HX-34 memory upgrade | MSX Resource Center (Page 8/8)

By Manuel

Ascended (19298)

31-12-2020, 15:58

Can someone confirm that the HX-33 is identical to HX-34, except for the missing FDC and disk drive?

@popolon_ Can you run another test program please? You can find it here.

By popolon_

Champion (331)

21-07-2021, 12:10

@Manuel ,I received HX-33, but i do not yet know if it is working. If it works, shuold i dump something?

By Manuel

Ascended (19298)

21-07-2021, 16:03

Please compare it to the HX-33 regarding main board layout etc. There were many photos in this thread.

By popolon_

Champion (331)

25-07-2021, 10:22

Yes, the toshiba HX-33 works.
Anyway toshiba HX-33 and HX-34 have almoust identical IC numbers and chips ( IC1-IC21, IC25-IC41 are exactly same). Only differences are IC22-IC24, IC42-IC59.
IC22(74ALS133), IC24(74LS245) and IC43-IC59 are only in HX-34. IC22+IC43-IC59 are for disk side. IC24 could be for keyboard (at least it goes to front panel side where there is keyboard and joystick and module port).
IC23(74LS145) and IC42(TA75559P) are only in HX-33, and that IC23 shuold be for keyboard BCD.