BJL For Dummies

You need :

- an EPROM type 27c010 or 27c1001 (this is 128K x 8)

- a 32pin socket

- a SPDT switch ( on-on )

- two 4k7 resistors (1/4W)

Where to get the stuff.

Best Electronics

First thing you have to do is to open the Jaguar up and remeve the shield.

After that, you need to cut (or desolder if you can) pin 22. you need to solder a 32 pin chip socket directly on top of your Jag rom bending pin 22 on the socket out as well.

Solder all pins on the socket to the coresponding pins on the rom chip on the jag motherboard. This is time consuming and can be a real trick if you don't have much soldering experience.

Solder one of the ends of the resistor wire to pin 22 on the socket. Solder the other resistor to pin 22 of the rom attached to the motherboard. You will now have 2 resistors poking straight out from the sides of the rom socket assembley one attached to the socket and the other to the rom chip . Make sure that no solder is touching between pin 22 of the socket and the rom to short circut things.

Now solder the wire ends of the resistors together past the resistor portion on the wire.

Now carefully bend the wires towards the top of the chip to not break the solder welds you just made. The ends of the restistors you just soldered together, solder them to pin 32 on the socket/ rom assembley(don't cut them).

Now get 3 wires and solder them to a single pole/dual throw (spdt) on/on type switch. Give yourself at least 4-6" of wire on each lead(preferably 8" on the center lead).

Strip the ends of the wires and solder each outside wire to the pin 22 side of the resistors and put a small piece of eletrical tape between the resistors so the wires wont short together.

Now take the center wire on the switch and solder it to pin 22 on the bottom of the motherboard. This will complete the switch assembley. Put eletrical tape on the shielding to prevent the wires from touching the metal shielding.

What you need is to buy a blank eprom chip from an eletronics supply house (type 27C010 or 27C1001 they are functionally the same). Now copy the debjag.img file to a floppy and take the floppy and the chip to someone with an eprom programmer(examples of people who may have them: computer repair shops, custom pcb board designers, computer science labs in a colege, etc.) or look up eletronc research and design on your local phone book.

Take the file to them and have them program the file on the front end of memory on the chip, or do it yourself if you have access to an eprom programmer. Tell them to program (burn) the file on the chip using a binary format(the only one that works) they will probably charge you 10 to 20 dollars to do this for you.

Now cover the glass window on the top of the chip with black tape (paper tape is best) if you don't, there is a chance the chips will erase (UV light will erase these chips if exposed for a length of time, i.e. don't leave them out in the sun).

Now plug the chip into the socket matching up pin 1 to pin 1 on the jag rom chip(notches on top).

You are now ready to roll!!! The switch now controls whenter you are in debug mode or normal mode.

Prepare the Cable. Look at the diagram. The link to it is located at the main page of JagRealm's BJL page.

Good luck!!!

-Big Dave