BalCheckHR – New Prototype Hardware for the Astrocade!

Here is the new BalCheckHR hardware for the Bally Arcade/Astrocade that was sent to me by MCM Design a couple of days ago:

board1

This following information is from the preliminary version of the introduction of the BalCheck manual:

“What is it? A factory tester called ‘Balcheck’ (Bally Check), used by the manufacturer around 1980, was utilized to check Bally/Astrocade motherboards. BalcheckHR, providing an upgraded version of Balcheck, will do the same and more.

BalcheckHR is an 8KB package which includes:

  1. Standard and optional Balcheck test routines.
  2. An easier to read Balcheck error report sequence.
  3. A checksum test routine to compute and compare the checksums of 3 on-board
    ROM versions.
  4. Two custom write/read loops for use with a logic analyzer.
  5. Two “crash test” demos that can be used to determine if a motherboard
    will run perfectly for a long period of time.
  6. SetScreen3, a new diagnostic tool, which can help diagnose a failed motherboard
    producing a black (blank) TV screen at power on.
  7. Three user RAM test routines (user must provide a 50 pin ribbon cable adapter).
  8. Three high resolution demos for use on a “modified for hi-res” Bally/Astrocade.
  9. A hi-res screen RAM test routine similar to Balcheck’s low-res screen RAM test
    routine.
  10. SetScreenHR, similar to SetScreen3, can help diagnose a failed “modified for
    hi-res” Bally/Astrocade.

MCM DESIGN’S BALCHECKHR BOARD

This wire wrap board, built by MCM Design, utilizes standard TTL chips and two standard 7-segment displays. Two 74LS374 chips act like output ports, latching in output data and turning on or off the display segments.

This scheme allows custom characters to be displayed typically not possible with specialty LED display drivers or specialty 7-segment displays. This advantage is utilized in the BalcheckHR programming allowing hexadecimal numbers to be displayed. In most cases, the display is easier to read, ie, the user does not have to consult the user manual to look up some display interpretation table.

The board also uses a multi-carted 32KB EEPROM. Any one of four 8KB programmed banks can be selected and executed using a 2 position dip switch and mini-toggle switch. Two banks are programmed with BalcheckHR. The other two banks are programmed with a revised copy of the on-board ROM and a Z80 Check routine, both of which may be used to help diagnose a Zone B motherboard failure, relating to the operation of the Z80 address A0-A15 and data D0-D7 buses.

Here are some more pictures of the hardware sent to me by MCM Designs:

board2

board3

Here are some additional pictures that I took of the unit sent to me:

I’ll be using the BalCheckHR unit and software over the next couple of weeks and reporting about it here.  The manual for this hardware/software combination is about 85 pages long, so testing it out will take some time.  I’ll be posting more information from the manual and perhaps some schematics and other drawing.  Keep an eye out for updates over the next few weeks.

Adam

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