I'd check the feedback loop on the fader assembly. The faders are easily replaced if I recall. I'd rule out a board failure since those are 8 channel boards and you'd have an identical issue on two separate boards. But never say never.

AAAAAAHHHG Just noticed another one too. While trying a submix on subs 1,2,3 & 4 number 2 decided it would do the same. So now the problem is on board 2, board 3 and on the sub group board. I know these had an inherent problem with the ribbon cables too. Mine are the original ones,not even rev b or c let alone g. I did wonder if it was the fader buffers (and they're surface mount..grrrrr). Is mackie still the best place for spares or does anyone know any other sources ?

I've had good luck getting spare parts from Mackie. Faders are available elsewhere of course you're willing to customize the mounts. If this the original edition you might have a wrasslin match on your hands due to age.

Surface mount isn't so bad if you lay off the coffee for a bit first. Make sure you have some solder wick braid as it will make your life much easier. One of those suction cup magnifying glasses doesn't hurt either. You could order a single fader from Mackie and see if that fixes the first problem. Proceed accordingly from there. If Remy sees this posting she might tell you how to check the feedback loop on a fader. She posted about it four or five months ago but I can't remember where it was.

 

OK folks, I have been looking for a thread on this site to post what appears to be an unknown or undiscovered fact about Mackie 'Bus8' products.

I have been asked by my friend to figure what was going on with his 16.8 Mackie and I will post my results here. If you want my opinions about how this Mackie condition came to be I would be pleased to add comment but here is the base facts I have discovered about 'this' Mackie product.

The original complaint from my friend was; "I searched the forums and the best solution offered for the lost gain, noise, and funky EQ response was to replace the ribbons. I did that but now it has lost a channel and other stuff is wrong".

I have spent two weeks restoring his channel boards and I am certain that he could not be the only customer with product shipped from Mackie having this problem. His mixer is about five years old. I have attached a photo of the problem. The short story is that Mackie shipped product with defective circuit boards. The problem originated at the pcb manufacturer, my guess is it was a vendor for Mackie. The problem was not discovered by the quality control policies at Mackie. The defect is so severe on this unit I have here that just placing a small pressure at the side of the op-amp chip separates it from the board. The problem affects all components on the EQ board. All the EQ boards(16) were in different degrees with this defect. If you really want to see some more pics showing the severity of the defect I will post them.

I am not an audio engineer or a recording 'techie'. My area of expertise is in analog circuits with many years of failure analysis. I have been working in this field for 35 years. In my business this is grounds for a product recall without time constraint. Mackie did not disclose this defect to my friend when contacted via phone even though his symptoms would not suggest ribbon cables as the source of the trouble described. Instead they sold him a box of ribbons for $180.

Acidman - it sounds as though your Mackie board needs a service. Where in the UK are you located?

I am finding Mackie products (and don't get me started on their Tapco stuff - it took me over a year to establish a recall-worthy fault on 4 Juice power amps and eventually have the fixed and re-warrantied) worse and worse made the more of them I see - quite contrary to their marketing. I have a good repair guy who retrofits VLZ desks with gold pots and better faders; he might well take on a 32:8 so if you need his contact details let me know and I will dig them out.

Hi Boswell, I'm way way down south. Anyway have now discovered the problem..........FADERS ! They should be 10k ohms and one of dodgy ones is OC right near the bottom compared with a good one.
However, getting the right one is proving a bit difficult. Mackie put me in touch with some of their service agents here in the UK and none of them really had a clue. I know they are ALPS faders and I'm pretty sure they are
STRSAON05's 10k 100mm logarithmic. Finding someone who has one in stock is hopeless (every model but !!!) :mad:

Oh and thanks for the offer Jeemy but the desk is allready in 43,781 pieces (ish) and don't plan putting it back together till it's fixed( can't imagine why :rolleyes:). Unless your guy can find some suitable faders that is.

I'll ask and see mate.

*** Note: In a private message I have advised ACIDMAN that I have some scrap bords to pull parts from. I thought it best to gain the experience of the forum and post my response as public.

ACIDMAN, I will believe you have experience handling and soldering these type components but if you have any questions about compression-contact film materials just ask... before you try to figure it out yourself. (I and others have already done that and paid the cost). If you have no experience with this type material I urge you to find someone who has. They damage easily. Too much heat for too long will give you one more of what you are removing from the board you have. If you were not aware of that it may explain why yours are failing. The leads are fragile and will break off if bent even once. I am curious about how yours came to fail. The items I have here provide a 10K between the single lead and the interior lead of the two at the other end. If you can read a steady, non-changing value of 10K to 12K between these two leads you likely don't have a problem with the pot. The Mackie schematic for this fader ckt shows the fader resistor connected between audio common and the channel audio with the fader wipe going to a buffer amp and the direct out. What you describe would suggest the interior lead is what's open and that would indicate there was either physical damage to the pot or its possible the buffer stage has lost its feedback signal and is saturating until the fader pot hits signal common. If you can't define this with confidence I urge you to drink a glass of water and get another look at the board. Without physical or severe electrical stress I would not expect a pot that was working to just decide that one day it would not. Three of them is a clan rebellion.
If you are sure these replacement faders will resolve your Mackie’s trouble give me and address and I will get them out right away. If you have a PayPal account we can resolve the cost through them, if not you can just mail me a check/money order for the $10 and shipping.
Shipping cost can be determined at this link; [[url=http://[/URL]="http://pe.usps.com/…"]http://pe.usps.com/…[/]="http://pe.usps.com/…"]http://pe.usps.com/…[/] and after looking at the fees I expect the flat rate small box would do well @ $13.95 but you decide what you want. The cost increases quite a lot for insured or express packages. The pots weigh ~5.5 oz /3pcs. With packaging it will be ~16 oz. With the flat-rate the limit is 64 oz so I can put some wood pieces in to keep it from damage when it is loaded in the airplane under the compressor my neighbor is sending to your neighbor.