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bettablue
June 5th, 2011, 09:30 AM
I keep going back and forth about this damed expansion unit. I think I'm even driving myself crazy.

OK, I have access to the transmitter and receiver cards, a IAC 6-Slot ISA Backplane APSL06 I found on E-Bay, XT case with power supply and cable to connect the transmitter and receiver. I BELIEVE the only things I need to finish the build will be a hard drive and controller. Those I have access to as well. The back plane is a simple pass through unit. Is this all I need to get to complete the build?

I there is nothing more, I'm going to start collecting the parts. :crazy:

eeguru
June 5th, 2011, 09:34 AM
I think so. You might have trouble with cards that use the 14.318 MHz OSC pin in the expansion chassis. I believe the 5161 provided it local on it's back-plane. The one you found on eBay does not. That's probably a rare occurrence though.

per
June 5th, 2011, 11:38 AM
You might have trouble with cards that use the 14.318 MHz OSC pin in the expansion chassis. I believe the 5161 provided it local on it's back-plane. The one you found on eBay does not. That's probably a rare occurrence though.

That's correct. It's actually just an Intel 8284, a crystal and a trim-capacitor. It's fully possible (and not too difficult either) to hack in a regular all-in-one oscillator-can of the right frequency on the APSL06 backplane.

As mentioned, only some cards use the OSC signal anyways.

bettablue
June 6th, 2011, 06:39 AM
This is great info... Can you point me to the correct back plane? I really do want to get this thing working without too much fiddling with one component. I know the entire project has the possibility of failure, so getting the "right" hardware is a must in order to have a better chance of succeeding

Thanks everyone.


I think so. You might have trouble with cards that use the 14.318 MHz OSC pin in the expansion chassis. I believe the 5161 provided it local on it's back-plane. The one you found on eBay does not. That's probably a rare occurrence though.

eeguru
June 6th, 2011, 07:04 AM
The only correct back-plane is the one from the 5161 itself I'm afraid. Most back-planes are just 62 traces chained down the board from slot to slot. I wouldn't let the 14.318 MHz signal prevent you from trying it. There's an extremely high probably the hard drive controller you are wanting to put in the expansion doesn't rely on it sourced from ISA. I recall a lot of early clones either didn't provide it or sourced the wrong frequency anyway. And it's never guaranteed to be phase locked with anything on the bus. That's why most cards that could make use of it don't. It's absence isn't going to damage anything if the controller does need it.