Trying to reverse engineer Tennokoe bank 2, picture detail and need help IDing parts

I asked in different subforum section but there hasn't been any response yet and I dunno if anyone still pay attention to PCE/TG16 section so I'd ask here.

This is what I have:



I'm still drawing up schematic. This is what I found out: A2 to A10 are connected from EXT port to both Hudson chip and SRAM, A0 from ext seems to only connect to Hudson chip, giving me the impression that only Hudson chip is handling A0 on SRAM separate from PCE. A1 on EXT is NOT connected to anything which seemed a bit odd. Maybe the EXT pinout info I got is wrong?

Data D0-D7 only goes to Hudson chip, and they are separate from another set of D0-D7 between Hudson chip and SRAM, probably to handle tristating when SRAM is not needed? SRAM does have its own /OE and /CE so dunno why.

Anyway, I'd like to know the pinout or basic detail of the 3 unknown transistor style parts. I have the original image unedited and original image in photoshop format with separate layers in case I need to make correction or revisions. There's type error in the not on bottom right, missing an 'e' and a space. Also I forgot to mark T1 on the picture above but it is known transistor, a 2SC3330 planar epitaxial transistor and I have marked C, B, and E above.

If someone can figure out that Hudson chip, maybe it'd be possible to change the SRAM to something bigger like 8kB (64x8). The SRAM can defiantly be replaced with something much smaller and if someone is willing, desolder and remove the Hudson chip, hack it into TurboExpress with a SMD sized SRAM chip. Is there even room for this anyway? :biggrin-new:

 

Probably something to do with the fact your picture doesnt work on the other thread.

Duplicate posting isnt going to do you any favours with the mods though.

 

Maybe something in here will help, http://www.pcenginefx.com/forums/index.php?topic=16879.0