Commodore Plus/4

[centrespot]

Hi All
Does anyone have any idea why my plus/4 has double dots on the screen (see photo)
Thanks in advance

[merman]

That's either a power supply problem or an issue with the main TED chip.

[dimebag]

Hello

I guess memory error...

Do you have stange txt behavior on theses positions ?

Cheers

Laurent

[centrespot]

Hello

I guess memory error...

Do you have stange txt behavior on theses positions ?

Cheers

Laurent

Hi Laurent
Yes the text alters, an S becomes a Q or an F becomes a D
Cheers
Frank

[egel]

Not double quotes?

" " 0x20 00100000
""" Ox22 00100010

"S" 0x53 01010011
"Q" 0x51 01010001

"F" 0x46 01000110
"D" 0x44 01000100

Looks like an error in the same bit

[centrespot]

Not double quotes?

" " 0x20 00100000
""" Ox22 00100010

"S" 0x53 01010011
"Q" 0x51 01010001

"F" 0x46 01000110
"D" 0x44 01000100

Looks like an error in the same bit

So would that mean chip U17 is suspect ?

[dimebag]

Hi

I think it's easy to spot.
The top left character is located at adresse $0400
Two bytes by char (petscii value, then color)

Cheers

Laurent