Hi,

Some time ago I made a Bally MPU tester for MPU 35 and MPU 17.
It can be helpful for repairing locked Bally MPU's

It is made of commodity stuff like: resistors, dupont wires , arduino mega, and a “led and key” module which can be bought from various sources.
Hopefully it can be of use to other people for repairing Bally MPU's

It is on github: https://github.com/rdrdphi/bally-MPU-tester

Functions of the tester:

•Do advanced continuity check of :

o The mc6800 socket
o The two pia sockets
o The mc6810 socket
o The 5101 socket
o The U2 eprom socket
o The U6 eprom socket

•Simple logic analyzer function to check the startup via a (time and state with mnemonics ). Sampling rates approx 500ns.

•Test correct operation of and clock generation Phi2

•Test ram chips U7 (MC6810), U8 (5101)

•Test display interrupt generator (U12)

•Check the various logic gates IC’s:

o U14 : CD4049
o U15 : MC3459L=7437
o U16 : 9602
o U17 : 74L00N
o U18 : CD4049
o U19 : CD 4011

•Hardware Self-test J5 (check correct wiring of the tester is correct)

•Check for stuck data bits

Kind regards,
Andre

frontend (resized).jpg

tester_1 (resized).jpg

continu_tester (resized).jpg

Hi,

Thank you for the feedback.
I keep learning about the bally boards.
I changed it in the manual (and in the arduino software).

The smaller Arduino Mega 2560 Pro could also be used i think. I see no reason why i could not be used.

The reason I used the Arduino MEGA 2560 is that I had used it on other projects and reused the hardware, and I like the output pinning arangement.

about the Resistor Wattage:

The resistors are to protect the arduino and the MPU in case of a short on the MPU or the arduino shield.
resistors of 1/4 Watt will be sufficient.

Good question. I did not uniform the resistor valeus after I was done with the project. For the manual I just wrote down the resistors that I used. Not thinking about why I used that value at that time.

Using 330 in stead of the 340ohm and 390ohm will also work.
Using 300 in stead of the 340ohm and 390ohm will also work.

The "low" value of 300ohm valeus for the datalines are needed, because the datalines have pullups of 3.6k.