I’ve been trying to bring back a Jungle Lord after 20 years in a barn.
Power supply, cpu and driverboard have been rebuild and are working.
Next up is getting the displays to work properly.
They were showing garbage, some blank, some missing digits, some overly bright digits
On the Master display board I started by removing all the ICs and placing new component back in sockets.
The more rare UDN chips I desoldered and placed back in sockets so I could move them around to troubleshoot.
The resistors measured ok so I didn’t replace.
This gave me an improvement but still not 100% success.
The 100.000 digit on P1 and P3 display is overly bright.
P2 and the two ‘match’ digits on the credits/match display are blank.
P4 and ‘credit’ digits of credits/match are ok
If I connect P1 and P3 displays flatcables only partially so that the last 2 pins don’t make contact (100.000 digit),
then P2 display and the two ‘match’-digits come back and work as also the P1 and P3 display (minus the one digits that are not connected )
If I disconnect wire 7 from the 4J5 connector on the MDB. Strobe 3 the 100.000’s on P1/P3
Now if I let the flatcable for P3 display make full contact all is ok (minus the 100.000)
But if I do the same on the P1 display The bright 100.000 digit is back on P1
And the display is dragging P2 and Mach digits down.
I’ve swapped P1 and P4 displays and the bright digit does not follow
Swapped UDN driver chips and the problem always remains P1/P3
So I’m guessing something on the MDB is shorted and driving the P1 100.000 digit even
though the strobe 3 wire is disconnected.
Anyone have any ideas on where I should look next?