Backside Socket for 604 Cards

The 604 cards use half size metal can oscillators, and these are not always the easiest to come by. Even when they are it is often easier to install a socket so you can try several oscillators, and unfortunately the giant heatsink will be in the way. Here are instructions for installing a socket on the backside of the card where there is plenty of space.

Because the socket will be on the back side of the card you will need to cross some wires. If you just install an oscillator on the back it will not work, and might fry something. You do not need to remove the existing oscillator as it is an Output Enable oscillator and can be disabled with a jumper wire between pins 3 and 5 (or 1 and 2) (depends on your numbering scheme). So here is what you do:

Take a 14 pin socket and remove pins 1,2,4,6,7,8,9,11,13, and 14 and solder the remaining pins, 3,5,10,12 into the back of the board. Make sure the notch in the socket faces the same direction as the dot on the oscillator on the other side.

Take another 14 pin socket and remove pins 1,2,4,6,9,11, and 13.

Now connect a jumper wire between pins 3, 5, and 7 and another between 8 and 12 and another between 10 and 14.

When you connect them, do the soldering on the bottom of the socket, but do it near the plastic, not on the tips of the pins.

Now when you plug it into the first socket (the one that just has the four pins and is soldered in) it will be an adapter than flips things around, and lets you use a full size can (14 pin package) from the back. Only full size oscillators will work with this design.

The jumper between pins 3 and 5 disable the onboard oscillator, and then the jumper to 7 provides a ground for the new oscillator.

The jumpers on the other side provide power and output the signal.

Please let me know how this works if you give it a shot.

Marc Schrier