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WIGGLING 'LITE' IN GUEST MODE

Power Supply #2 Finally Finished
MUFF WIGGLER Forum Index -> Music Tech DIY  
Author Power Supply #2 Finally Finished
JohnLRice
I would have been done earlier but I screwed up (see this thread https://www.muffwiggler.com/forum/viewtopic.php?t=2577)

I was also going to do step by step photos of the building process and make a web page with instructions but . . . i got in a hurry and just wanted it done so I quit trying to take pictures. I'll post what I have here with some quick notes.




Here is a picture of about 99% of the parts used:






Here it the panel after I finished drilling it. I used the panel from the first power supply as a template to make things easier. At the last minute I decided to so a semi mirror image layout instead of identical because I realized that if they were identical I wouldn't be able to reach the power switch on the second cabinet if I needed to! (the cabinets will be sitting right next to each other and up against a wall) I was for a moment going to make the totally mirror image but i thought that being electrically consistant was more important then being estetically 'cute'! Mr. Green I also needed to mount the panel in the cabinet and set the Power-One chassis in there to remark the chassis to panel mounting holes because there seemed to be some minor spacing differences between the first and second units. The rectangular hole for the power entry module was lovingly cut with a Dremel tool using a reinforced cutoff disk. Makes a sweet shower of sparks! Make sure to keep containers of gun powder and gasoline soaked pets at a distance! BOOM! Flamed!





I decided to mount the MOTM-990 distribution boards on top of the Power-One chassis partially because it seemed like a convienient placement and also because two of the transformer bolts lined up perfectly with the mounting holes in the MOTM-990. (the circuit board holes needed to be drilled one size larger though). There was enough of the transformer bolts exposed so I could just screw the threaded nylon standoffs right to them. I then needed 6 more bolts and nuts. I suppose i could of epoxied the remaining 6 standoffs to the chassis but . . .that would of probably sucked! While removing the two circuit boards was nessesary to drill and mount the standoff bolts that are over the boards, removing the transformer too made marking the holes MUCH easier (I didn't do that on the first power supply! d'oh! ) Also note that the top of the Power-One chassis may not be perfectly flat. My first one wasn't so I needed to loosen a couple of the stand offs so that the distro board wouldn't be flexed/stressed when bolted down.





Note that 4 of the bolt heads are underneath the circuit boards so making sure they have a low enough profile to not touch the underside of the board is critical. I needed to trim the leads as close as possible near the bolts to be safe. (I probably should of insulated the bolts but i think they are OK . . . . look for another "DAMN IT!!!!" post in the future in case I'm wrong! meh )





Here are both finished power supplies. Power supply #1 is on top with the blue distro board and power supply #2 is on the bottom with the green distro board. Word of caution: be really carefully when wiring up these MOTM distro boards because the polarity of the terminal strips is flipped on each end of the board! angry Maybe that was done so the + connections are always on the left hand side when veiwing the board from the edge but . . . having one set of terminals and ALL of the MTA connectors line up one way and then having the other terminal strips line up another way has screwed me up twice so far! very frustrating :





Looking at these I can still think of some stuff I should of done to make them 'better' but . . . they are both quite as a Ghost's fart and work perfect so . . . . I think I'll install them in the cabinets and get back to using my synths again!!! hihi



Feel free to ask question or point out stupid stuff! w00t
Roycie Roller
Very nice! What are the banana jacks for?
JohnLRice
Thanks!

The banana jacks are just the different power supply voltages and are there for several reasons:
    * so I can check to make sure the voltages are OK without taking anything apart
    * with a special adapter cable or two to test new modules or ones under repair without having to mount inside the synth case
    * in an emergency (live performance etc) where one power supply dies it might be possible to jumper the voltage over from the other cabinet's power supply to get through the gig. (untested . . may not work well for a couple reasons)
    * becasue banana jacks look sweet! nanners I probably should of used binding posts for versitility but I thought they wouldn't look as cool! hihi


Below is a detailed image of the bananers with labels added (photoshopped). For the most part I used the same colors as MOTM power wiring (except the blue isn't dark enough and the yellow should be brown! d'oh! )

Roycie Roller
Nice. w00t Are they Johnson banana jacks? Where'd you get them from?
JohnLRice
Roycie Roller wrote:
Nice. w00t Are they Johnson banana jacks? Where'd you get them from?


Yeup! Around $0.60 each from Digikey (figure 17):
http://dkc3.digikey.com/PDF/T091/P0405.pdf
wetterberg
I was going to ask why build what's basically a power output and then build two of those - but I saw the PSU is 0.8a @ +-15v, so it's for the best to have two, for sure.

I plan on doing pretty much the same thing, only with just one power connector at the back and one 3.4a power one per "send / receive pair"
JohnLRice
wetterberg wrote:
I was going to ask why build what's basically a power output and then build two of those - but I saw the PSU is 0.8a @ +-15v, so it's for the best to have two, for sure.

I plan on doing pretty much the same thing, only with just one power connector at the back and one 3.4a power one per "send / receive pair"


yeah lol the problem with planning stuff, at least in my case, is I almost always underestimate how long it will take and/or how much resources I'll need! meh

Originally i was just going to get a 6u high rack and put a sequencer in it to control my MiniMoog but . . . long story short, I finally got up to the point of planning on a single 12U high rack with a 6U high rack on top powered from the main cabinet. Even after I decided to go to two 12U cabinets I was still going to power the second cabinet from the 1st since a lot of the 'planned' modules were wide and the amperage should of been sufficient. I even purchased two different sets of multi-pin connectors to get the power over. (and I think now if I was actually going to power one from another I'd get some more beefier multi-pin connectors than the ones I did get!) So . . . I kept cramming more and more into the first rack until now where everthing together will be needing almost 500ma of power. The second cab's power is a little less but total of the two together was getting withing 50ma or less of the supply rating. Not good so I opted for the second supply.

I decided to go ahead and put the bananers in anyway for the reasons I listed above and I stands by 'em! razz
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