• Please review our updated Terms and Rules here

Difficulty with expansion RAM on Baby Blue II multicard

MissArgent

MissArgent

Veteran Member
Joined
Oct 3, 2016
Messages
538
Location
Illinois, USA
So, I'm trying to set up a Baby Blue II IO multicard/Z80 co-processor board I snagged at VCF Midwest back in September. I'm currently trying to rig it to work with my IBM 5155 (256k, motherboard max) to start, but despite the internal diagnostics (TESTBBII.EXE) giving the RAM a pass the PC doesn't seem to see the expansion RAM on the board's banks one to three. My settings gel with what the manual says about configuring SW3, the 192k expansion portion but I get the hunch I may still be missing something. Can I get a second opinion? The XT auto-sizes RAM, so this likely isn't a motherboard dip config issue.

zXZIuAT.png


zh47TnB.jpeg
 
MissArgent said:
I'm currently trying to rig it to work with my IBM 5155 (256k, motherboard max) to start ..
Click to expand...
So, the 5155's motherboard switch settings are set to enable all motherboard RAM. No RAM cards. Without the Baby Blue II fitted, when the POST counts up the RAM at power-on time, you see the POST count up to 256 KB. When you add the Baby Blue II, the 5155 still only counts up to 256 KB. Please confirm all of that.

MissArgent said:
Can I get a second opinion?
Click to expand...
So you want the Baby Blue II's 192 KB of RAM to appear in the motherboard address space of: 256 KB to 448 KB.
The Baby Blue II card's manual indicates that switch bank SW3 (red block at far left) configures the card's RAM.
The photo shows SW3 set as required (all Baby Blue II's three RAM banks populated, and that RAM to start at motherboard address 256 KB).

In case of a problematic switch, try changing each of SW3's switches between ON and OFF a few times. Ideally, the switches in SW3 would be checked using a multimeter (each switch showing 0 ohms when it is in the ON position, and something other than that in the OFF position.)
 
modem7 said:
So, the 5155's motherboard switch settings are set to enable all motherboard RAM. No RAM cards. Without the Baby Blue II fitted, when the POST counts up the RAM at power-on time, you see the POST count up to 256 KB. When you add the Baby Blue II, the 5155 still only counts up to 256 KB. Please confirm all of that.


So you want the Baby Blue II's 192 KB of RAM to appear in the motherboard address space of: 256 KB to 448 KB.
The Baby Blue II card's manual indicates that switch bank SW3 (red block at far left) configures the card's RAM.
The photo shows SW3 set as required (all Baby Blue II's three RAM banks populated, and that RAM to start at motherboard address 256 KB).

In case of a problematic switch, try changing each of SW3's switches between ON and OFF a few times. Ideally, the switches in SW3 would be checked using a multimeter (each switch showing 0 ohms when it is in the ON position, and something other than that in the OFF position.)
Click to expand...
Yup. Motherboard is configured appropriately is normally expanded to 512kb with a Quadboard. The POST RAM count only counts up to 256k with the Baby Blue installed and configured, and the additional RAM is not accounted for by CHKDSK either. SW3 1, 2, 3, and 4 are giving me some resistance (Less than half an ohm in all cases) in spite of being on, so I think that might be the next lead to follow up on. I'll be breaking out the Isopropyl.
 
Last edited:
MissArgent said:
SW3 1, 2, 3, and 4 are giving me some resistance (Less than half an ohm in all cases) in spite of being on, so I think that might be the next lead to follow up on.
Click to expand...
My "0 ohms" should have been "about 0 ohms". Less than half an ohm is okay. For example, the DIP switches on two cards that I checked, showed 0.2 ohms.

Switch 4 on SW3 is OFF for your configuration, and so it is important to verify via the multimeter that, when OFF, it measures significantly more than the ON reading. You are measuring in-circuit, and so the actual reading will depend on the circuitry on the card.
 
Yeah, I was wondering about the II or II Plus thing. The packaging and manual just say "Baby Blue II", no mention of a Plus. Going off this thread, that seems to be normal?

Cleaning the dips didn't do much, but i've got to scoot for work so i'll have to come back to this one later.
 
You must log in or register to reply here.
Back
Top