clueless_engineer (Brett)
Experienced Member
Hello,
I'm working on a water damaged Sharp MZ-80B. Quite a neat machine. Having the service manual is a great help as well.
It came with 64KB of system RAM (base 32KB plus 32KB expansion board), otherwise it's stock (8KB graphics RAM, no expansion bay unit).
I am documenting what I can also on my Github as I know websites can sometimes disappear. I also have one YouTube video at the moment - working on the keyboard presently (Part 2).
There was a bit of water damage on my board that I've hopefully fixed ... will know when I get replacement parts (Z80-PIO, 8253, 8255).
The machine also has three custom gate arrays ... they look okay ... fingers crossed.
The Service Manual mentions a RAM CHECKER ROM that can be used - I've not found it online so I'm guessing it's not available anywhere. Just thought I'd put this post here in case.
Insert RAM CHECKER into BOOT ROM socket and turn the power on. Then RAM TEST-1 and RAM TEST-2 will automatically be carried out from RAM address $0000 to address $FFFF as shown below and the tested results will be displayed.
The checker tests the store by dividing it into two parts of addresses $0000 to $7FFF and $8000 to $FFFF.
1) RAM TEST-1
A write/read test of data $00 and $FF is carried out from address $0000 to $FFFF, and if an error occurs ERROR is displayed in the 16K bytes unit.
An error is displayed by the address number at which the error takes place, and the execution of check is stopped at the address.
2) RAM TEST-2
A write/read test is carried out with the following items:
a) Write-in data $00 (From address $0000 to $7FFF)
b) Write-in data $FF (From address $0000 to $7FFF)
c) Write-in data $00 (From address $7FFF to $0000)
d) Write-in data $FF (From address $7FFF to $0000)
e) Write-in data $FO and $OF entered alternately (From address $0000 to $7FFF and vice versa)
f) Write·in data $00 (From address $8000 to $FFFF)
g) Write-in data $FF (From address $8000 to $FFFF)
h) Write-in data $00 (From address $FFFF to $8000)
i) Write-in data $FF (From address $FFFF to $8000)
j) Write-in data $FO and $OF alternately (From address $8000 to $FFFF and vice versa)
I'm working on a water damaged Sharp MZ-80B. Quite a neat machine. Having the service manual is a great help as well.
It came with 64KB of system RAM (base 32KB plus 32KB expansion board), otherwise it's stock (8KB graphics RAM, no expansion bay unit).
I am documenting what I can also on my Github as I know websites can sometimes disappear. I also have one YouTube video at the moment - working on the keyboard presently (Part 2).
There was a bit of water damage on my board that I've hopefully fixed ... will know when I get replacement parts (Z80-PIO, 8253, 8255).
The machine also has three custom gate arrays ... they look okay ... fingers crossed.
The Service Manual mentions a RAM CHECKER ROM that can be used - I've not found it online so I'm guessing it's not available anywhere. Just thought I'd put this post here in case.
Insert RAM CHECKER into BOOT ROM socket and turn the power on. Then RAM TEST-1 and RAM TEST-2 will automatically be carried out from RAM address $0000 to address $FFFF as shown below and the tested results will be displayed.
The checker tests the store by dividing it into two parts of addresses $0000 to $7FFF and $8000 to $FFFF.
1) RAM TEST-1
A write/read test of data $00 and $FF is carried out from address $0000 to $FFFF, and if an error occurs ERROR is displayed in the 16K bytes unit.
An error is displayed by the address number at which the error takes place, and the execution of check is stopped at the address.
2) RAM TEST-2
A write/read test is carried out with the following items:
a) Write-in data $00 (From address $0000 to $7FFF)
b) Write-in data $FF (From address $0000 to $7FFF)
c) Write-in data $00 (From address $7FFF to $0000)
d) Write-in data $FF (From address $7FFF to $0000)
e) Write-in data $FO and $OF entered alternately (From address $0000 to $7FFF and vice versa)
f) Write·in data $00 (From address $8000 to $FFFF)
g) Write-in data $FF (From address $8000 to $FFFF)
h) Write-in data $00 (From address $FFFF to $8000)
i) Write-in data $FF (From address $FFFF to $8000)
j) Write-in data $FO and $OF alternately (From address $8000 to $FFFF and vice versa)