Rebuilding a 1989 Mozart -- Sharing My Progress

Graham Langley founded Amek in 1973 with Nick Franks. Since then, AMEK and TAC recording consoles have been the choice of demanding audio professionals for over 25 years.

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Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 12:16 am

I've been working on a Amek Mozart 40 Project for a while now. Only a few people I know care about this sort of thing, so I thought I would share it with you guys.

The console was purchased from a Craigslist ad, as a fire sale. It was abused, and not maintained, just rigged to work as time went on. At some point there was more wrong with it than the original owner wanted to deal with.... Power Supply was failing on all accounts, and the -17 rail went unregulated and spiked to -33 volts, so it cooked a bunch of the OpAmps and other components prior to my getting it… There were a lot of sticky drink spilled in lots places, that caused catastrophic shorts... The group computer was not functional, only because the group distribution card was soaked in soft drink spills throughout the fader plates...... Shorted a mess of 4000's logic chips.

I love old analog consoles and enjoy working on them. I hope someone enjoys looking at what I doing with it, and maybe could inspire me with some ideas... Maybe with some of what I have done, someone out there could also get inspired, or at least share some ideas on ways to overcome the challenges of this project.
roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 11:04 am

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roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 11:12 am

The first four photos are the console as it was when removed from the original owners place.

The console was very dirty. Layers of grime built up from years. Including smoking. I am not sure if the white powder was sugar from a pastry or drugs.... I didn't want to find out either. Many of the switches where frozen and most of the knobs where hard to turn. A few broken faders. All of the faders modules where pressed down in the middle and bent from people leaning on them.
roadbear
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Posts: 52
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Location: Nashville, TN USA

Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 11:26 am

Removed every module. Disassembled each, down to removing the IC board from the plate and face plate. First cleaned each IC Board with a spray Electronics Wash. Some of them I sprayed 91% rubbing alchohol on and brushed through the drink spilled, which had gotten under chip sockets and really gummed up some areas. When all of the sugary grime was removed, then I rewashed with electronics cleaner, and compressed air.

Once each IC board was clean, I then cleaned and lubed every pot and switch. I posted in another topic about how I cleaned these. Here is the link.

http://forum.analogconsole.com/viewtopic.php?f=1&t=6910#p15151

At this point, I had not powered up the console, and I didn't know which pot and switch was bad or good. I just did them all, hoping for the best.

Then for the cosmetic part of the job. I soaked the knobs and switch caps in a cleaner called "Mean Green". That is magical stuff for getting dirty grime and smoking residue off. Sprayed the face plates down with it too. I was glad to see that everything was still looking good under all of the dirt.

After several weeks of working after hours on this, here is what it looked like after the cleaning.

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roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 11:39 am

I tried to clean the fader plates. No joy. Many had the lettering rubbed off from use, or from cleaning it with alcholol. They had stains that no cleaner would remove short of sanding on them. I decided at that point to see what was under the original paint, so I stripped one and sanded it down to the bare aluminum.

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I thought it looked really nice as bare aluminum, and maybe do them all that way, and get them rescreen printed.

But then also thought about making it look like it did originally. I took all of the fader plates, including the blank filler panels down to a local powder coating shop and had them strip and refinish them with a color very close to the original color. While the plates where being refinished, I started working on the electronic problems.

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roadbear
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Posts: 52
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Wed Oct 22, 2014 12:09 pm

Power Supplies are usually easy to work on, but the MPS15 is heavy and big. I like that it is modular and parts can easily be swapped for testing. The unit I had was obviously hacked around on.

I also like that each rail is separate module, and each can STILL be purchased new, even after 20 years. These power supplies are made by International Power Model IF15-15. ($240.00)

http://www.mouser.com/ProductDetail/International-Power/IF15-15/?qs=0xCm9DOQnC6i1A%252bT7548Eg%3D%3D

Amek used these 3rd party power supplies in their own case design. They had to change only one resistor to a different value to get it to regulate 17v instead of 15 volts. Smart.


The +17 v rail was dead, and ended up being TO3 recitifers as the main problem.

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Each of these makes up one half of a full wave bridge diode. Smart to make them fit in a TO3 case, but now these parts are hard to get. I just subbed both of them for a standard bridge rectifier and mounted it to the case. I had seen this done in these PS's before. It is also much easier to service later, since it is now easy to swap and get at.

Here it is working correctly after a good cleaning.

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On think to note at this point. I adjusted the regulator to +-17.5 unloaded on the test bench. Meaning, while the console was NOT hooked up to them power supply. After the console was eventually powered up, the regulators had to be increased to get +-17v at the console due to the voltage drop across the wires and the load being placed on it. They tested around 15.3v until they where cranked up. Then, under load, it was obvious that all of the DC Ripple filter caps where not able to hold up. Once I pushed the voltage past 16.9 or so, I could see each slowly start dropping off and getting erratic. Also, I could feel the heat increase from the power supply. They would not measure a stable voltage. Also, i could hear 60 cycle hum on the stereo outputs on the console. the hum would decrease in level, as I pulled out modules in the console. Once I pulled out enough modules (more than half of them), the voltage started to stabilize, and the hum almost went away. DC Caps replaced. Problem solved. I had to wait around for the Caps to arrive. They had to be the exact caps, because they had to fit exactly in the space. Expensive, but required.

I
roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Fri Oct 24, 2014 2:54 am

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This cap still looks nice.... but it is BAD, just like the other 5 that match it, in the +-17 ps modules.

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View with the heat sinks off of the +17v power supply module during testing. It is somewhat scary to work with this much amperage. I am messy and clumbsy, so I had to be extra careful not to short anything while it was all opened up.
roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Fri Oct 24, 2014 3:01 am

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Outside sanding the old finish off of all of the wood parts. All the way down to the wood.

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This is after 2 coats of polyurethane mixed with stain. I changed to color to go a little more in style for this decade. Filled in all of the screw holes that the previous owners put in them with wood filler. Can't even find them now. It will have a total of 4 coats when it is done.
roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Fri Oct 24, 2014 3:29 am

The frame had a lot of the same paint problems that the fader plates originally did. The finish would not clean, and had a lot of sratches in the finish. I decided it would look better to sand the old powder coat/paint off and leave it bare metal. I don't know how resistant or durable it will be in the long run, but it sure looks better as bare metal than it did with the old paint on it.

I entertained the idea of removing everything from the frame that wasn't welded on, and taking the entire frame down to get powder coated. I would have had to rent a truck, and convince my friends to come help me move it again..., and then the expense. I decided NOT to powder coat the frame again. To much trouble... Almost everything that shows on the frame while it sits in the studio has been refinished in some way anyway. It wasn't worth it.

I started sanding the center span that separates the center section from the channels 1-24. I had to remove all of the modules and center section pieces, and them cover each area with a large painters cloth to keep the sanding debris and dust out. I also taped over the top area where I wanted to sanding to stop. I didn't want sand past the top edge. I hand sanded with progressively finer grits going the long way so the sanding grain went the long way.

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I liked it so much, that I went ahead and did most of the visible part of the frame. The flat part on the frame below the patchbay was also very scratched up, and rusting in the exposed areas, so I sanded it to.

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Then continued up the edge on both sides of the patchbay.

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And then finally the other side of the console edge. It was the most gouged up. It looked much better as bare steel.

I added back the cheeks and wood trim, to get a sense of what the colors looked like against each other. It is very different from the original color scheme, but I like it better like this.

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Next, I sanded one of the front fader trim pieces (long metal pieces that cover the lower screws of the fader supports) down to the bare metal too (these are made of aluminum, not steel). Then, I sat one of the re-powder coated fader plates against it to see what all of the colors looked like side by side. I think it looks pretty cool. Added a few channels modules to the shot. Looks new again, but new like original.

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roadbear
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Re: Rebuilding a 1989 Mozart -- Sharing My Progress

Postby roadbear » Fri Oct 24, 2014 3:54 am

At some point during all of this, I decided to remove and paint the meter bridge. It was scratched and dented, and bent, and needed some help too. I was thinking that it would look cool as a metalic aluminum color, to continue the metal theme up to the top of the console.

I removed the meter bridge metal frame, sanded it, and spray painted it with aluminum spray paint. I looked great by itself, but NOT so great on the console. It looked pretty stupid.

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(Side Note: As you may have noticed in the photo above, I also removed the archaic floppy drive and replaced it with a USB Card Reader, USB HUB Device from ebay. I plan on making the Amek Center Keyboard and the trackball work with my Mac computer and control my DAW right from the console. This USB device will aid in that goal, and makes that "hole" in the meter bridge somewhat useful again. )


I removed it again, and sent it to powder coat. I knew the color I would have to pick from in their color book would probably not match the original color exactly (same color as background of channel modules). I hoped it would be close enough. It would certainly better than the stupid metalic paint.

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The color came back very close, and looking really nice. Much better than both the original and the spray paint. Powder Coat is better then spray paint anyway just for durability alone. It was a good decision.

Notice, that by the time the meter bridge returned from powder coating, I had a lot more of the console actually working too.
roadbear
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Posts: 52
Joined: Fri Jan 25, 2013 3:43 pm
Location: Nashville, TN USA

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