Scared Stiff – NVRAM Installation

There are two major benefits of installing NVRAM on games pre Stern’s S.A.M system, which use a different battery type that rarely leaks, those being :

  • Battery Leakage – Older style batteries have had, in the past certainly with careless operators, leak onto the board. Whilst the board can be worked on, and the leakage neutralised to stop any further corrosion, a battery damaged board can throw up problems, as well as expense in resolving the leakage.
  • High Scores – with an NVRAM chip installed, for all intents and purposes, you aren’t going to have any issues going forward with your high scores being lost.

For a more in depth review of NVRAM – you can see my review of NVRAM in general here.

NVRAM location on WPC 95 Games

The first thing that was needed was to remove all of the ribbon cables and connectors onto the MPU. I always take lots of pictures, it’s just good practice even if you are doing this often, another handy tool to use is a Sharpie, as you can quickly write the plug number on the connector itself (i.e. J201) just to make it easier to re-install.

The first thing I do is to remove the battery pack from the socket, it will serve no purpose now and if there is any nasties lurking underneath, such as battery leakage eating away at the board, that can be neutralised at the same time. That just takes six points to desolder and then removal of the pack itself. this can be tricky to remove if you don’t get all of the solder out. Take your time, don’t overheat the board and cause damage and take your time.

Next up is the installation of the NVRAM chip itself, each board will have it’s own location to remove the old chip and reinstall the new. Invariably the supplier of the NVRAM you are buying will be able to tell you and provide the socket location for you to install. Whenever I do any board work, it is good practice to put a socket in. I am very hopeful I will never need to replace this chip, but some chips (such as 74LS374) can go bad through time. Simply adding a socket is a cheap, simple and good practice when doing board work. You can buy runs of the correct pitch sockets which you cut down to the correct socket length so you always have some for the right size.

On this board there were around 14 pins each side to desolder, these boards are expensive to replace so ensure you are comfortable in working on them, I highly recommend a desoldering station, you can set the heat to the correct temperature and you aren’t going to keep the heat on too long to destroy the tracks. A quick nip with the iron, press of the vacuum and the solder should come straight off of the pad. Rinse and repeat.

Reinstallation is simple, I use the old chip as a placeholder in the socket, cut the socket strips to shape, hold the board with a clamp and resolder into place. Usual rules apply for soldering, you want a nice concave clean solder and make sure you drop some down onto both sides of the board. Soldering always feels right when you have done a good job, so you will know.

Once done you can check your work by buzzing out the pins with your multimeter just to be sure, again, if there wasn’t excessive heat, there shouldn’t be any issues – but again good practice to be sure. Reinstall the board and all will be good to go.

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