Z80 ERROR: Difference between revisions

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The {{Chipname|68k}} didn't receive a reply to command $01 from the {{Chipname|Z80}} in time. The Z80 doesn't test the [[SM1]] ROM, its [[Z80 RAM|RAM]] nor the {{Chipname|YM2610}} but if any of those components are bad, they can prevent the Z80 from being able to reply which will then cause the error.
The {{Chipname|68k}} didn't receive a reply to command $01 from the {{Chipname|Z80}} in time. The Z80 doesn't test the [[SM1]] ROM, its [[Z80 RAM|RAM]] nor the {{Chipname|YM2610}} but if any of those components are bad, they can prevent the Z80 from being able to reply which will then cause the error.


=Suggestions=
=Repair suggestions=


* Check Z80 power, reset and [[clock]] signals
On [[MV1F]] boards, this error seems common due to trace cuts caused by a [[corrosion|leaking battery]]. A few [[trace patching|wires]] can solve the problem.
* Check Z80 work RAM
 
* Check Z80 +5V supply, reset and [[clock]] signals
* Check connectivity to Z80 work RAM
* Check connectivity to SM1 ROM or cartridge's M1 ROM
* Check {{Chipname|NEO-D0}} Z80 control lines
* Check {{Chipname|NEO-D0}} Z80 control lines
* Check Z80 data bus at {{Chipname|NEO-C1}}
* Check Z80 data bus at {{Chipname|NEO-C1}}
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=MV1C=
=MV1C=


The {{PCB|MV1C}} board displays this error with no cart inserted since it has no SM1 ROM. This is normal.
The {{PCB|MV1C}} board displays this error when no cart inserted because it has no SM1 ROM. '''This is normal'''.


[[Category:Audio system]]
[[Category:Audio system]]
[[Category:Repairs]]
[[Category:Repairs]]

Revision as of 04:47, 5 September 2017

Simple as that.

Causes

The 68k didn't receive a reply to command $01 from the Z80 in time. The Z80 doesn't test the SM1 ROM, its RAM nor the YM2610 but if any of those components are bad, they can prevent the Z80 from being able to reply which will then cause the error.

Repair suggestions

On MV1F boards, this error seems common due to trace cuts caused by a leaking battery. A few wires can solve the problem.

  • Check Z80 +5V supply, reset and clock signals
  • Check connectivity to Z80 work RAM
  • Check connectivity to SM1 ROM or cartridge's M1 ROM
  • Check NEO-D0 Z80 control lines
  • Check Z80 data bus at NEO-C1
  • ...

Note: Replacement SMT Z80s can be found in some Ti calculators :)

MV1C

The MV1C board displays this error when no cart inserted because it has no SM1 ROM. This is normal.