Power Supplies & Motherboards

[Bruce Graham]

Hi Al;
Looking for some info in the power supplies as they relate to the CPU mother boards;

Looing to upgrade my original Amptron PM9800 MB to the newer Itox CB50-BX MB in the CPU.

Wondering if it is a straight motherboard swap with no changes to the power supplies?

Cheers and thanks for any help and advice!

Bruce
In Canada

[arjepsen]

I haven't messed with the old motherboard, but the newer motherboard can use both the old AT powersupplies (that uses two connectors), and the newer ATX supply.
As far as I know, they consistantly used AT powersupplies in all the d8b cpu units.

I'm uncertain about whether the memory sticks are reusable though.
If they fit in the memory sockets, I believe you should be good to go, by simply taking everything except the cooler and cpu off the the old one, and plug it on the new one.

[Phil.c]

I seem to remember an easy swap between the old and new boards, but a change with the processer.

[Y-my-R]

From the perspective of the PC/AT power supplies, it's a straight swap.

The memory also fits (if the "newer" DIMM banks were used on "old" boards. In fact, I just split up the 256 MB I had in the "newer" board, to keep 128 MB in that one, and put the other 128 MB in an "old board" unit that I'm getting ready. The remaining 128 MB works in each type of board.

The only thing I would not be sure about, is if the posts/risers match between the old and the new mainboard... but I think they should. That's standardized, too.

...and just because I did a full power supply swap just now... there are some component differences in the power supply, such as that the transformer has different numbers stamped on it and looks a little different. Because of this, if you'd ever swap power supply components, I'd recommend to swap them "as a set" to avoid component incompatibilities. But as for as how the PC/AT power supply connects to and works with the motherboard, there's no difference.

(I swapped the AT power supplies between different D8B units a few times in the past and they work in both, newer/older board configurations).

As far as the CPU goes, I'm not sure. The sockets look similar in all 4 D8B rack units I have (2 old board, 2 new board), but I didn't really carefully look at the CPU socket type/number. If that number is the same, the CPU "should" work in the newer board type, too (I don't remember if these boards are THIS old, but you may have to configure the data-bus and clock speed multipliers via jumpers on the mainboard, before you power it on... these things were a bit more cumbersome on old computers like that, when comparing to building a new/modern computer where most of that happens automatically).

Curious why you want to swap out the board, though. Did it go bad?

I used to run two D8Bs side-by-side, one with the old motherboard and one with the new motherboard - both with the same amount of RAM. I found ZERO discernible performance differences between them.

Even the boot-up time was within less than 5 seconds of each other (..and I don't recall if it was even the old board that was slower to boot or the newer... a minor difference such as how long it takes to count through the memory would make a bigger difference than the motherboard's theoretical performance). I know some others claim that there's HUGE difference, but I can only imagine that they said so "by feel" rather than booting the two types of D8B boards up simultaneously.

I don't know for sure, but so far, was under the impression that the rack unit mainly does 2 things:
- Provide power to the console
- Render the user interface on the monitor and handle keyboard/mouse input, etc.

...but I don't think it does any audio-processing. I think that's all done on the DSPs in the console (but correct me if I'm wrong).

So, to show the GUI, it doesn't really matter if you have the old board with a Celeron 166 MHz or a Celeron with over 400 Mhz (fastest I've seen so far for a D8B). The display and response will be the same.

As for myself, I intend to put my MAIN D8B unit (old board/louder b/c fewer mods) into a new machine closet, and keep a "backup" unit (new board/quieter) close to the console (b/c I only have one long BFC cable).
I still decided to use the "old board" unit as my MAIN D8B rack unit, even though I'm doing a major re-arrangement of my studio gear... should say something about my confidence in there NOT being a performance difference between the old and new motherboards

[Bruce Graham]

Hi Guys;
Thanks for this.
The main reason for the swap on my second d8b has to do the the Hard Drive. I could not get a Compact Flash or SSD to work with the old motherboard. No matter what I try. If there is a way that would be great then I have a spare newer Motherboard instead of spare Older mother board. Thanks to arjepsen!
It has not been a perfornace issue of the older mother board.
As always this forum has great help.
Cheers
Bruce
PS Y-my-R, I haven't forgotten!

[Y-my-R]

Now that you mention using a CF with the old board... last time that came up, I "think" I was still running a spinning drive in that unit (not sure anymore), but I do use a CF card with BOTH units I'm setting up right now (one of them uses the old board)... and that part works in both.

IMO, the trickiest part about getting the Mackie OS to work on a new drive (spinning or CF - same thing from my experience), is to get the drive formatted correctly, with the boot sector being written just the way the Mackie OS likes it. It's good to format from Windows or macOS first, to make sure that the D8B computer hardware can see the drive/cf, but it is still necessary to format the drive "the D8B way".

I think many think that's not necessary, since you can just copy stuff onto the existing Mackie OS drive without formatting it again... The only reason that would still work, is because the boot sector is still the same as when the Mackie OS installer formatted the drive... if you were to format the spinning drive with a Mac or PC, and then re-install from the Mackie OS floppies without doing the "format:on" thing from the first floppy first, it would also fail to boot after installation.

Also, when using an app to "clone" the spinning drive to a new drive (or CF card) with an app that is suitable for that (Macrium Reflect, Norton Ghost, Clonezilla, etc.... but NOT Carbon Copy Cloner, SuperDuper or most of the many "Backup" apps that are commercially available... those often don't clone the boot sector), then the "Mackie Boot Sector" also gets copied/written to the new drive, which will make this work as well.

What's NOT going to work, is to format the CF card on a Mac or Windows computer, and then copy the files from an existing spinning Mackie OS drive to it. This will result in a boot failure/error. My suspicion is, that in a roundabout way, that's probably where you ended up with your CF card (Mackie OS installed, but boot sector wrong so booting is not possible).

So, long story short... if you do the "format:on" thing on the first installation floppy, make sure the formatting process is successful and then install the Mackie OS to the CF (as I described in the "d8b died" thread from a few days ago), then a CF card should work with "old board" D8Bs as well.

That is... there could of course still be BIOS version differences that make it work with one unit but not the other. So, if the format:on thing, and formatting/installing from the floppies to the CF doesn't work, let me know. Let's compare our BIOS versions in that case (...can't check right now).

And Bruce... thanks so much for still planning to do that, I really appreciate that! And there's still no rush. I think I fried my main console the other day, after all (I had some wires reversed in the power supply), and it will take me a while to get that all sorted and the console swapped out... I'll swap a few fader boards around while I'm at it, etc.). So... no rush at all - I'm not even up and running at this point. But THANK YOU!!!

[Bruce Graham]

Hey Y-my-R;
As always thanks fot the very detailed response.
I wil try again making sure I follow your processes. I am sure, as you stated, I missed a process in doing this!
Back to ebay to by some more STUFF!

Cheers
Bruce