Mackie 1604-VLZ needs repair. Anyone got a schematic?

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OlympicPhil

Well-known member
Joined
Sep 13, 2004
Messages
70
Hi, I've got a Mackie 1604-VLZ in my workshop for repair.

The Solos don't mute the other channels, there's no left-hand-side from either the main outs or the ctrl rm outs (or present on the main level indicator lights), solos don't do anything when using the main outs, and when on ctrl rm outs, the LHS works when on PFL but not AFL. (still no muting of other channels when a channel is soloed, but level indicator lights work too in this mode).

It does look as if someone's thrown up inside the box on the 1st 2 channels so I'm going to clean this up and check the components as there could be some heat/liquid damage here under the gunk.

I've got a feeling that there's 2 main problems - the left pan assign controller and the solo controllers. I'm going to start by cleaning them up with some switch cleaner and get a DMM across them to see what's going on, but I don't have a schematic unfortunately so it could be a slow process.

I've got the user manual etc from the Mackie Website, but there's no schematic with it, just a block signal flow diagram.

Does anyone have a wiring diagram for this mixer?

Here's hoping,

Phil
 
if that link doesn't help, i have the mackie analog service CD that has the schematics for that on it. I could email those pdfs to you.

:guinness:
 
Thanks for the link - I've downloaded those schematics.

Does anyone happen to know the difference between the CR1604-VLZ and the VR1604-VLZ?

This schematic's for the VR whereas the one I have on my desk is a CR.

Thanks again for your help,

Phil
 
I work at a repair place that is authorized to repair Mackie stuff and have a fair amount of time being elbows deep these mixers. I have never heard of a VR1604 (it could be an export model number) but have seen plenty of CR1604's (in fact I have one about a foot from my right elbow here in my studio). There are two different CR1604vlz's, one is the vlz "plain" and the other is the vlz "pro"....different mic pre's in them is the biggest difference.
As far as your problem goes, Mackie had some issues with flat cables used in their "vlz" series mixers for a while that would cause a variety of problems.... as I remember, some which sound like those of which you described.
I have called Mackie Support several times and have always been treated very well and not because I was an Authorized SC for them...for all they knew, I could've been Joe Schmoe off the street. If you explain that you are a tech, my experience has been that they will help you as much as they can over the phone, within reason.
Good Luck and let me know if you still need a schematic.
TP
 
Hi TP,

Would you mind if I asked you a quick question?

I have a 1604vlz - after being turned on for a few minutes, all the solo lights trigger and a deafening sawtooth-like oscillation is emitted from the master outs. I noticed a chap at another forum had an identical fault on his, but he couldn't tell me what it was as Mackie fixed it for him.

My suspicion is either the LM317 / 337 are faulty and breaking out of regulation, would that make sense?

Thanks,
Justin
 
ah - must've been a typo on that site... the schematics themselves say CR not VR.

Hmmmn... I've cleaned up the gunk from the mainboard, switched it all on again and now the RIGHT side's distorting too!
 
[quote author="OlympicPhil"]ah - must've been a typo on that site... the schematics themselves say CR not VR[/quote]

Sorry about that - I've corrected it now..

Jakob E.
 
Hi Thermionic....check for fractured solder joints in the power supply module. A fairly common problem as the PS generates a fair amount of heat....with the heating/cooling cycles, the solder expands and contracts and starts to fracture causing heat related problems. Actually a very common problem in about 75% of the stuff that comes across my bench.
All that to say that I have never heard of the problem you are having but most power supply problems are traced back to faulty solder joint connections.
Good Luck...
TP
 
Thanks again for all your help, guys.

I've had my head inside this thing most of the day now, and I think I'm cutting down the possibilities, but then again, I still feel way short of a conclusion.

Here's my symptoms:

1. Channels 1,2,7,8,9,10,13,14,15,16 - no left channel in normal mode and PFL mode, works fine in AFL(SIP) mode.

Channels 3,4,5,6,11,12 - no left channel in normal mode and PFL mode, works fine in AFL(SIP) mode, plus heavy distortion and intermittency in all modes.

2. Channel Solo buttons don't mute the other channels.

3. Rude Solo light not working at all

4. When a channel is SIP'd (but the LR-Mix button is out) and the sound is panned centrally then the LR-Mix button is pressed, the sound becomes more LEFT-heavy. (the opposite to what you'd expect when you take the above faults into consideration).

5. When I clean channel 1's buttons, fader, trim pot and pan pot with switch cleaner, it works fine (both channels) for 30s or so, then dies again. (Sounds like either TOO gunked up for cleaning to work or a cap discharging - maybe due to a piece of gunk across some terminals.

Also possibly of note: tape input works fine both sides.

The more I'm probing about this thing, the more problems I'm finding.
I've not even started with a DMM yet and I'm tearing my hair out already.

Damn, why can't our clients just use our SSLs and be happy?!

Phil
 
OlympicPhil,
Did you get a schemo on that thing yet? Let me know....
I can't imagine trying to troubleshoot that thing without one
Test Point

If you need one, let me know if you have the "plain" vlz or the vlz "pro".
 
[quote author="Test Point"]Hi Thermionic....check for fractured solder joints in the power supply module. A fairly common problem as the PS generates a fair amount of heat....with the heating/cooling cycles, the solder expands and contracts and starts to fracture causing heat related problems. Actually a very common problem in about 75% of the stuff that comes across my bench.
All that to say that I have never heard of the problem you are having but most power supply problems are traced back to faulty solder joint connections.
Good Luck...
TP[/quote]

Thanks :guinness:

Justin
 
Hi Testpoint,

Not yet, I wasn't working yesterday, but I'll probably have time today to get my head back into it.

I'm going to bang a sin wave through it from a sig gen and scope it to see if I can locate the point that those 6 channels get distorted.

Then I'll check the voltage rails and make sure the thing's getting the correct power all over the board for the solo/left channel missing problem.

If no luck after that I'll start testing the caps etc.

Incidentally, if anyone's come across problems like these before I'd certainly appreciate any advice.

Phil
 
heh, suggest it to the studio manager, she might just go for that.
For the price of a VLZ-pro, you could probably have at least 5 hours in Studio 3. :)

Phil
 
Right, I've sorted the missing left-channel problem.

I traced a sin wave all the way from pan pot to output and it turned out that the left channel wasn't missing until the main fader.
I took the main fader apart and it was completely gunked up.

The brushes on the vca were dragging some dirt-fluff up and down the tracks with it.

Bit of isopropanol and a baby bud and all's well with the left channel now.

Now I've just got those 6 distorting channels and the solo problem.

The studio's quiet today so I'm going to have a crack at it a bit later.

Phil
 

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