F4/FMPAC board in an 8280

By mau_rizio

Resident (49)

mau_rizio's picture

01-03-2019, 22:19

Hi guys, i would like to install this board on my 8280 expanded to 2+ but missing the internal FM-PAC and the lovely MSX logo at boot becuase it's missing the F4 latch.
Someone has installed this board in an 8280?
Where i can get the SLTSEL signal? I'm thinking from the 31 slot, but how?
Thank you

Login or register to post comments

By Wild_Penguin

Hero (644)

Wild_Penguin's picture

04-03-2019, 10:02

Hi mau_rizio,

Here we can see the slot map of 8280. You are correct that slot 3 is expanded and subslot 1 is free.

Generally to see where to get the signal, I think the service manual is the best source. Thankfully with these computrers the slot is not only already expanded but the signal is already available at the _MY header! I own an 8255 and have installed MSX-DOS in it, and it was quite straightforward. I believe it is pin 35 (according to many DIY instructions, but didn't check the SM too deeply right now). I haven't had a 8280 but it seems it is similar enough to the 50 and 55. Just double-check the documentation!

As you are installing an fmpac, have you considered how you are going to get the sound out? Mix it with PSGs? These (NMS 82XXs) are notorious for their bad (and even potentially dangerous, if two carts are inserted simultaneously) mixing circuits.