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| The CoCo 2B Lowercase Mode |
There are two ways to put a CoCo 2 into true lowercase mode. First, identify your CoCo 2. This works only on the
Korean built "B" models (see below for a possible exception. That is, CoCo 2s with a "B" in the catalog number. If you
press the zero key and it has a slash through it, you have a "B" model.
Method One:
POKE 359,57:POKE &HFF22,&H50
This works, but completely disables ASCII saves (SAVE(M) "filename.bas", A). It also disables automatic return to text
screen when in a graphics (PMODE) mode. Gak! Use with caution!
Method Two:
Put the CoCo into 64K mode by copying the ROM to RAM. This should do the job:
10 FOR X=32000 TO 32025:READ A:POKE I,A:NEXT I:EXEC 32000
20 DATA 26,80,142,120,0,236,132
30 DATA 183,255,223,237,129,183
40 DATA 255,222,140,254,255,37
50 DATA 241,183,255,223,28,175,57
Then type one of the following:
POKE &H95C9,&H57:POKE &HFF22, &H50 'produces a green screen w/ green border
POKE &H95C9,&H17:POKE &HFF22,&H10 'produces a green screen w/ black border
POKE &H95C9,&H37:POKE &HFF22,&H30 'produces an "inverse" screen, green on black
CoCo 2s with the "B" in the Cat. No. have true lowercase ability because of their 6847T1 Video Display Unit (VDU).
However, it has been noted by some collectors, including documented at The CoCo Lounge, that not all "B" models
have this capability. In addition, at least one US built model, a 26-3127B, has demonstrated this capability. Bottom
line: The Cat. No. is probably not a reliable indicator of lowercase capability.
When buying with this feature in mind, if possible, ask the seller to do the zero test by hooking up the CoCo and
reporting if there is a slash through the zero. This indicates the presence of the 6847T1 VDU, as opposed to the older
6847 VDU (no slash, looks like a skinny O). The 6847T1 is the chip with true lowercase capability.
In the Dec. 1987 issue of The Rainbow, Marty Goodman, in his CoCo Consultations column, reported that this worked
on the CoCo 2 26-2027B, 3134B, and 3136B. The 3127B wasn't included in the list, but it may not have been in
production at the time of writing. He does reference a 2027B, which is probably a typo. As far as I know, all CoCos
have catalog numbers with the "3" starting the model number, e.g. 26-3xxx. But maybe there is a mysterious
26-2027??? heh!.
At this time, I can not find further documentation or evidence that other "B" model CoCo 2s have this capability. The
only CoCo 2 I have operational at the moment is a Korean 26-3127B and it does have the lowercase ability. If you
have one with a different model number, and it works, please email me at captcpu@clubltdstudios.com and let me know
the model and serial number.
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