Starting New MB-6582 Build - Any Requests?

[fussylizard]

Hi all,

  I'm starting to build a MB-6582.  First I would like to thank TK, Wilba, SmashTV and the rest of the MIDIBox community for putting together such a fantastic project.  I'm super excited and can't wait to get going.

  I've spent ages reading up on everything and think I have a decent handle on everything.  I've ordered everything except the front panels so far, and am just waiting on the various orders to arrive (SmashTV, CrystalFontz, Mouser, McMaster-Carr, knobs from Goblinz's bulk order, SIDs from Wilba's mega-sale #9).

  The documentation is pretty good overall (thanks again!), though some digging and thought is still required to get everything pulled together.  Pretty much every question/issue I thought of was addressed somewhere.

  I've seen a number of MB-6582 build threads already, so I figured I'd ask if there was anything in particular that could use some additional documentation as I go along.  Once I have verified I ordered the correct part #s I can supply Mouser part #s that can be added to Wilba's excellent lists so far, and of course I can take some photos of things as I go along to enhance the build instructions.

  If there are any special requests for documentation of my build, let me know and I'll see what I can do!

Thanks,

Chris

[Wilba]

Some things that need adding:

Wiring diagram of feedback pots

Uploading walkthrough - people should upload MIOS to each PIC in the Core it belongs to (to prove MIDI In/Out works) then upload testtone app and test audio buffers (i.e. no SIDs installed, bridging pins of IC sockets) then install SIDs and test audio out of SIDs. Some people are too impatient and plug in SIDs before they've got everything else running. It's probably a good idea to get the LCD connected before you start uploading, as another proof of things working.

LCD wiring diagram/instructions could be added, with specific advice about soldering wires to bottom side of LCD only (i.e. keeping pads flat on top side since it touches the control surface PCB).

[fussylizard]

Good suggestions, thanks.  My Mouser and CrystalFontz orders have arrived, so once I have my boards from SmashTV I can get started.  Also I'll be out of town for work next week so it will be a bit before I get started.

If you think of anything else please let me know and I'll see what I can do.

Thx,

C

[Morten]

I just recently started ordering components for a MB-6582. So i will properly also be able to take a look at these things :)

Can´t wait to get started.

[Flemming]

I just recently started ordering components for a MB-6582. So i will properly also be able to take a look at these things :)

Can´t wait to get started.

Ooh, another danish MB6582 builder :) welcome Morten... We can maybe help eachother out if we get stuck ;)

[Morten]

Ooh, another danish MB6582 builder :) welcome Morten... We can maybe help eachother out if we get stuck ;)

Sure sure, if you still need parts then send me a pm, since i might need the same parts. Allways nice to split the shipping costs ;)

[fussylizard]

Quick update: I got my SmashTV order (impeccable as always) on Wednesday so I can get started.  I'm still awaiting my front panels (FPE), SIDs, and knobs, but I have everything else and will start on my baseboard this weekend.  I'm also keeping a list of my questions as I go that may be useful for others later.

One thing I'm amazed about is all the information that is there.  I've been reading over the info, and pretty much every question I've had was answered somewhere.  So advice for those starting out: read everything, and read it several times.  It's a lot to take in at once so the first time or two I read things I skimmed over some details, but later when I re-read things my questions were answered. :-)

Morten & Flemming, good luck!

[nebula]

Things that got me:

If you don't already have some decent clamps, spend a few bucks and go buy a few.  Using crappy, ill-fitting clamps to secure the board to the panel during the JB-Weld process is more trouble than it's worth.

I don't know if it's documented yet or not, but there's an electrolytic capacitor on the lower part of the base board that you might want to put on its side instead of straight up.  If you look at pics of most completed base boards, you'll see what I mean.  If you don't do this, it might get in the way when you try to put the case together.

There are very important instructions in the construction guide to trim away a bit of the plastic on the top-right screwhole of the PT-10 ... make sure you pay attention to this (unlike me), or you will keep swearing (like me) as you try to put the front panel board into place and you end up bending the "SID R" LED.

When buying tactile switches, you will have a choice of how much resistance they have.  This is expressed in "grams of force" or gf.  The standard choices are 100, 160, and 250 gf.  I used 160 gf buttons, and they're good, but I think I would have preferred 100.  My buttons are a little clickier than I would like them to be.  But that's just me being fussy - I still am really happy with the final product.  And if I get ambitious I could always swap 'em out, I suppose.

I had a little piece of tinted anti-glare coating that I glued just inside the display window.  It adds a nice finishing touch.

MB-6582 is an great sounding, very usable synth.  Its firmware is remarkably deep for a DIY synth, and it's truly fun to build.  Take your time and do a good job, because the boards really are beautiful.  If I didn't have a wife to answer to, I'd probably be building a second one!

[fussylizard]

Things that got me:

If you don't already have some decent clamps, spend a few bucks and go buy a few.  Using crappy, ill-fitting clamps to secure the board to the panel during the JB-Weld process is more trouble than it's worth.

I don't know if it's documented yet or not, but there's an electrolytic capacitor on the lower part of the base board that you might want to put on its side instead of straight up.  If you look at pics of most completed base boards, you'll see what I mean.  If you don't do this, it might get in the way when you try to put the case together.

There are very important instructions in the construction guide to trim away a bit of the plastic on the top-right screwhole of the PT-10 ... make sure you pay attention to this (unlike me), or you will keep swearing (like me) as you try to put the front panel board into place and you end up bending the "SID R" LED.

When buying tactile switches, you will have a choice of how much resistance they have.  This is expressed in "grams of force" or gf.  The standard choices are 100, 160, and 250 gf.  I used 160 gf buttons, and they're good, but I think I would have preferred 100.  My buttons are a little clickier than I would like them to be.  But that's just me being fussy - I still am really happy with the final product.  And if I get ambitious I could always

I had a little piece of tinted anti-glare coating that I glued just inside the display window.  It adds a nice finishing touch.

MB-6582 is an great sounding, very usable synth.  Its firmware is remarkably deep for a DIY synth, and it's truly fun to build.  Take your time and do a good job, because the boards really are beautiful.  If I didn't have a wife to answer to, I'd probably be building a second one!

Wow, thanks for the tips, all good stuff!  I hadn't noticed that cap on its side, so thanks for keeping me from messing that one up!

I ordered the ALPS switched recommended by Wilba which are 100 gf, so good there.

As for the clamping, can't you just set some heavy books on the whole setup and avoid clamps altogether?

I'm really excited about the synth.  It will also be great for taking with me on work trips since it is small and self-contained.

Thanks again for the tips.  If you think of anything else please pass them along!

Regards,

C

[Morten]

Fussylizard : It dosn´t have anything to do with good luck, only good soldering  8) No really thanks and right back at you.

Nebula - Very nice tips. I allmost can´t believe how great this community is. I have build a lot of stuff but none have been documented so tight as this.

I like it in here  ;)

Morten

[Wilba]

As for the clamping, can't you just set some heavy books on the whole setup and avoid clamps altogether?

Absolutely not. :)

In the first gluing phase (the corner screws), you need PCB and panel attached via clamps with just a little bit of slack so you can align the PCB perfectly to the panel holes using the shafts of some (unsoldered!) switches as a guide. I can't even imagine how that would be possible without clamps.

In the second gluing phase (the threaded spacers), it's important to clamp at points where the PCB is warped and is holding the spacer away from the panel. That might be at a few points in the middle or on the edge. Again, I can't see how that's possible without a clamp.

I don't know about other countries, but here you can buy a pack of 6 or 8 various sized small C-clamps (from China of course) for $10. They don't need to be that good, you're not applying lots of lateral force, so if it's equivalent to a good firm grip with your hands, that's enough for this job. Four clamps is a bare minimum I think, but I suppose you could do it with two big ones and some other kinds of clamps, ones like clothes pegs or bulldog clips, etc.

[fussylizard]

In the first gluing phase (the corner screws), you need PCB and panel attached via clamps with just a little bit of slack so you can align the PCB perfectly to the panel holes using the shafts of some (unsoldered!) switches as a guide. I can't even imagine how that would be possible without clamps.

Makes sense.

In the second gluing phase (the threaded spacers), it's important to clamp at points where the PCB is warped and is holding the spacer away from the panel. That might be at a few points in the middle or on the edge. Again, I can't see how that's possible without a clamp.

I can sort of see this.  Once I have my front panel and all that JB Weld down it will probably make *much* more sense! :-)

I don't know about other countries, but here you can buy a pack of 6 or 8 various sized small C-clamps (from China of course) for $10. They don't need to be that good, you're not applying lots of lateral force, so if it's equivalent to a good firm grip with your hands, that's enough for this job. Four clamps is a bare minimum I think, but I suppose you could do it with two big ones and some other kinds of clamps, ones like clothes pegs or bulldog clips, etc.

Yeah, same here in the US.  I have a bunch of clamps already but since they are pretty big I'll probably get some small decent ones (per Nebula's recommendation).

My watchword for this project is "fun" (as opposed to say "super cheap"), so a few $ for clamps is worth it to take away frustration!

@Morten - I'm going to grab some lunch and then start soldering!  I'm glad the recommended order starts with resistors since they are hard to destroy. :-)  My soldering skills are a bit rusty, but by the time I get all those resistors down I'm sure I'll be a pro! :-)

[fussylizard]

Update: I've been soldering the base board for about 6 hours.  Resistors in, diodes in, in-socket caps in, sockets in.  I'm about to cut up the headers right after dinner.  Everything is going pretty smoothly.  I'm checking each joint with a 10x loupe (from curiousinventor.com; they have a great "how to solder" video that improved my technique a lot).  I've only had to fix a handful of joints, which is good.

More to come...

[Wilba]

Yeah, same here in the US.  I have a bunch of clamps already but since they are pretty big I'll probably get some small decent ones (per Nebula's recommendation).

Big is good, the bigger "throat" means you can clamp further in from the edge.

I use a mix of big and small.

[fussylizard]

Big is good, the bigger "throat" means you can clamp further in from the edge.

I use a mix of big and small.

Well I have a bunch of large-ish cheap clamps, so I should be good.  Thanks for the info.

Question: The Base PCB has lots of holes with nothing in them.  I'm assuming these are just vias?  I have a few instances in which I accidentally soldered these holes shut.  There is no short with anything and no part is labeled to go there.  Is this a problem?  I got solder out of most of them (solder sucker and/or braid), but I had a couple that I couldn't easily fix, so I left them for now...

I'm calling it a night.  I've soldered from 2 p.m. to midnight with a few breaks, so maybe 8 hours total.  I have the stuff I mentioned earlier done, plus all headers, jacks, base section caps, and the power switch.  Next step is to build out the PSU and test it, then move on to the core and SID sections.

Buenas noches...

[fussylizard]

Update: I got the PSU section built out and tested.  I inadvertently swapped V2 and V3 (I'm using PSU option B), so I had to fix that.  Getting those regulators out was a huge pain since the leads are large and require lots of solder.  The solder sucker and solder braid were not working, but I finally used some Chip Quik and that did the trick (I bought some for my MidiBox CV in case I mess up soldering the surface-mount DAC).  Fortunately I caught it while doing the recommended voltage checks, so no harm no foul.

I also bought heat sinks for the regulators that didn't quite fit.  I knew board space was tight so I got heat sinks that only stuck back .25" behind the regulators, but that was still enough that V1 and V3 were touching.  I ended up grinding off the left-side "fin" for V1 and now everything fits with a little extra space to prevent shorts.  I'll post a pic once I'm further along.

Anyway, I'm ready to test out the first core, but I have some other work to do so it will have to wait. :-(