Gastric's MegaDrum build

[gastric]

I've started my MegaDrum adventure by placing an order from Mouser.com to build a 1U rack mount version of Synthex's V2.5 board. Total cost of the order is $128.03 plus shipping. That includes a plastic 1U rack enclosure, a few extra copper clad boards, some extra front panel buttons (chose a few different styles to see what I like visually), and some DB9/25 ends to cannibalize to create the programming cables as for some reason I don't have any.

I'll be using this thread to post all of my photos, questions, tips and tricks, and tid bits I learn along the way. My eventual goal is to produce some sort of fairly easy to use documentation to help other newbies reduce their fear and construct their own MegaDrum. Then, assuming I'm successful I can consider taking Dmitri up on the request that someone consolidate all the scraps of how-to-use-MegaDrum info in the forums to create some concise and detailed product documentation. Now that I've written all of this it sounds like a fairly tall order.

Let the games begin!

[dmitri]

Good luck!

[gastric]

Mouser.com order has arrived. Happily, and somewhat suprizingly, they individually package each product in the order and clearly label it. I can't imagine the labor that went into packaging that $0.02 resistor. But for the newbie this makes finding the specific resistor extremely helpful.

Theoretically this is all of the components to create a complete Synthex V2.5 board with the exception of etchant, drill bits, and the BUD rack chassis I chose which is on back order until mid-October. Onto trying to construct a board! I bought a few blanks to account for screw ups and to build the TRS jack boards.

[jman 31]

Very cool! Keep us posted.

[gastric]

Update: After many printing woes I bought a Samsung laser printer, some Staples glossy inkjet photo paper, had more scaling woes with printing (printer seems to scale graphics slightly small probably a driver or internal rasterizer issue in the printer), but finally screwed around with scaling the images slightly in MS Word until they fit the components properly. Toner transfer was easily done on the first try with only a few very minor issues with traces which were corrected with a Sharpie and a razor. And now I have some boards theoretically ready to be etched and cut. I plan to have my wife try the etching and cutting at her work where they supposedly have all of the equipment including a laser cutter. Hopefully that pans out so I don't have to keep 2 gallons of acid around the house.

[gastric]

I got tired of my wife's coworkers delaying my non-company related side project and etched the boards myself. Though the copper looks rough in spots in the photos they're simply surface scratches and I spot checked a variety of the extremely close traces and there's no shorts or breaks evident. Onto cutting and drilling! WOOT! Cutting these boards is messy, Messy, MESSY! I'll actually wear a dust mask and goggles for this part of the job.

Main board, cut to right size for the PCB mounts in the plastic BUD rack case


Jacks boards, needs to be cut


Empty plastic BUD rack case Mouser.com part #563-PRM-14460 I chose this purely due to cost and that it has PCB standoffs/mounts


Main board laid on top of the PCB mounts which are spaced 128mm apart in both directions, and separated by the four large screw posts used to hold the clamshell style case together

[jamdat]

Your build is looking very nice! I hope my PCBs look as good as yours!

Jacks boards, needs to be cut

One question, where did you get the patterns for the input boards? I cannot find them by looking through the threads. This is one component that I actually forgot about!

EDIT: I found them! Skipped right over the thread in the forum.

[gastric]

Here's the link for others: viewtopic.php?f=3&t=178&st=0&sk=t&sd=a

One big advantage of the jacks board is for V2.5 board builders is it provides a mount for the USB jack. Otherwise you have to get creative with your own mount, or buy a $12 chassis mount USB port. Plus, you already have to solder wires to the jacks, why not just solder the jacks to a board? Keeps them all lined up nice and pretty.

Solder most of the components onto the jacks boards last night. Forgot to buy a smaller sized drill bit for the small holes on the main board. The jacks board suffered through slightly too-large drill bits but since everything is spaced so well on that board it wasn't an issue. I just drilled with a Dremel hand tool without issue.

The hardest part thus far has been the soldering. I have a clunky iron with a medium sized tip and it's difficult to heat both the board and component lead without also heating the adjacent lead and bridging them with solder. But I got the hang of it. Tinning the components prior to installation in the board was definitely the key to success with the jacks and IDE connectors. Everything seems secured to the board and after desoldering some solder drip which bridged a board trace everything tests out perfectly via the multimeter.

[jman 31]

One thing that I found that really helps on soldering is to use flux. Even when I use flux core solder, I flux every thing. It helps the solder flow better, and doesn't take as much heat to get a pretty joint. You can also take a file and put a sharper tip on your iron. That will help on the smaller components. And keep the tip nice and clean with a wet sponge.

Let's see some pics!!

[gastric]

Pics of my 10:30pm soldering job. Certainly not professional, but totally functional at least per the multimeter.


Jacks. Generally speaking the jack pins near the edge are sloppy since they aren't completely bound by etched borders, thus the solder runs easily. I'm sure there should be more solder bleed on some of the pins to the actual traces but I don't plan on going back and re-soldering unless something proves to be non-functional.


IDE connectors. These were the hardest to solder due to their size and the extremely close traces.



If there is some extremely critical issues with the soldering speak now. I have less concern about the jacks board since the jacks are physically attached to both the board and the chasis and there's nice large traces to solder to. Which is why I started with the jacks VS the actual main board which is much smaller and intricate.

I saw some external PCB creation sites recommend tinning the entire board which sounds completely reasonable. Certainly tinning everything before the final solder makes the job easier and faster. I'm satisfied at this point to get as far as I have. Considering all of the soldering I've done building two e-drum kits and now the MegaDrum I do whish I'd invested up front in a nicer iron instead of struggling along with my $10 Radio Shack gun-style iron I've had for 10+ years.