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Solution: Faulty PSU connection to DSP/Backplane

Discussion board for Mackie's d8b Digital Console users.

Solution: Faulty PSU connection to DSP/Backplane

Postby topdiggy2 » Mon Dec 01, 2014 7:31 am

Hi Guys -

Here is my contribution to the D8B community...yet again.

So i own 2 D8bs that i use in a dual setup, you can search my post for details of my rig...anyway, one of my boards keeps cutting out periodically during the day. Meaning, i would just loose audio in the middle of a session, in fact, i would loose all signal coming from the cards in the cage, meters, as well as analog inputs. But yet i would still have the rest of the board working as normal....fader banks, buttons, pots, menus, lcd screen, etc....all would work fine.

Here in the D8b database, I found the issue and sure enough, that bad psu cable/connection was the culprit. However, the only fix was for me to shut down, take the bottom off and go inside reseat the cable. Then close it back up, power on again and it would be working fine again....for 15 minutes, then it would do it again. Some days would be better than others where i would get 4-8hrs at a time, but, if i shut off the board to leave or something, i would have reseat the cable again BEFORE i could get sound again.

If this is happening to you, then you probably understand the frustration. I just said, to hell with it and decided to just do away with that finicky molex connect (the white crimp/molex connectors on original wire) and decided to hardwire (solder) my own cable to these pins for a permanent fix.

Here is what i did

Materials: **** 45mins****
(4) approx 30" 16awg hookup wire - use different colors if you can
(4) crimp style pins ****
solder gun/needle
solder
needle nose pliers
GOOD LIGHTING

***Note: (similiar to mine shown in photos, but, not as thick..radio shack was out of the thinner models so i just bought what they had...but you want the thinnest easier to crimp style you can find.


Step #1 - build wire harnest

I remove the original cable to get and idea of length and i cut 4 pcs of hook up wire slightly longer as shown here in the picture below:

20141130_182059.jpg
Step #1 - new Wires & original wire connectors
20141130_182059.jpg (Array KiB) Viewed 904 times


Strip both ends of each wire enough to fit into your crimp connector.

20141130_182837.jpg
Strip each wire about 1/8", not too long, you want it to fit inside the crimp.
20141130_182837.jpg (Array MiB) Viewed 904 times


Now, at this time i place a small amount of solder inside the crimp that server 2 purposes: 1) secures the hookup wire inside the crimp, and 2) once in place on the lead pin, when we apply heat to the crimp, the solder will bond with the pin to secure the crimp in place.

20141130_183411.jpg
Solder the hookup wire inside the crimp. The crimp down on it to secure it further.
20141130_183411.jpg (Array MiB) Viewed 904 times


This is what is should look like when you finish this step

20141130_184124.jpg
finished hookup wire on crimp.
20141130_184124.jpg (Array MiB) Viewed 904 times


Step 2 - Disconnect all wiring to the console, place upside down onto of a pillow or 2 towels rolled up.
I will not be removing any of the pcbs. I can manage to access the area i need simply by disconnecting a few ribbon cables that get in the way. If you can NOT do this, then i suggest removing the pcbs and working on them on a flat surface!!!! WARNING you will need a steady hand and a fine point solder tip shown below to get into these somewhat tight spaces.

20141130_192010.jpg
needle tip solder .
20141130_192010.jpg (Array MiB) Viewed 904 times


Now, we simply place the new wires on the correct pins, crimp down with our pliers, and apply heat (and more solder if necessary).

NOTE: Please note from the pictures that i work on the PCB inside the unit, i did not remove the pcb at all. If you find it difficult to see or reach the pins with your solder gun, then i suggest removing the pcb and work on them on your bench...thats actually the more proper way of doing it!


Also note, because I am working with the pcb boards still attached, i start working with the pins furthest away from me until the last pin to work on was the closet to me. That way i always had the room i need to move around in there.

Here is what it looks like finished
topdiggy2
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Joined: Sat Apr 26, 2014 4:23 am
Location: Atlanta, GA

Re: Solution: Faulty PSU connection to DSP/Backplane

Postby topdiggy2 » Mon Dec 01, 2014 7:34 am

Finished product....sorry, only could upload 5 pics at a time.

Here is the partially finished DSP side

NOTE: Yes, as you can see i got too close to that connector with my solder tip and burned it a little. Again, if you can't get into these tight spaces with a steady hand, then please remove the PCB and work on a flat surface (table, bench, whatever...)

20141130_191951.jpg
finished DSP side
20141130_191951.jpg (Array MiB) Viewed 903 times


Here is the PSU side

20141130_203839.jpg
finished PSU side
20141130_203839.jpg (Array MiB) Viewed 903 times
topdiggy2
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Posts: 118
Joined: Sat Apr 26, 2014 4:23 am
Location: Atlanta, GA

Re: Solution: Faulty PSU connection to DSP/Backplane

Postby garrett21allen » Thu Dec 04, 2014 5:18 am

Hi Topdiggy2

thanks for posting the pictures. however two pictures I do not understand
because on my end in two pictures its just showing fuzzy and I can't see anything on
the two pictures. but maybe its my computer because I have been having trouble
with it for the last two weeks. it will not let me post a new topic in the d8b forum but it will
let me do a quick reply on any post. but the new topic button is not even showing on my computer
it use to be on the upper left side now I don't see the new topic button anywhere. and I don't know
what wrong but like I said it could be my computer the reason I can't see the pictures. I also wish I
could get the new topic button fixed but I don't know what to do. I ask peter about it he said he
did not understand it ether. thanks again.

Joe Allen
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Re: Solution: Faulty PSU connection to DSP/Backplane

Postby topdiggy2 » Thu Dec 04, 2014 5:57 am

@ joe

No problem if you want me to email them to you send me a email addy...no problem. Or I can upload them to my dropbox and post a link.
topdiggy2
Premium Member
Premium Member
 
Posts: 118
Joined: Sat Apr 26, 2014 4:23 am
Location: Atlanta, GA


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