The T6A49A, exclusive to an early variant of the TI-81, behaves identically to the later T6A43 in most tests (see below for a difference). Here, I transplant the pin-compatible T6A49A to the TI-86, just because.
https://imgur.com/vdc2CJI
I later removed the yellow capacitor, and the overclock worked reliably.
If you look closely, I lifted one of the pads. Luckily, that was one of the four (!) unused pins. Probably should have practiced a bit more to not burn the board, but everything worked out nonetheless.
Functions that the T6A49A never carried out in the TI-81 do function on the TI-86
-Linking woks as usual
-With the backup battery, memory contents are retained after removing main batteries
-All ~96kb of user-accessible memory is usable as usual
I have yet to confirm that the low battery detection works. A set of batteries that triggered the low battery message in a TI-83+SE did not do the same in this TI-86.
BZ80TEST returns these results:
Test Version: 7
SLL Exists: 1
DAA Internal Carry: 1
MLT HL Missing: 1
RLD Uses A for Flags: 1
Flag b3 Settable: 1
Flag b5 Settable: 1
SCF/SCF AND b3/5 Set: 1
SCF/SCF AND b3/5 Clr: 1
NOP/SCF ORs Flag b3: 1
NOP/SCF ORs Flag b5: 0 <-- This would have been 1 with a T6A43
Undoc. NEG Works: 1
Interrupt Detect Bug: 1
Port $15 ASIC ID: 0
LCD Delay: 1
New Kinpo LCD: 0
LCD VRAM Width: 0
Port $14 Mirrors $04: 1
A variety of programs worked as expected:
-Finance and Inferential Stats packages
-TI-86 Demo
-pterodactyl (memory expander)
-ztetris
-Fonts
Things working pretty much as usual:
https://imgur.com/a/sPowIVI
Someday I'll try this out again, but with the T6A49. Feel free to suggest any further tests
https://imgur.com/vdc2CJI
I later removed the yellow capacitor, and the overclock worked reliably.
If you look closely, I lifted one of the pads. Luckily, that was one of the four (!) unused pins. Probably should have practiced a bit more to not burn the board, but everything worked out nonetheless.
Functions that the T6A49A never carried out in the TI-81 do function on the TI-86
-Linking woks as usual
-With the backup battery, memory contents are retained after removing main batteries
-All ~96kb of user-accessible memory is usable as usual
I have yet to confirm that the low battery detection works. A set of batteries that triggered the low battery message in a TI-83+SE did not do the same in this TI-86.
BZ80TEST returns these results:
Test Version: 7
SLL Exists: 1
DAA Internal Carry: 1
MLT HL Missing: 1
RLD Uses A for Flags: 1
Flag b3 Settable: 1
Flag b5 Settable: 1
SCF/SCF AND b3/5 Set: 1
SCF/SCF AND b3/5 Clr: 1
NOP/SCF ORs Flag b3: 1
NOP/SCF ORs Flag b5: 0 <-- This would have been 1 with a T6A43
Undoc. NEG Works: 1
Interrupt Detect Bug: 1
Port $15 ASIC ID: 0
LCD Delay: 1
New Kinpo LCD: 0
LCD VRAM Width: 0
Port $14 Mirrors $04: 1
A variety of programs worked as expected:
-Finance and Inferential Stats packages
-TI-86 Demo
-pterodactyl (memory expander)
-ztetris
-Fonts
Things working pretty much as usual:
https://imgur.com/a/sPowIVI
Someday I'll try this out again, but with the T6A49. Feel free to suggest any further tests
