D8B died

[RJH_MUSIC]

Thanks - I thought the same, but what puzzles me is why the behavior is following 3 different consoles with same CPU. I checked the voltages at the Linear Supply Board, but I did not check the voltages at the end of the cable. I will have to try that tonight. Also, the BFC cable is really rusty and crusty so I wonder if that had added to the troubles. I took the back bottom off the original console that went south and noted that the led lights on the DSP board did not illuminate properly.

[Y-my-R]

I don't really have a pinpointed idea, but since you said the problem happens with the same CPU/Rack-Unit but with 3 consoles:

How many rack/CPU units do you have available to TEST with? I understand that you want to use the unit with the custom-built power supply and longer BFC cable...

...but if you have an "original" rack unit available for testing purposes, you could try if any of the desks boots up as it should with that rack unit. This way, you should at least be able to figure out which console works as it should and which doesn't.

...once you know THAT, that's where I'd use a "known good" console, and continue troubleshooting with the custom rack unit (and whenever it makes sense, compare the behavior between the custom rack unit and the stock rack unit, to eliminate that as a potential cause).

When I'm troubleshooting something with my D8B, the first couple of questions I ask myself, are usually geared towards pinpointing the issue as quickly as possible... so, questions such as:
- Rack or Console (e.g. try different rack/console combinations)
- Software or Hardware (e.g. try a different CF card with the OS that I have ready, anyway)
...and from there, the questions become more specific (e.g. observed behavior and if it gives clues about where in the hardware the issue is likely to be introduced from, etc.).

In that sense... do you have a "stock" rack unit available, so you could try if your 3 consoles also give you trouble with that?

[doktor1360]

Thanks - I thought the same, but what puzzles me is why the behavior is following 3 different consoles with same CPU. I checked the voltages at the Linear Supply Board, but I did not check the voltages at the end of the cable. I will have to try that tonight. Also, the BFC cable is really rusty and crusty so I wonder if that had added to the troubles. I took the back bottom off the original console that went south and noted that the led lights on the DSP board did not illuminate properly.

That might appear more and more as if something in the power supply in the host involved is the 'x' factor. Could the power supply be wonky under load? Any of the individual voltage supplies could be suspect here, they all manage to work themselves into mix at the ZIF socket on the back of the card cage, tying everything together as it were (i.e. ultimately causing the problem). They're all common points on the card cage where the voltage(s) 'rubber meets the road' because the slot supports different interfaces. However, considering it's also sorta isolated to this particular sub-section hardware, it would then stand to reason to also consider something 'different' in the circuitry where the voltage(s) are concerned... weird. That kinda doesn't make any sense to me in a way, a paradox if you will...

The cpu host does appear to be physical location of the issue (I know, duh LOL)... personally, I find it extremely doubtful that anything is problematic on the pc computer side of that piece of hardware...

However, as always :
[Standard Mgmt Disclaimer] - "Your actual mileage may vary..."

Kinda funky, I'll be paying attention to this one...

[RJH_MUSIC]

Okay - Here is an update. Getting weirder but I think the concerns are correct about power supply, and I think I have multiple issues. First, I agree that with fact that if there different consoles are wonky then the problem must be in the CPU. Unfortunately I do not have another CPU to test it with, so I replaced the Linear Power Supply board and made some success. With no I/O cards installed and no Effects cards installed, I get meter bump which indicates audio is good but the green LED on DSP card does not light, which I would say is correct because no Effects cards installed. After about 2 hours of installing cards one at a time and rebooting each time, I was successful all the way to the point where all I/O slots are filled and only 2 MFX Cards and and one UFX Card are installed for successful boot. My only problem is that the green LED on brain board remains blinking but still indicates I have audio because meters jump. Although I have not confirmed audio because nothing connected yet, (Tonight).

SO here is the weirdness - If I install both UFX cards, then unit fails to establish Red and Green Light solid on DSP board, only Red Solid. That has to be a voltage problem. I think having all 4 effects cards installed might be drawing too much current than is available. So tonight I will swap out the Power distribution board in the console to see if that is the problem. I suspect the CAP that is the circuit that runs to the card cage might be bad. I am unable to inspect the ribbon cable going to the back of the card cage from the brain board because to get at it would be major surgery on the d8b due to its location.

So the problem across all three consoles I think was caused by bad Linear Power Supply in the CPU. What I am left with is figuring out why having all effects card slots filled causes a failure. The blinking green light on the Brain board I think is the result of not having a 5 VDC power supply with sense, which means that pins 3 and 4 on the BFC are dead. Also need to rectify that!

[RJH_MUSIC]

I forgot to mention that this Console has all 48 channels loaded. I have all my outboard synths connected. 1-24 and 24 more using three I/O Cards, so it stands to reason that if there is a CAP failure somewhere, then the 5 VDC power supply cannot handle the load. It is different and has less amperage than the one I used in the other d8b rebuild, which is still operating fine.

[RJH_MUSIC]

I was just looking over the schematics for the power Distribution board in the console, J1 and noticed that Pin 4 is +5 Sense which should be dead in my case since my 5 VDC doesn't have sense, as well as Pin 7 -5 Sense, but as recall my ohm out last night, I noted that pins 3 and 4 were both dead. Pin 3 should not have been dead, and should be carrying -5 VDC. Now I need to trace in the schematics where that goes. That problem is in the original rusty crusty BFC cable. So part of my problem here is tracing down problems with bad components.

[RJH_MUSIC]

Well after several days of troubleshooting my d8b is finally back up and running. Apparently there was nothing wrong with the pins in the BFC, I just was not ohming them out correctly. I also didn't read the service manual correctly as I thought that unless the red and green LEDs on both the brainboard and the DSP board were lit solid than there was something wrong. As it turns out as long as the red lights on both are solid the unit is functioning properly. It could be that the flashing green on my brainboard is the result of having a hacked OS. I really don't know. Without more detailed info on the LED states there us no way to determine. In the end the culprit turned out to be the Apogee clock card which failed. All of the MFX and UFX cards are fine as well as the I/O boards.

[Phil.c]

Well Done

[RJH_MUSIC]

The only thing I really hate about the D8B is that every time you turn it on something else happens. I assume that is due to aging of parts

[doktor1360]

The only thing I really hate about the D8B is that every time you turn it on something else happens. I assume that is due to aging of parts

Mercurial... my platform is stable as hell, in fact I don't even get concerned hitting the 'on' button anymore. I get the occasional anomaly, but nothing that a quick reboot doesn't mitigate. BUT, when they do go sideways, it can be a real mf-r working things out to restore order... can be stomach-turning at times. You know, we all just get to the point of putting up with the hiccups...

About the best definition is the stereotypical 'Love/Hate' relationship...

Really good to hear you righted the ship...