby).

Please note that this technique should be somewhat universal for any case where you would like to cleanly remove an IC for socket replacement. In the context of NVRam installation, this is only really required for Williams / WPC machines, where-as, earlier Stern and Bally machines mostly already have the ram on the socket for easy removal and replacement.

Please also forgive the mash-up of photos, I just completed this process on a High Speed, Pin-bot, Demolition man and Star Trek TNG pinball machine, taking photos as I went along, in the hopes that I would have some success to report using this method :)

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DISCLAIMER!!!

Please do proceed at your own risk. Despite my success, and hope that this will enable others to do this without the best tool for the job, it is still a perilous process if you are not careful, you could cause irreperable damage to your MPU board, which in this case could equal BIG BUCKS for a replacement.

For this task, you really need to be proficient and steady with a soldering iron

Supplies

  • Temperature adjustable soldering iron with a small _clean_ tip
  • Heat gun
  • Kapton tape (pref), but could try aluminum foil in a pinch
  • Optional, liquid flux, flux, etc.

Step 1: Board Removal

Remove the MPU from the machine, in the case of WPC based machines, this seems to be a matter of loosening the mounting screws, disconnecting all cables, and then you may push the board upward and it should come out without removing the screws entirely. With older Sys11 machines, you will likely need to depress the backtabs and unscrew where applicable. Most cable connectors will be keyed, however do take photos of the locations of each cable, and consider marking each cable to the corresponding socket on the board to ensure everything goes back correctly.

Find a nice clean area / surface to work on the board. The surface may get damaged here, so don't do this in the dining room unless you have a nice big mat to work on :).

Also consider that you will be melting solder, so consider a filter / vent, and clean airflow to this space.

Step 2: Prepare the Board / Kapton Tape / Foil

In my case, I had this handy roll of kapton tape available. This tape can withstand high temperatures above the melting point of solder, so I figured it would be easy to work with.

In the past I have also used aluminum foil, but in the case of the tape it was sensible to put it on at this stage.. for foil, I would put that on at a later stage which I will mention at that point.

For now, if you have tape like this, apply it sparingly, and cover the immediate regions beside the solder points on the back of the board.

Triple check your location behind the RAM you are attempting to remove!!!!

Step 3: Flux

As these are old boards, flux is never a bad idea to help things melt at a lower temperature.

I have this old gummy flux, but mixing it with a bit of alchohol gives it a nice more liquid consistency to apply. If you have nice liquid or gel flux, more power to you. Just apply it now.

Step 4: Heat Your Irons!

Start with using whatever method you are most comfortable with. In my case, I used one of the old manual spring suctions and kept my iron temp low at about 190c or so, methodically going through each leg hole from the chip, and getting a good amount of solder removal, so I could see a gap in there. Keep going through each leg.. when it seems ok, hold the board up to the light.. and make sure you can see a bit of light bleeding through each hole.. you can never get this 100%, but we are just aiming for a small gap here as a start.

Also, Ensure legs are as straight as possible. If any are bent, you may need to heat them slightly and bend them away from the through-hole.

Step 5: Fire Your Heat Gun

This is really the key step here... and it is this step where most mortals would cause the irreparable damage.

If you are not a Kapton tape person, but want to try aluminum foil, here is your point of entry. Basically, the techinique will be to fold and cut / create a mask out of the aluminum foil which will resemble the mask I have made with the Kapton tape in the photo. The idea is to shield all other parts of the board which would be affected by the heat from ther gun.


Heat the gun, a good rule of thumb is to see how long it takes to liquify a small piece of solder from it.. you want it to just be hot enough for this optimally.. but also anywhere under 200c or so should be ok.

Once the mask is in place, we are going to work with the board (solder side up). Use the heat gun to evenly heat the holes/legs of the ram, ensure the mask is in place and deflecting air from other sensitive areas.

Once the area has reach temperature, depending on how straight the legs are, the chip may just start to drop out, or you may need to give it a very slight amount of force and it should start to come out. If not, then go back to the soldering iron step and try to straighten any bent legs, or suck more solder out of any holes that might again be clogged from the heat gun reflow.

Eventually, the ram should come out with a slightly amount of pressure, at which point you can wiggle it slightly as needed. Slight is really the key word here.. these trace holes are very small, so basically, if you apply enough force to break a small thread, then that is likely enough force to break this trace if it is not coming out cleanly!

Step 6: Socket and Done

Since you removed the ram cleanly, you will have the luxury of nice clean holes.. if not, a quick once over with your prefered solder removal method should work. Clear out the holes, and solder in a applicable row of SIP socket, and plug your NVRam board into this.

Reverse your MPU removal steps, and fire up your game to test your new battery-less operation.