MDR 24/96 Motherboard Replacement

[juanbanzai]

Hello.

I've got an MDR that will not access or read the floppy or the HD. I had the exact problem with the drives in the power supply for my d8b and after swapping out multiple IDE cables and hard drives, I found out that the IDE controller on the motherboard was the culprit. Once I swapped the board, the drives started functioning perfectly.

With the MDR showing the exact same symptoms after similar testing, I'd like to swap out it's MB... but this is 2022 and the board in the MDR was from 2001. Does anyone know any possible replacements that could be used or can I safely use any older MB that has PCI, PCI-Express, and ISA slots on it?

Finally, with the MDR being completely self contained, how would you go about swapping out a drive or checking the BIOS of the MB if you can't plug a keyboard or mouse into the unit?

Thanks for the help.

Aaron

[Y-my-R]

I read your post about the D8B board you swapped and I'm glad that this worked out for you... I've been following this forum at least weekly for the past 4 or 5 years, though and in that time, there was nobody else with a bad IDE controller on the motherboard of a D8B or of an HDR/MDR.

Seems kind of unlikely, that every unit you try to resurrect, should have a bad IDE controller on the mainboard.

Because of that, I suspect that the board isn't actually bad and that there's something else that isn't right... like the LBA vs regular setting for the drive in the BIOS, that you had initially missed for the D8B last time.
Before swapping anything, I'd be REALLY careful to triple-check all the BIOS settings and try with a few different drives, etc. before giving up on that board.

I'm also saying that, because those boards are somewhat rare, and you can NOT simply use a board with a similar configuration. I'm not 100% sure how many different board models were used in the HDR/MDR... but for the D8B, it was only 2. And I'm not aware of a different board than those 2 working (and have experimented with getting a few similar "vintage" boards to work, but to no avail).

I "think" someone shared a link recently, where you can still buy HDR/MDR replacement boards from Mackie in Europe, directly. If I recall right, they went for around 150-170 Euro or so. I can try to dig it up if you can't find it... but would still try to resurrect the current mainboard, first.

As for troubleshooting an MDR - I'd just stick ANY video card in there, that fits. Like the one from your D8B. It won't show a GUI for the OS, but it will show the BIOS.

There's also a modified BIOS chip available, that can turn your MDR into an HDR. Then you'd need a compatible video card, though (I think Radeon 7000 were the ones for the HDR... but maybe even the D8B video card will work... sounds like you had access to some parts from work, right?)

The MDR also has a keyboard connector under the sticker on the back, btw. You'll just have to cut a hole in it, then you can connect a keyboard with a DIN-5 connector and use it to change settings in the BIOS with it (along with "any" video card installed, in order to see the BIOS).

Best of luck!

[doktor1360]

I "think" someone shared a link recently, where you can still buy HDR/MDR replacement boards from Mackie in Europe, directly. If I recall right, they went for around 150-170 Euro or so. I can try to dig it up if you can't find it... but would still try to resurrect the current mainboard, first.

Aaron... this is the link Y-my-R was alluding to, ~ $182USD:

https://loudtechnologies.eu/shop/en/other-parts/gcb50-bx-oem-pcb-motherboard/a-2107-29

Only four left in stock - there were 10 of them about 3 months ago... ouch!

[juanbanzai]

Thanks for the replies, gents.

You know, Y-my-R... you may be 100% correct. There's a break in my timeline for bringing the d8b around to working condition. We actually had two 24/96 recorders in our studio at one time; an MDR and an HDR. I was tasked with trying to salvage one of them to try and get dozens of the removable hard drives archived. The HDR would boot, but the hard drive was hit or miss. It screeched like banshee and would only boot the unit once out of five tries. Eventually, it just stopped booting completely. The MDR wouldn't boot at all. When I pulled the hard drive out and tested it on an external IDE to USB adapter, the drive could not be read.

Both of these units were checked PRIOR to my trying to get the d8b working because I could at least try using the MDR as a stand-alone unit since it had the 24-pin analog audio connectors on the back and I still had the snake to connect the unit directly to another analog board. But like I said, after power-on, the unit would just sit for 3 minutes or so before it came back with a message saying the host could not load. I didn't know at the time how to connect a monitor or keyboard to the unit since I thought it was a stand-alone drive.

So fast-forward a couple of weeks and now I'm digging into the power supply of the d8b and it's showing the same hard drive failure the MDR and the HDR were showing. The ONLY way I was able to get the d8b to work was by replacing the motherboard. But now that I know how to plug a keyboard into the MDR, I can also connect a monitor and see what the BIOS says.

Incidentally, there's a brand new 20g Maxtor drive in the MDR. I loaded an MDR image on the drive in the hopes it would work. Before I installed the Maxtor, I tried two different Western Digital drives... both readable by my IDE to USB adapter. Neither of those were read by the MDR.

I don't know if this provides any possible cause for these units having issues (like a motherboard failure), but they were purchased new in 2000 and kept in continuous service until 2016. They were pretty much NEVER shut down since they were used in the production studio of one of our radio stations.

Thanks again for the help.

Aaron

[Y-my-R]

You may already be aware of all of this, but I can't tell if you do, and some of these points may be related to what's going wrong, if you don't... so, here are some bits of info about the HDR/MDR and D8B:

- The MDR and HDR use the same motherboard
- There is a "large harddrive" BIOS available for the HDR, that allows you to use larger drives than originally possible (forgot what the new limit is)
- The MDR can be converted into an HDR via an updated BIOS (I think... or was there a different chip that needs to be replaced?) and an added compatible video card (Radeon 7000, I think).
- The "newer" type of D8B mainboard, is the same board as in the HDR/MDR (but I don't know how the BIOS versions compare).

ALL of the above boards (and old motherboards in general) will forget all of their BIOS settings, if that button-battery runs empty.
If you're trying to make the BIOS settings on an old battery, then re-start to try if the setting changes worked out, they're likely lost before they're loaded on restart. So, if you never replaced the battery, that's why the drives may not be found, too.
So, put in a new battery first, THEN make sure the BIOS settings are correct per the info in the database.

Like the D8B, the HDR/MDR can also be run off of a CF card for the operating system. This also makes them much quieter. The idea is, that you'd record via the external drive bay (which can also be converted to use an SSD drive inside the bay, or even a different, newer style bay), but run the OS from an internal CF card (or in my case, I have it stick out the back from a slot cover... makes it easier to get to, if I ever need to change something).

If you intend to keep using the HDR/MDR, it would make sense to go straight to a CF conversion (but IMO, it would still make sense to go there to transfer the external drives, since you won't have to mess with a temperamental old IDE spinning drive).
There's some posts on here, that list what parts to get and how to do it (but if you go that route, mention it here... there was one part that did NOT Work out in the BOM (bill of materials) that was shared on here, that needs to be substituted to make SSD drives work for the recording drive.

Also, if you have an MDR and HDR... even if the HDR board may be bad, don't throw it away. You can use the BIOS chip and video card to convert your MDR into an HDR, if the MDR is otherwise in better shape.

...and also just so you're aware... replacing the mainboard or WORSE, replacing the drive-bay in the HDR/MDR is a lot of work and really annoying. To get to the drive-bay, you have to take the whole motherboard out, to get to the metal bracket below it.
So, already because of that, I'd try everything I can before deciding to replace the board in an HDR/MDR

As for all your old drives failing or not being recognized... what's the BIOS settings for the IDE controllers? Are they both turned on and set to Auto-Detect drives?
Were these drives originally for the HDR/MDR? If not, you may need to check the jumpers on the harddrive(s) to make sure their set for Master or Slave operation... or when in doubt, you can try if it works with the jumper in the "Cable Select" position.
...or to ask differently... do you have experience messing with these old Pentium based systems? There's a few things that were a bit trickier than on newer computers with SATA, etc (e.g. like the mentioned Master/Slave jumpering... but also the LBA mode you mentioned the other day, etc.).

And just on a side-note... of course old IDE drives can't really be trusted with sensitive data anymore... but the failure rate your describing surprises me. I think I still have at least 10 or so old IDE drives that I use for various little experiments and projects. They don't get much use and have been resting for much of the past 20 years... but none of mine went bad just from sitting around. Do you live in a corrosive climate or something?

[juanbanzai]

Thanks Y-my-R for the reply.

I actually have a bit of good news to report. I put the MDR aside and took the HDR completely apart... and yes, it wasn't easy. I removed every board, cable, drive, memory, etc. All the connections were cleaned on the motherboard and likewise the connectors to the drives, and header pins. Installed a brand new lithium battery and carefully reassembled. I booted the HDR and low and behold, the BIOS detected the new 20g drive I swapped from the MDR. Wow! For the first time with this unit, progress finally.

I checked the BIOS and everything seemed to be where it should be, but I can only base what I'm seeing off the BIOS settings for the d8b. I didn't see a BIOS setting chart for the HDR unless I completely missed it. Anyway, I downloaded the image file for HDR OS 1.3 build 402 because the notes I found on the box for the unit said that was the latest version installed... not that it matters.

Got two floppies ready and edited the tools.ini file to format the new drive in the HDR. The bad news is that after the floppy booted the system, it hung. I didn't get any notification to insert disk two, nor was there any progress to be seen on the display of the HDR. Sometimes I'd get a green asterisk flashing in the upper right corner, other times, I'd get nothing; the screen would just go black with not indication that something was happening. And yes... I made sure that "format:on" was typed correctly.

I checked the BIOS settings once again and noticed that the hard drive was set for LBR. Just for kicks, I changed it to NORMAL and tried installed the OS again but got the same results.

Wondering if I'd have better luck just popping an image of the OS directly to the hard drive, but I honestly don't want to waste the time if I'm going to have the same results I had with trying to do the same on the d8b; the unit wouldn't boot from the drive with the image installed.

Thanks again,

Aaron

[juanbanzai]

Just a quick note... I found the BIOS settings for the HDR. There were only two that were different from what I had set compared to those in the manual.

I did check the master/slave jumper on the back of the drive in both the "single" and "master" setting. If I have the jumper for the drive set to "master", the BIOS doesn't detect the drive... which is strange since I thought the removeable drives would make the unit think there was a "master/slave" environment. The BIOS only detects the drive in the "single" setting, but the OS install floppies don't see the drive at all.

Anyway, I decided to put the OS install using floppies idea aside and then went for installing an image of the HDR OS. THAT actually provided me with better results. The HDR booted to the Mackie HDR "welcome" screen, and the word clock card lit up. I also noticed that the three optical cards had some life at the i/o ports. However, after several seconds, the "error 43" showed up on the HDR's screen and the system locked. The video out was still showing the welcome screen, but eventually it went to a "tracks" screen with an error window that said "Boot error: surface not responding."

IMG_0612.jpg (Array KiB) Viewed 4394 times

[doktor1360]

Just a quick note... I found the BIOS settings for the HDR. There were only two that were different from what I had set compared to those in the manual.

I did check the master/slave jumper on the back of the drive in both the "single" and "master" setting. If I have the jumper for the drive set to "master", the BIOS doesn't detect the drive... which is strange since I thought the removeable drives would make the unit think there was a "master/slave" environment. The BIOS only detects the drive in the "single" setting, but the OS install floppies don't see the drive at all.

Anyway, I decided to put the OS install using floppies idea aside and then went for installing an image of the HDR OS. THAT actually provided me with better results. The HDR booted to the Mackie HDR "welcome" screen, and the word clock card lit up. I also noticed that the three optical cards had some life at the i/o ports. However, after several seconds, the "error 43" showed up on the HDR's screen and the system locked. The video out was still showing the welcome screen, but eventually it went to a "tracks" screen with an error window that said "Boot error: surface not responding."

IMG_0612.jpg

Spidey Sense tingles looking at that... based on the steps leading up to what you've done prior to this I'd have to say that's a hardware related error msg, particularly disk controller related. That's not to say it's the end all issue, but it does indicate reading the disk as the current malady. This gear (D8B, HDR, etal) is old & mercurial as hell, very temperamental... 95% temper, 5% mental (*grins*).

Personally, I"d review the hardware breakdown and reconstruction. I rebuilt two of these, and helped Y-my-R remotely bring his recorder into the 21st century (all things being considered) as well. So, I'm not shooting from the hip here when I say that it may be something related to putting it back together. I've done this myself... I lost serial communication on one endeavor, only to discover that one of the small ribbon cables connecting the comm card to the mobo wasn't correctly seated. It wasn't something I noticed on a quick scan, I discovered it when I got seriously pissed off and started to do a more thorough revue of everything I did to mitigate the issue. Point being, the issue might be something as simple as that... or a bent pin, etc... I'd go as far as actually blowing out the connectors with air (dust?), just cleaning up things as best as I could...

I'm sure you can work thru this, and it'll probably be even more frustrating than it is for you right now... so just stay with it. Check the IDE chain hardware (again), recheck the BIOS firmware settings... step by step. That's the best advice I can personally give with not having actual physical access to the hardware...

I'll be keeping an eye on this thread,.. as I mentioned, Y-my-R and I have both been down this road before, recently too, so it's not the 1st rodeo with this for either of us by any means... and he's already been stepping up here, too...

As always, the caveat :
[Standard Mgmt Disclaimer] - "Your actual mileage may vary..."

[juanbanzai]

Thanks for the reply, Dok.

I took your advice and went through every cable and piece of hardware again. There were no bent pins on anything, and I made sure that each piece of hardware was connected where it's supposed to go per Mackie. You're right... it's very frustrating because I haven't been able to put my finger on the issue.

Normally when a booting problem like this occurs, it's usually because the software is looking for something it can't find in the system. So when the HDR boots, the BIOS posts and I'm shown a screen that says "this and that" are loading. Right after that, the "Mackie HDR" welcome screen loads and you can hear the hard drive chattering away as if it's searching for something. This leads me to believe that it's looking for a driver, some other piece of software, or a piece of hardware that the boot-up program is told to look for but it's not in my system.

So with that said, is it possible that the image file I installed (which I obtained from this forum) is from a system that had some and additional or different "something" installed that is NOT in my HDR? Without the ability to find that "something" the system just crashes.

Is that plausible, and if so, is there a way to check the OS that's installed on my HDR to see if anything is amiss?

And the HDR is now the least of my worries. I just powered on the d8b and all I got was loud popping coming from the speakers and several of the meters on the board are just flashing. There's also a loud click coming from somewhere inside the board. Is this the dreaded "rail cap fail?" I'll address this on another thread if I can't find what's going on. To me, it sounds like some caps in the power supply blew.

Thanks again.

Aaron

Aaron

[Y-my-R]

I've worked much less on HDR/MDRs than on D8Bs, so I'm not sure what the error messages mean... but I had previously thought, that the "Surface not Responding" is pretty much the same thing as when the D8B rack unit can't find the control surface (the console).

Just, in the HDR's case, I thought it's the front panel with the arm buttons and meters, etc., that isn't responding, that would cause that error.

...but maybe I'm wrong. Sounded like the Dok was pretty sure about the cause of this.

I had an error "sort of like that" (but not sure if it was that exact one), after I had an HDR apart, but then forgot to connect a little two pin cable to the front panel of the HDR. I think that cable powers the whole thing... And when the HDR thinks its front panel controls aren't working, I think it throws an error "like that" and refuses to work at all (e.g. via the mouse on a monitor).

Again, I could be wrong, but I'd recommend to pop the lid and double-check that the cable to the front panel is connected (if I recall right, that was close to an upper corner of the front panel, but the cable can drop down and not look like it's missing - that's what had happened to me... but I think the LCD display on the front of the unit also didn't light up as a result, so I knew something was wrong).

Anyway... if everything lights up on the front, then it's probably unrelated to what I'm saying. Just thought I'd mention, just in case.

And sorry about the possible rail cap failure... so far I was lucky and never had that with any of my 3 D8Bs. Best of luck!