Multiplier Quick Change Block Construction by Ed Nye

I constructed this block for my 6400, but I think it could be used on any Mac with the same multiplier switch configuration. Study the information at; The 6400 Zone (, The Clock chipping Home Page (, my, "6400 Results"( Get all the materials you will need before you start. You can probably get everything from Radio Shack, or else do what I did, and cannibalize what ever decaying electrical stuff you have laying around.

This shows the block with a resistor in the R-145 Position (4.5x)
The resistors are a real "Mac"-Gyver, but they work pretty well.

I installed staples (cut in half) into the block and soldiered the resistors across them. Then I used low temperature, hot glue to give them rigidity.
* The old style resistor with a wire out of each end would probably be a time saver and a good substitute.

Shows the resistors, and block assembly before installation

Three resistors are enough to cover all of the possible multiplier settings. My board requires 1k resistors and the reading across the block without a resistor installed is between 5 and 7K, at each of the four positions. This is different from the listed resistance's at the 64xx at (On Takashi Imai's site) ( You should check the resistance on your board and stay consistent with what ever it is.

* A Cordless Phones is a good source for resistors if you need any.
I used an old ( mid 90's) AT&T. The resistors are green and marked "102", just like the 6400 mother board. It wouldn't hurt to have some spares in case you loose or damage one.
* The two prong crystals from the phone and base are around 40 MHz and will also work on your board. Not much to gain from that, but it is nice to know.
Good luck
Ed Nye