MCI JH-416 Story...

  • Thread starter Thread starter sweetbeats
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So, "terrible" but promising with a bit of TLC and usage, I gather. That sounds okay to me!

How are the summing amps on the 416? That would be key to getting great mixes, if they're clear and open sounding. One of the things that was always a bit on the cloudy side to my ears with the TASCAM boards I had used. I would expect, (hope), the MCI to be of a much higher standard in that regard.

Cheers! :)
 
I'm not sure if this link will be any help:http://www.teletech.ca/ttmain/31358.html

Its a JH416 a shop by me has had for sale for a while. I have to pop in there to pick up a manual off of Patrick (tech who has been in the biz for a while... I think Teletech were MCI dealers back in the day so he knows quite a bit) - so if you wanted pics of something I'm sure I could snap some and send the over.

Mike
 
The Ghost of FM said:
So, "terrible" but promising with a bit of TLC and usage, I gather. That sounds okay to me!

How are the summing amps on the 416? That would be key to getting great mixes, if they're clear and open sounding. One of the things that was always a bit on the cloudy side to my ears with the TASCAM boards I had used. I would expect, (hope), the MCI to be of a much higher standard in that regard.

Cheers! :)
Click to expand...

"Terrible" as much as expected considering age, disuse and neglect...more than "promising"...I think its going to hit my like I was hit the first time I heard audio through one of the amp channels on my Ampex MM-1000 which was an uncontrolled "no way!". Some TLC, replcae/upgrade the caps and either service (near impossible), replace (challenging) or bypass (easy) the relays and conduct some other mods (mostly around the relay bypassing, and experimenting with building discrete opamps) and I think its going to sound nothing short of amazing, head amps, line drivers and summing amps...I love the idea of the stepped EQ. Its not for everybody I realize, but no wipers and resistive elements to deal with.

Again, this console would not be for the "transparent" crowd. The trafos are big...its not going to sound like a transformerless board. But Its hard to argue with the clean and simple signal path. You look at one of the Input Module PCBs and you think "wow, that's pretty sparse looking" and THEN remember that PCB includes not just the input, 4 auxes and 4 main outs, but *also* includes 16 subgroup outs AND a buss return/summing amp...here's another look for those that don't want to go way, way back in the thread:

IMG_0109_11_1.JPG


That's a single-sided PCB...everything you see is all that's involved in the three inputs (MIC, Buss summing return and tape return) and a total of 25 outputs including the SOLO buss.

And I had to have somebody walk me through the theory to really understand how the voltage amplitude of the audio power rails is *directly* tied to headroom...typical audio rails are +/-15V, so a total 30V swing. "High Power" rails today are usually +/-17V, mmmayyyybe +/-18V in some cases so 34V-36V swing. The JH-400 consoles are +/-24V audio rails so 48V swing. Headroom...gobs of it. As was conveyed to me by a friend recently, "There's no substitute for higher voltage rails in a console; it's the only way to get extra headroom...Opamp consoles running at +/- 15v rails can't compare unless there are step-up audio transformers throughout, ala API."
 
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man-bot said:
I'm not sure if this link will be any help:http://www.teletech.ca/ttmain/31358.html

Its a JH416 a shop by me has had for sale for a while. I have to pop in there to pick up a manual off of Patrick (tech who has been in the biz for a while... I think Teletech were MCI dealers back in the day so he knows quite a bit) - so if you wanted pics of something I'm sure I could snap some and send the over.

Mike
Click to expand...

Hey, thanks for the offer Mike. I think I'm set...I did look at the pics and description of that JH-416 though...its a 416B so the input modules are significantly different from mine. $10K? *gasp*

I think that may explain why it has been for sale for "a while". :)

That's a bit rich for a short-loaded 416B that needs some TLC. Check this one that sold from Blevins in fairly recent history...totally gone through by Randy himself, recapped, fully loaded frame and sporting the light meter bridge for $8K:

MCI JH416A

I'm curious about the detail in the listing for that Teletech 416B as it says there are three supplies and one is the 48V phantom supply. That means one of the standard 24V supplies is missing. There are 3 supplies standard but all 24V bipolar: one for audio, one for the relays, and one for the lamps. If one of the three on that 416B is for phantom power then it is missing one of the three proper 24V supplies... :confused:

Thank you for putting up the link...I love seeing pictures of different JH-416 consoles. There is always something curious to look at. :)
 
The Motherboard Is Extracted...

Well, that was literally one of the most hair-raising audio equipment repair related activities I've ever had to do.

I present to you, the MCI JH-416 motherboard:

IMG_0671.JPG



It was hair-raising because I had NO idea the assembly was as heavy as it is. I mean, I knew the transformers would have some heft to them, but I guess I just didn't consider the cumulative weight of all 72 of them. I'll have to get a scale out to the shop but I estimate the motherboard assembly weighs around 80lbs.

The motherboard is actually two separate boards (which is one of the issues with these consoles as the trace links between the two boards eventually fail) mounted to a wood frame which is all screwed to the metal pan of the mixer frame. Even though the PCBs are mounted to that wood frame, with the mass of the assembly and the length it is floppy. I had to be very careful how I held it; where I grasped and the orientation I maintained to maximize the sheer strength of the panels.

The PCBs are made of glass-fiber type material which is good. I literally don't think it would have been possible to extract the assembly from the frame without serious damage to the PCBs if they were the phenolic type.

Why remove the motherboard assembly?

  1. Cleaning of the motherboard assembly AND the mixer frame
  2. Repair/upgrade of the board-to-board trace links
  3. Repair of the mixer frame
  4. Reversion of a number of janky mods/work-arounds that have been added during its life
  5. Properly address the root cause of the "work-arounds
  6. Solder up hundreds of feet of new wiring harness

Here's the empty mixer frame before I removed the motherboard assembly:

IMG_0666.JPG


IMG_0665.JPG


IMG_0667.JPG



And here it is after the motherboard assembly was removed:

IMG_0672.JPG



Where'd all the modules go? I rigged up a simple hanger board...makes it easy to get to the modules onesy-twosey as I'm doing a lot of research work related to identifying mods that have been done, repairs that need to be executed, selection of components for recapping, and development of a discrete opamp.

They are there behind the white sheet:

IMG_0669.JPG


IMG_0670.JPG



Also, just had to satiate my curiosity about one of the VU meters...these are Dixson meters, same as is found on all the Ampex AG-440/MM-1000 electronics, but these have "MCI" screened on them. Rare. A couple of the meters have busted glass, and one of them the needle was stuck midway. I was worried it was toast but hoped it was just broken glass binding the needle, so I took it apart to too see.

Love the look of the meter bridge:

IMG_0668.JPG



Here is the meter of question:

IMG_0673.JPG



And the happy result...meter is okay. I have some glass that I cut for another project years ago so at some point I'll get the meter cleaned up and install the new glass.

IMG_0674.JPG
 
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THAT...is cool, Jeff...symbolic.

Minor detail, there are two lamps per meter; bulbs down in the lower corners. I can pull the lense off and put a pic up of the bare meter so you can see the locations if you care to. I'm not expecting or desiring you change anything, but I just know you are a stickler for those kinds of details.

How did you get that charred effect on the image? Very cool. And I'm always impressed with your ability to create and manipulate light in your work.
 
sweetbeats said:
THAT...is cool, Jeff...symbolic.

Minor detail, there are two lamps per meter; bulbs down in the lower corners. I can pull the lense off and put a pic up of the bare meter so you can see the locations if you care to. I'm not expecting or desiring you change anything, but I just know you are a stickler for those kinds of details.

How did you get that charred effect on the image? Very cool. And I'm always impressed with your ability to create and manipulate light in your work.
Click to expand...
Thanks for the 411 on the dual bulbs! I suspected that might be the case but went with my old faithful lighting effect preset that I built in Photoshop. Shouldn't be too difficult to turn that into a two bulb effect. ;)

About the distressed effect, that involves about 40 or 50 different tweaks of the color lighting and detail...a bit too complex to properly detail all that out. But I just wanted to go for a lost relleck look with a glimmer of hope as to what it once was and what it again can be with a lot of TLC on your part. :D

Cheers! :)
 
That's pretty sweet...I wouldn't understand the content of a complete dissertation on what you did, but the results are dramatic.
 
A little experiment...I pulled off the saddest switch caps I could find, one of them so worn the center is cracking.

Cleaned 'em up as well as I could and am trying out something to restore the white lettering.

Before:

photo%20(2).JPG



After scrubbing:

photo%20(1).JPG



After rubbing them with a white crayon...am concerned about getting waxy stuff over the rest of the mixer long-term:

photo.JPG



I'm resigned this mixer is always going to have a well-loved look to it.
 
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^^ That looks pretty good! :)

Maybe putting some type of sealer over the top of the waxed in letters, something akin to what is used for lady's nail hardeners? Or instead of crayon wax, perhaps an oil based paint where it can be wiped off the upper surface while leaving enough of it in the recessed lettering channels? I'd assume that might be the more resilient approach?

Cheers! :)
 
Print some new ones, that is what I did for missing switch caps that are impossible to find.
 
@ Jeff, good idea on the clear nail polish...I'll try that!

@ Mdainsd, "print" them? From what type of printer and on to what medium? Labels?

If there was a method that looked factory I'd be interested, but I don't want it to look like stickers on the switch caps.
 
No, a 3D printer. Make complete new keycaps. I had a thread somewhere around here where I went over making new transport keycaps for Sony apr-24 remotes.
 
I rrrreally don't understand the whole 3D printer thing. I'll need to do some studying of it to grasp it.
 
sweetbeats said:
I rrrreally don't understand the whole 3D printer thing. I'll need to do some studying of it to grasp it.
Click to expand...

The 3D printer would cost far in excess of what the buttons would cost and you'd need to draw up 3D data files on each one in order for the "printer" laser cutter/ mini CNC machine to carve them out. plus, they'd still need to be painted. So...not extremely viable unless you know someone who has the equipment and can do up the data files for you.

Cheers! :)
 
That isnt necessarily correct information. There are many small house places now doing quick turn around 3d printing. Its printed, not machined. Its cheap. You can specify the color you want them printed in in many cases. What you will need is someone to use a pair of calipers and get good measurements off of an original switch cap. go to a 3d cad program (I use SolidWorks) and create a step file which any print shop can use.

Corey. if you want I will do the cad file for you, but you will have to trust me with a cap to do it....

*edit: if you have lots of caps to do with different legends on them a possibly cheaper route is have the print house turn out blanks, then as you need them go to a trophy or engraving facility that does those plastic tags and have them engrave the legend you need.
 
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