Mackie 1604 VLZ caps wow

[fazer]

So I have a 20 yr old 1604vlz mackie mixer given to me (in box hardly used. ) I set it up in the jam room and notice problems with buzz from phantom pwr on some channels. Pwr supply has numerous caps in all locations that need replaced. I fix them and decide to check/replace the pin2 pin3 dc blocking caps in the i/o board s. They are buried under the xlr jacks and all have high dcr /esr. Or no indication on my meter meaning there dead/open. Do you know how many caps there are in the channel main board. There all bad. No wonder so many people hate mackie (or love them if the caps are a good batch).
What a daunting exercise to repair. Not sure I’m going to fix this thing. Might take 100 years. I’ve only got 20 left.

 

[fazer]

Some pics. It’s doable but what’s my motivation? I guess I get a serotonin hit when I get something repaired. Gonna turn into a summer project.

 

[fazer]

https://groupdiy.com/threads/mackie.80879/
Service manual 1604VLZ

 

[Bo Deadly]

The Mackie mixers are not designed to be serviced. It is far more cost effective to simply purchase a new one. The ones made by Loud Technologies with higher numbers of channels have CFIA preamps, ground cancelling sum buses and features that make a very respectable small format mixer. A new 1604 VLZ4 is probably a couple hundred bucks. VLZ3 are also good and even cheaper.

 

[JohnRoberts]

Mackie was very successful at being inexpensive for the perceived value of the features. A combination of value engineering and over the top marketing. Designing stuff to be cheap to build is not the same as designing it to be cheaply repaired (trust me I worked at Peavey).

The performance of the mackie when working properly will be OK, but by now the electrolytic caps are a little long in the tooth.

A little work replacing the old tired caps is good training.

JR

 

[user 130681]

Never replace components because they are old but otherwise perfectly serviceable. That is a folly and most people replacing them cause more "faults". (Not suggesting you will).

Replace faulty componens only and most components cannot be accurately tested whilst still on the board.
The 48volt supply is the likely cause of your hum, due to the constant voltage regulator having a short circuit. Power supply fault ... as usual. Q1 & Q2. There is no over current protection!
An easy fix.

 

[Khron]

Unless the input caps are domed, i'm not sure i would worry about them. NRSA is a series from NIC Components, i believe? Which aren't (or shouldn't be) quite bottom of the barrel to begin with.

But phantom power hum is unlikely to be caused by the input DC blocking caps.

 

[fazer]

The 48v power supply was the main cause of hum as suggested. The dc blocking caps that show high esr when pulled and tested out of circuit test at less than 1 uf. Should be 47uf. Traces on the PCB are small so main thing is to not damage the board. I would probably not repair one of these again as Bo deadly suggest. They are not designed for that. Just seems sad to throw them away.

 

[living sounds]

I've once completely recapped an old 1202 with quality caps, replaced the EQ caps with Wima and polystyrene and changed the op amps to 5532s. PSU gets hot, but it does sound really, really good, especially the high frequency EQ is as good as you can wish for.

 

[JohnRoberts]

The 48v power supply was the main cause of hum as suggested. The dc blocking caps that show high esr when pulled and tested out of circuit test at less than 1 uf. Should be 47uf. Traces on the PCB are small so main thing is to not damage the board. I would probably not repair one of these again as Bo deadly suggest. They are not designed for that. Just seems sad to throw them away.

Mackie used double sided PCBs which are more robust than cheaper single sided PCBs (like Peavey used). You should be able to rework/repair using properly sized iron (too much wattage can easily lift traces). The plated through holes can make removing through hole components a little more difficult but it is an acquired skill accessible to all of us. Get a working solder sucker to remove as much solder from the leads/holes as possible.

[edit- if removing old caps it might be easier to cut them off the board carefully then desolder the leads one at a time /edit]

JR

 

[Bo Deadly]

Being an older model with through hole parts, it is possible to service it if you really want to and it's just time. You might get some satisfaction out of it. Especially if you have a hot air station. The hardest part is probably just dissassembly and reassembly because you have to literally take the whole thing "to bits" just to fix one part. With a newer model that uses SMD, service would be much more difficult and simply not worth the time seeing as how there are piles of new models on Ebay for cheap.

In 2020 I got a 1402-VLZ4 for $180 USD on Ebay which is a pretty great deal for what it is. I tested noise and THD of each channel extensively and found to it work exactly as expected. The best bargains are ones where people perceive the value to be less than it is. If someone mocks me for using a VLZ4 I can bust out the schematic and explain to them exactly why they're wrong.

Everyone mixes digitally now so there isn't a really strong demand for large format mixers anymore. But the small format mixers are great for creating sub-mixes for different people. For example, if someone has a bunch of keyboards and sequencers and pedal effects and so on, they can have the knobs needed to dial up the sounds they want and be creative and then send only two or four channels of dry and wet to the converters.

 

[JohnRoberts]

Being an older model with through hole parts, it is possible to service it if you really want to and it's just time. You might get some satisfaction out of it. Especially if you have a hot air station. The hardest part is probably just dissassembly and reassembly because you have to literally take the whole thing "to bits" just to fix one part. With a newer model that uses SMD, service would be much more difficult and simply not worth the time seeing as how there are piles of new models on Ebay for cheap.

In 2020 I got a 1402-VLZ4 for $180 USD on Ebay which is a pretty great deal for what it is. I tested noise and THD of each channel extensively and found to it work exactly as expected. The best bargains are ones where people perceive the value to be less than it is. If someone mocks me for using a VLZ4 I can bust out the schematic and explain to them exactly why they're wrong.

Everyone mixes digitally now so there isn't a really strong demand for large format mixers anymore. But the small format mixers are great for creating sub-mixes for different people. For example, if someone has a bunch of keyboards and sequencers and pedal effects and so on, they can have the knobs needed to dial up the sounds they want and be creative and then send only two or four channels of dry and wet to the converters.

I was in the trenches competing with Mackie so I hold them is somewhat lower regard. IIRC I think one problem I discovered with the 1402 on my test bench was that the insert point was not buffered. If you patch into that insert with a modest source impedance (like 600 ohms) there is a clearly measurable frequency response interaction with the Baxandall channel EQ. The input impedance of the Baxandall topology changes with EQ setting. I discovered this by accident when switching the source impedance of my test bench between 50 ohms and 600 ohms.

This is not a huge problem and most people will never notice but it is one of the corners cut to deliver that feature set for that price.

JR

PS; Small format mixers are generally easy lifting for sum buses.

 

[fazer]

I have a hakko fr 300 desoldering tool. It works well to add solder then melt and suction . I’ve repaired focusrite this way before but took a 3year covid break. Put on some music and work patiently.

 

[JohnRoberts]

I have a hakko fr 300 desoldering tool. It works well to add solder then melt and suction . I’ve repaired focusrite this way before but took a 3year covid break. Put on some music and work patiently.

you could also use some liquid flux, but solder is handy.

JR

 

[fazer]

I have flux I’ll try that. Thanks

 

[JohnRoberts]

Solder-wick which is wire braid with flux embedded is the gentle but expensive way to remove excess solder.

[TMI] I recall back in the 60s before solder wick was invented, as a junior technician we would use stranded wire dipped in liquid flux, to draw (wick) excess solder from joints. [/TMI]

JR

 

[KRiSh05]

I recently bought a Hakko FR-301. I am replacing all sliders and 2 tactile switches in a Mackie 1402 VLZ MicroSeries made in USA. That mixer did shitload of raves in the forests took humidity was badly stored with half rusted panel. It still worked almost perfectly. I think they deserve servicing. Right tools give ways to do it. the unit i have only has a problem with Right Master channel having lower volume than the Left. I will try to debug it after completing sliders and tactile replacement. Yes they are not designed for easy service. But it is doable. I dont have SMT desoldering experience not tools and resistors are very small. Hope its some THT capacitor or it will be hard or impossible for be to fix that issue if it is on SMT parts. I will do a post on that issue when i go to it.

 

[fazer]

Its repaired and working. The power supply had numerous bad caps for phantom and +/_ 16volt tired caps. The pod board had mostly problems with the 47uf/25v coupling caps around the preamp out with caps that had high ear and low cap values. Glad I had a Hakko solder sucker. Its back together and sounding good or at least better without the noise on the phantom channels. Yeah! not sure I would do this again but there is an dopamine fix when you bring something back to life.

 

[user 37518]

Back in 2014, a great friend of mine was going to get married, since all of his friends are musicians, some of them were going to play live at the reception. He owned an old Behringer mixer which they were going to use for this purpose, but it didn't work. My wedding gift to him was replacing all the caps and cleaning all the pots/faders. I think it still works till this day...

 

[emrr]

Flashback:

https://groupdiy.com/threads/fun-with-paralleling-film-caps-in-a-mackie-console.28451/