Hello trying to get a c128D up and going again. It will boot to c64 mode, the cart does work. ON power up I get a boarder but no text just blank screen after a flash page of garbage. From ray's repair docs I suspect.
U33 318018-02 C128 BASIC LO ROM
No BASIC startup screen in 128 mode only. Computer goes into
"monitor" mode.
U34 318019-02 C128 BASIC HI ROM
Blank screen with border at 128 mode startup. Lines or "garbage"
inside border.
I have a donor c128 but the do the IC locations equal the same spot on a 128D board? The chip #s are different between the two. I did swap U34 as the board layout and trace that i tested was exact; this gave me a "break error" and some ML code (?) following it when booted instead of the blank screen. I think i am in the right area, suggestions or any info please. Are there bin files and what type prom if they exist could be used to replace these.
I have another working 128D, but dont want to chip swap it with this one as there is some hum in screen and audio of the broken one and I don't want to wreck anything know good. I'll pick up caps and repair supply in the AM>
Thanks
John
Quote from: polishedball on March 08, 2011, 01:20 PMI have a donor c128 but the do the IC locations equal the same spot on a 128D board? The chip #s are different between the two.
Why don't you send an e-mail to Ray Carlsen in order to find out exactly?
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It appears that the chip for basic 7.0 in my 128D has both the high and low in one prom part number basic.318022-02.bin that equals 318018-02+318019-02 this would explain the break I got in the middle when only the low code was present from the swap and not the high.
I have download a bin file for the basic.318022-02.bin any idea what type prom size this burns onto? the factory chip is a MOS and not a prom. I am thinking it is a 27_256 but looking for opinions.
Thanks
:)Repaired :) burning and swapping u34 fixed it up.
Great news! Was it a 27256 or a 27512 that you needed? I can't remember the size of the BASIC ROM.
Quote from: maraud on March 10, 2011, 08:37 AM
Great news! Was it a 27256 or a 27512 that you needed? I can't remember the size of the BASIC ROM.
27256 took care of it.