Leon Borre U16 9602 Conversion to 6802

Bally, substitute the obsolete oscillator 9602 (U16)

The last years it is almost impossible to find the IC 9602 used as clock generator. This solution as been created by David Wallerich from France, and this article is a free adaption of his solution.

We will use a CPU chip 6802 instead of the original 6800 for two reasons; we can easily install a new clock circuit for this IC and the 6802 has some internal memory on board , which we can use instead of the memory chip 6810 on the board.

Material.

What do we need , only two resistors , two capacitors and a crystal, which is not critical, any crystal having a frequency between 1,5 and 2 Mhz is ok..The only more elaborated thing is an adapter printed circuit.You can order this printed circuit and the parts at electro_wall_2000@yahoo.fr

What we need... a cristal, two condensers of 27pF, resistors of 3,3 and 4,7 Kohm, and of course a 6802 cpu chip.

Schematic.

This is the schematic with the changes applied when using a 6802. Whenever you mount this without using an adapter circuit board, bend pins 39, 38, 37, 36, 35 and 3 upward to solder the components on these pins , pin 8 must stay inserted as the 5 volts arrives at that pin and we still need that.

The changes made with the use of an adapter board. Only one wire to solder on pin 5 of IC U16, see text below.

Blue arrow indicates removed 6810 U7, Orange arrow where the cut is to be made if you do not remove U16.( see text)

The 9602 not only delivers a clock to the cpu but also at different places on the board. The start of his syncronisation signal, named Q2, is at pin 5 of U15. The output now coming from pin 37 of the 6802 will therefore be connected to this pin. Of course we need to remove the old arrival of the Q2 signal. two possibilities , you remove the bad 9602 U16 , or let it in place and cut the run between pin 10 of the U16 and pin 5 of U15.

Attention !!

Do not forget to remove the 6810 U7 from the CPU board!!