A hardware fault

[davet]

I have a D8B in for repair that I am currently working on. I am wondering if anyone else has had this fault or am I the first to find it? This D8B has all the LED's on on channels 2 - 12 channels, channel 1 seems to be normal. None of the control surface switches actually changes the LED states but they do seem to work properly and can of course be seen on the monitor. The audio seems unaffected. So it is a one way communication issue with the control surface PCB that would suggest a multiplexing issue between the brain board, the surface PCB or one of its components. The Another issue that may indicate where the fault lays is on the brain board where the middle of the three LED's (D3 yellow) attached to an output of U25 never operates. So if you have had your D8B open when it is on and have seen all three LED's on (I think they flash with data transfer though quite what data as yet I don't know) then that would tell me much about the fault here!

The PC side is relatively interesting and I can't see any Windows / Microsoft based PC lasting as long as these Linux boxes have. The fact that they are moderately different internally on the power supply side as you would expect should not be anything other than an exciting challenge! I have been a PC / computer engineer for over 25 years and an electronics engineer for more than 40 so I have been around a while. The one thing with this unit I would rather not cause more issues if I can possibly help it, so if anyone has seen this fault before and found a cure before I get that nasty control surface PCB out of the box then I would greatly appreciate it!

By the way, has anyone else been able to get any help with these directly from the Manufacturer or its USA dealer / service agents? My conversations with Mackie were okay but in the end not very helpful and only directed me to the said service companies who so far have not responded.

Regards

Dave

[Bruce Graham]

Hi Dave & welcome;

For starters, I have not experienced what you have going on there, but.... what has worked as a general statement of "This Works Most Of The Time" is to clean all the contacts on the Ribbon Connectors inside the d8b surface as well as the CPU/PSU. It seems to correct a lot of wiedness. Use a good contact cleaner and be very careful with the edge connectors. They are somewhat delicate.

You should also check your BIOs, although this doesn't sound like it is that problem.

If you are building from the "Startup File", try deleting it. Upon booting the d8b will create a new file. Note: if there are things you like to have in your start up file you will need to make the changes and re save it as the same name (I.E. Faders To Tape or Filtering Off, or Solo latching, etc).

Also check the Maintenance section at the top of this forum Home Page (called "Database"). Lots of advice and experience there.

I have been able to do most of the repairs on my d8b's and I'm not a Service Tech. When it comes to difficult soldering (replacing Caps and IC's), I send it to my local shop who have been helpful. But it sounds like you know your way around the inside of PC Boards. Mackie isn't really Mackie any more and the ones who created this beast we all love have either left or have been told to "Shut The Front Door" (if you know what I mean, by the new owners Loud Technologies.

Others will chirp in here. It has been kind of quiet on this forum the past few months but the d8b Forum Gods do check in from time-to-time and will help as they can! A good crew here.

Again welcome.
Bruce

[davet]

Hi there. Many thanks for the reply. I will admit I have done all the usual things, ribbon cables, duff stuff on the PC (which I didn't really expect as its not that sort of fault) but while I had it open I changed fans that were noisy, replaced a couple of caps on the motherboard that were blown, cleaned the dimm, cleaned out all the power supply fluff and checked through all the software all which suggested it was healthy. These are effectively locked down systems for most peoples purposes as your not going to go browsing the web with them so I have a feeling that most of these machines are as they were released! There is nothing special about the PC although you would be advised to try to match motherboard chipsets if you had to replace one. The complicated bit is the power supply which needs some thought as to a good way to deal with it if it fails. The standard PC psu can be modified to fit if it has to be replaced but finding an old school psu with the right connectors for the motherboard could be interesting. And of course they do not have the standby / remote switching of an ATX psu so that needs some thought! If you don't know what your doing of course you could get into trouble.

I had a word with the owner and he is keen to get it back and running correctly so I have a feeling I will be taking out the 12 channel surface board and making some decisions as to what to replace. In the meantime there is another complete but scrap unit on its way to me that can be cannibalised for spare boards. The only issue will be the software licences. I think that the front panel board will be licence free as it has nothing on it in the way of firmware so there should be no conflict on this front. The brain board however will cause conflicts which will need some consideration if I have to swap it. I am still interested in anyone who might have opened theirs and seen the three LED's on the brain board flashing away. They should be red, yellow and green but my yellow middle one doesn't do anything so I would love to know if its supposed to.

If anyone else has seen this I would be only to happy to hear from you.

In the meantime I am planning to get back to renovating a Soundcraft 2A 24/8 mixer from 1978 tonight.

Regards and thanks

Dave

dave_london@hotmail.com

[Crash]

http://www.sonido-7.com/d8b/files/d8bservice/D8bsm.pdf

Page 11 should be of interest to you.

[davet]

Many thanks

There is nothing better when your chasing a fault than plenty of information!!

When I find what fixes it in the next couple of days I hope I will let everyone know!

Regards

Dave

[anyhorizon]

Does the problem occur when bank 24 - 48 is selected?

Peter

[anyhorizon]

Also, what happens if you solo one of the muted channels?

Peter