Model 1 Level 2 screen full of @

[ldkraemer]

Dokken,
Do you know if your Model 1 has ROM Ver 1.1 or Ver 1.3?

What is the Signon Message R/S or Radio Shack?

I sure wish Someone would loan out that EPROM EMULATOR. That would make this easy.

Larry

 

[Dokken]

this crusty, rusty model 1 has the 3 chip rom board.

I'll dig out my romulator z-80 and programmer today. there's a model 1 diagnostic rom on GitHub, or what roms would you recommend loading?

 

[ldkraemer]

Well, the ROM Version 1.3 has some updates for Keyboard debounce and some
updated cassette load code so the cassettes load better/easier.

But, why I asked we can make a boot ROM that writes a 0x00 to port 0xFF,
puts characters on the screen so you can determine if 32 or 64 are on the display.
and loop. This will allow you to troubleshoot port 0xFF and track what is missing
for the MODESEL Signal.

Larry

 

[ldkraemer]

Model 1 Level 1
Z33 ROMA MM2716E 4K Part Number 3108011
Z34 ROMB MM2716E 4K Part Number 3108012

Model 1 Level 2
Z1 ROMA MM2716E 4K Part Number 3108013
Z2 ROMB MM2716E 4K Part Number 3108014
Z3 ROMC MM2716E 4K Part Number 3108015

Model 1 Level 2 Mother Board Revision G - 2 ROM Set
Z33 ROMA&B 8044364 8K Part Number 7807
Z34 ROMC 8044732 4K Part Number 7804

Model 1 Level 2 Mother Board Revision G - Single ROM
Z33 ROM 8044364 12K Part Number 7809 BASIC I


The model 4 contains 14K of ROM (in Model III Mode) divided into:
U68 ROMA MCM68A364 8K Part Number 8048364 0000-1FFF = 8192
U69 ROMB MCM68A332 4K Part Number 8040332 2000-2FFF = 4096
U70 ROMC MCM68A316 2K Part Number 8042316 3000-37FF = 2048 less 37E8-37E9 = 0xFF



Larry

 

[Dokken]

had to take a break on this one, but I did isolate the offending chip and have it able to boot now! It was a 367. I burned the diagnostic rom and am making progress but I may still have a couple of bad ram chips. I have another non-working model 1 that I plan to torture myself with soon.

thanks for everyone's help!