8 Bus VU Meter Replacements

[Dreamsequence]

If anyone following this forum is using their HDR/MDR/SDR with a Mackie 8 Bus console that needs the VU meters or the lamps replaced in their meter bridges, check my post on the Mackie UserGroup site. I detailed where the meters can be purchased and/or LED replacement lights (watch DC polarity!).

[DrUmSenstivie]

I've tried but didn't succeed. My VU's just died on me, the left doesn't move, the right has a broken pin. I really need help fixing them...

[Bruce Graham]

Hey guys;

There are 2 lads who may be able to help both of you.

One is Eric Russ, he has pasts for both the d8b and HDR/MDR/SDR.

The other is Mike Rivers. He helped write the HDR Manual for Mackie and has his own publications on the HDR/MDR.
He is also on this forum.

If you can't get them let me know and I'll get you their email address's.

Good luck
Bruce

[Bassplayer]

Do you have an email or contact for either of these guys? I'm in need of a VU meter for a Mackie. Cheers.

[Dreamsequence]

Gents:

I posted a detailed description of how to replace your 8 Bus VU meters on the now-defunct Mackie Users Forum. Luckily, someone was able to find it floating around on the net and snagged it. I found out who manufactured the original meters, and found a distributor that will sell retail. The difference is the meter faces will not say 'Mackie', and they use amber LEDs instead of the incandescent bulbs that get really hot and eventually burn out. Not so with the new meters. The amber glow is kinda cool...

I'll see if there is a way to get it in the d8b database. It's pretty long but is step-by-step. In the meantime, PM me if you want the instructions and vendor information. I might even have a pair of the new meters in my shop.

Pat

[Dreamsequence]

Bassplayer:

JLM Audio in Australia has the meters. SEW ST-475. They fit perfectly, but there are a few things you'll want to know before you tear into the job. The instructions are below. I do have (2) meters available; PM me if interested.

PLEASE READ THE ENTIRE POST BEFORE STARTING UNLESS YOU'RE AN OLD HAND AT THIS STUFF. I've written this for the novices out there. I wanted to do a step-by-step with pictures, but couldn't get directions or clearance from the forum moderators. So, here goes:

- Go to JLMaudio.com. They are in Australia. While you're on the website, check these guys out. They are awesome audio fanatics, especially for the DIYer.

- Under VU meters, select the SEW ST-475. These are nearly identical to the originals; in fact, no one remembers at either end, but I believe SEW manufactured Mackie's meters. Physically, the case, terminals, etc. are perfect matches.

- There are a few differences: the ST-475 has a yellow dial face, but when you replace the pair they look cool, kind of retro like a Neve console. They also have yellow LEDs for illumination (AT LAST), but read on for a wiring modification.

- The only negative is that the ST-475 uses (2) diagonal screw studs for mounting; Mackie uses a thick layer of double-stick neoprene tape or foam. You'll discover immediately that the meter must be completely removed from the exterior housing, exposing the needle to damage. Leave the cover on as long as possible, or be very careful with it. One of the studs can be removed by backing it out of the backplate, but the other is behind the dial face. JLM recommends using a sharp diagonal cutters and snip it off close to the backing plate (USE CAUTION TO AVOID SHOCKING THE METER MOVEMENT or crack the plate). The second choice is to drill a hole through the aluminum mounting plate, but depending upon how you remove the old meters, you'll find this is harder to 'spot' the meter alignment on the mounting plate. The former method affords more room for error when you go to mount the meters.

- I assume you know how to remove the meter bridge; if in doubt, check the Mackie Technical info for installing the bridge. Most users remove the small self-tapping screws that hold the brackets to the housing, and that's a great short cut. However, it is easier to reinstall if you assemble it completely and follow the instructions on installing the pivots and trunions. NOTE: the pivots are supposed to have a small anti-rotation pin in the inside end; many of these get sheared off by someone being over zealous with moving the bridge back and forth and the trunion is too tight. That's why many of the bridges won't stay put and the screws cannot be tightened any further. The bridge reassembles with less cussing when you try to attach the end brackets if you do it this way.

- After carefully removing the ribbon connectors, the bridge can be moved to your favorite workbench, kitchen table, etc. Use your fingers, a tweezers, or a gentle touch with a needle nose pliers to pull the gray Select button straight up; it will easily press back on later. Remove the right mounting bracket and carefully slide the Lexan meter face off to the right. It may fight as the meter shield and the caps for the meter adjust colide; be patient to avoid damaging the shields.

- There are (3) TINY gold jumpers connecting the VU board to the rest of the LED bar graphs (E1, E2, E3). Very carefully remove AND DON'T BEND THEM UP or lose them. These convey the Source/Tape selection to the rest of the bridge metering.

- One of the hardest parts is rolling / folding the VU ribbon cable up inside the housing, as it must be slid out of the housing with the meter backing plate. The only suggestion I have is to be patient and observe with a flashlight what the available room is between the meters (that's where it attaches). Be nice to it because you'll need to reverse the process to reinstall the meters. The one thing I do recommend is to gently wrestle the dust cover off the cable- no way you'll get that squeezed in between the meters with the cable.

- Note how the meters are mounted w/ the neoprene tape. If you were able to break the adhesive bond (razor blade), you might be able to reuse the old tape; otherwise, a trip to the hardware store is in order. I recommend you replace one at a time so you get the feel of how to orient the meters on the mounting plate. That tape is plenty sticky, so kluge up a shim arrangement as a template or guide.

- While you're at it, examine the heat damage from the old incandescent lamps to the PVC meter shields and the back of the Lexan meter face. I rebuild the shields with some heavy MILSPEC aluminum tape, but you'll have to be creative. Remember: the shields need to maintain their postion relative to the meter face so the Lexan cover can be slid back over the meters.

- I use some Gloss Black Testor's model paint with a foam applicator to 'touch up' where the black mask has been scorched off the back of the Lexan cover. NOTE: do this where you can see through the cover; it could take more than one coat of paint. The repair should be invisible.

- Note the terminals on the old meters; after soldering, you'll need to bend the new ones to match or they might short out on the back of the housing (although there should be an insulator on the back of the housing), or at least give you a hard time sliding it back in. The meter input wiring is the same polarity as the originals. Go ahead and re-solder the same. HOWEVER: THE NEW LEDs ARE POLARITY SENSITIVE, SO READ CAREFULLY- one of the meters can be wired straight up (Black and Blue wires), but the second one will have to be re-wired to get the polarity correct. My notes read: Left meter (E8) Blue is +18 VDC, (E9) should be Black (- side), (E10) is Black (+18 VDC) for the Right meter, and (E11) is the (- side of the right LED). So, (E8) & (E10) should connect to the + terminal for the LEDs on each meter. If you trace out the circuit, or better yet, take a few DC readings before you rip the whole thing apart, you'll be able to trace this out. I found it easier to reverse the Black and Blue wires at the PCB on the reversed meter LED because the wires were too short to reach over the meter. When finished, the meter LEDs are wired in series with +18VDC sourcing (2) 12 VDC LED banks. The illumination is fine and current draw is in the healthy range for LED life expectancy. AND NO MORE BURN-THROUGH.

- NOTE ON REPLACEMENT LIGHTING FOR EXISTING METERS: JLM also offers an LED kit for existing meters, choice of blue or white (there's a choice on the order page). There are several other kits on ebay in varying colors. Remember the same rules apply to polarity when replacing with LEDs. The old lamps didn't care about polarity.

- If you've gotten this far, the meters are wired, terminals bent in place, shields repaired, Lexan cover repainted, meters aligned and centered on the mounting plate with sticky tape (use high quality neoprene tape; that's what holds the meters in place). If you want to test your work, plug the ribbon cable in and rest the meter plate on a good insulator. When the console comes up, you should be able to send some signals and check out the cool LED lighting.

- Reverse the process; getting the ribbon cable back through the housing is the worst part of the process. Carefully reinstall the (3) gold jumpers. At this point, I plug the ribbons back in and test the LED bar graphs. You'll note every bank of (8) has a set of those jumpers. Make sure they are all secure. If the meters haven't been tossed around, they should rest at the end of the scale in the same place (one notch below -20dB). If not, and you know how to re-zero the meters, do it now. If not, DON'T MESS WITH THEM. Just prior to sliding the meter face back on, check the calibration against a reference if you choose to do so. Apply a fixed 1Khz signal, and bring the LR Master LEDs to 0dB. Your meters should be close, but since this is somewhat arbitrary, they should at least read the same. The calibration pots are on the lower right corner of the VU PCB, but again, if you don't know what you're doing, don't mess with them.

- Slide the cover back on, taking it slowly were the meter plugs run across the meter shields. Reinstall the right bracket, making sure the self-tapping screws go into the correct slots in the housing. Repair/ reinstall the pivot assemblies, and don't forget to reinstall the gray Source Select button.

Congrats! You just rebuilt your VU meters better than new. If you have any questions, ask or PM me.

Pat

P.S. Thanks to Kevin from Mackie Technical Support. He pointed me to JLM Audio.


Edited by Dream Sequence (02/23/13 08:26 PM)
Edit Reason: JLM now has white LED kits