Re: HELP with UniDisk 3.5'

[Wayne Stewart <waynes@intergate.bc.ca>]

Lancyne Cel�r wrote:

>         Hi all on the CSA2!
>
>         Recently I acquired a super-used ][c (the fourth now) that came to me with two
> Unidisks. It was taken from an office (its user used to smoke while working -
> there was a mess of ashes inside the keyboard and the case).
>         The good new is that it has the new roms, even if the motherboard is older than
> the other I got. The bad news are that the machine is somehow corrupted inside.
>         When in 80-col mode it shows some " flickering on the screen, in HGR some
> pixels remains lightened and it refuses nine times on ten to load prodos. When I
> try to reboot (warm or cold) the machine, with prodos the message is
> *relocation/configuration error* and it hangs up, with or without unidisk
> connected, even with the 3.5' as boot. The few times it started with diskware
> 1.1 (you know where can I download a newer version? this doesn't recognize my
> ][c, he sez it's a ][e...) I have rightly formatted a 3.5' and putted prodos on
> it. When I reset it with open-close apple-ctrl-reset it shows the message "RAM
> 0010000", perhups with some 0 more or less. My other ][c's keep happily joking
> with HGR when I do it them.
>
>         Any of you know what this could be? Some memory chip gone?

On the self test that's the code for a bad RAM chip. I don't recall whether 00100000
would indicate the 3rd chip from the front or rear of the machine. The IIc had a
tendency for bad RAM.

>
>         Do you know what is the ROM that allows 3.5's use?

It's the one labeled MON. At the center of the board, at the front by the speaker
plug

> I think I've recognized it,
> it's the only dated 1985, unlike the other dated 1982/83, like my others ][c
> have. I've seen that W1 and W2 have been manipulated on the mobo, it's perhups
> to allow the ROM to work?

The UniDisk ROM is a higher capacity eprom so W1 & W2 allowed you to make
this change

> Should I change the ROMS? How?

If you only have one functioning IIc then it'd be nice for it to have the UniDisk
ROM. Carefully pry out the MON with a small screwdriver and swap them.
You've noticed the W1 W2 mod so make the mod on one machine and reverse
it on the other