The next step was my favorite, and probably easiest; the
Disassembly. I brought the board up to my kitchen table, the only place I had enough room, and even that's not enough! I started by removing each fader and knob one by one and placing them in a container. I thought that would be fast, but you soon realize there are more knobs and faders than you think! Finally I got everything off.
Then it was time to take the plastic trim panels off the sides and the small machine screws holding the circuit boards to the faceplate. I started left to right taking all the #1 screws out, and was having no problems. THEN I got to the screws by the master section. NONE of them would come out. All the screws started stripping. I finally did get one out, and I saw it wasn't a machine screw, but a self-tapping screw; like you'd use in wood. Like this:
So right there a red-flag went off. Why were every one of the screws a machine screw that threaded in nice and easy, then have a random self-tapping screw? Something was wrong.
So then I stood the unit on end to remove the screws holding the top of the board to the chassis. I put the mixer back on the table and the unit slid out of the chassis. So now I can see the back of the circuit boards, and I noticed this:
There were a total of 5 connectors unplugged! So basically channels 1-16 weren't getting any power. My first thought was, "That's it!! I am gonna plug these back in and it will work!". No. I did get some normal functionality back when I turned it on, but still nothing on the output or in the headphones. I can now get signal IN on channels 1-16, so that is a start. I also tried putting an AUX source in through the tape input, and I can hear it through the headphone jack, but it is
extremely distorted. So at this point it is time to do two things. 1) get the screws out holding in the master section, and 2) start troubleshooting.
Next up, part 2 - troubleshooting.
Hi Brian!
ReplyDeleteI recently bought one of these mixers for £100 to use at gigs with my band. I have not had time to look at it yet but it has a similar problem to what you described, only mine isn't across all mic channels, only 10, 12, 13 and 16 where I can get the PFL display and the red and green peak and signal lights to work as they should with the gain setting etc, yet I cannot get an output from anything (mains, aux, etc.). If I turn the outputs and the amps up to max, I can make out a very quiet and distorted version of the source and obviously this isn't useable.
As another little pain, some of the buttons don't always work and sound like they have a dodgy connection. Some, like the fader ones, only output the left channel or only output anything when the button is held down.
My question to you is: did you ever write a troubleshooting part and fix the mixer? and Do you have any idea what is wrong with it before I take a look under the case?
I know it has been many years since you wrote this and I don't know how often you look at the comments but I would appreciate any feedback you have (I'm not expecting a full story though, unless you're prepared to give one) :)
Thanks in advance,
Michael.