Wilba

People can email me to get on a waiting list.

Thread moved to Fleamarket. The sale of one-off MIDIbox projects via the MIDIbox forum is not commercial intent, and will always be approved.

Good news! I recommend the 10.5V setting. Unregulated power supplies have a max current rating, so that in your case, it will deliver 12V when the current draw is approximately 800mA. When the current draw is less, the voltage will be higher. That's why you're seeing 18V because the total current draw is less than 800mA (probably more like 350mA max). So in your case, switching it down to a 10.5V supply is a good idea... it might even have a 9V setting that outputs 11V... as long as the 7809 gets 10.5V or so, it can output 9V. The tricky part will be that its hard to measure what that 7809 input voltage is when the CS/LCD is connected, and you're drawing an extra 100mA... maybe just once you can take it out of the case, assemble it without the case bottom, and measure voltages on the bottom while it fully working.

The short answer is, I had room to stick the pads for a 7805 "just in case" but I have no idea if that would work, esp. since the current draw on the 5V supply is huge (800mA just for 8 SIDs, 100-250mA for LCD, etc). If you have room, it is probably better to build a separate PSU to deliver what you need for the SIDs you have... ie. 9V and/or 12V for SIDs, 5V for everything else. Or alternately, pass 9V AC to the base PCB and regulated 5V DC that's NOT generated from the same 9V AC supply (but could be from the same transformer) and connect to J1A. i.e. build your own C64 PSU brick.

Now, but not then... It took years of being crazy and being called an epic superdouche before I claimed MIDIbox Hero status.

I bought one from Queensland (it's like the Florida of Australia lol) for $10 or so... looked reasonably clean on the outside, opened it up and it was FULL of some kind of foamy stuff that some insect used to make its home, not to mention insect poop. Filthy, disgusting mess. Still, I was able to salvage an 8580 SID, which worked perfectly.

It was for me! :thumbsup:

... and buy nILS a beer :thumbsup:

Your soldering isn't all that bad... just the pads connected to ground plane... they're the ones that don't have a track connected nor a dark ring around them. Heat dissipates from the joint much quicker than other pads, so they need more heat (and/or better technique) to get the "tenting" to happen. If you have a temperature controlled iron, crank up the temp to 400 deg. just for those pads. Alternately, start with a small blob of solder on the tip, and approach the joint at a lower angle, so you're making more contact with the pad. Send back the bad CS PCB, I am curious to find where it is shorting.

Using the voltage tests section of the guide, test continuity between points that have the same coloured dot. Then with power on, test voltages at those points, and report back any that aren't what you expect. Points marked 12V may not be exactly 12V depending on power supply. 9V and 5V should be very close (+/- 5%)

OK this is getting strange. I'm not following what you say about the continuity tests, but it suggests something like a pin connected to ground isn't well connected, or some other soldering error. Do these tests and report back. Test continuity between "GND" pin on J2 and other ground points (middle pin of 7809 and 7805) Test continuity between "+9V" pin of J20 and other 9V points (JP, 7809, anode of D4) Test continuity between "+5V" pin on J2 and other 5V points, just for completeness. Check D4 and D5 diodes are oriented correctly. If the 7809 and 7805 middle pins aren't connected to ground properly, that will cause problems. Continuity test (or test resistance) between those pins and a known good unsoldered ground point like J2 IF that passes, then while powered on: test voltages between J2 GND and the orange dots, check they're all the same voltage, report them. test voltages between 7809 middle pin and the orange dots, check they're all the same voltage, report them. test voltages between J2 GND and the four blue dots, check they're all the same voltage, report them. test voltages between 7809 middle pin and the four blue dots, check they're all the same voltage, report them. then test voltage at the two other points between the 7809 and the 7805... i.e. cathode end of D4 (where stripe is), cathode end of D5 (where stripe is). Take a photo of the right side of the PCB (top and bottom)... probably won't do much but you never know... I might see something.

not really... You could have a short between the 9V points and ground. What's the resistance between the 9V points and ground?

well that is the problem then... 0.15V into a 5V regulator isn't going to output 5V. If you're measuring 9V elsewhere then there's something wrong between the 7809 and the 7805... i.e. through those two fat diodes.

Not at all... I meant I persuaded nILS to use cheap parts to make any future kit cheaper and easier to stock, i.e. E-Switch tactile switches, C&K black switch cap, standard 8x2 character LCD... I didn't like the idea of using an EA DOG LCD, at $15 they're a bit overpriced relative to the target kit price ($150-$175), I can get the standard ones for <$5, and also not be locked into just one model/supplier.

If you consider cheap parts and looking cool are "features", then I concur. :thumbsup: Oh wait... was it originally a single PCB and I persuaded you to make it sammich style? That sounds like something I would do.

BTW I like the case design too... esp. the nut in the PCB, I'd like to see how that turns out (and then steal the idea) :thumbsup: I've thought about whether it's possible to solder a metal threaded spacer horizontally to a large pad on the PCB (i.e. ground plane without solder mask)... maybe it's also possible to hold a nut in place with a few solder joints.

Nice work, Sasha... I like the changes :thumbsup: If you want to use the "C64" rocker switch (like MB-6582, sammich*, kaffeSEQ), I just ordered 500 and have plenty to spare for any PCB/kit bulk order. By dropping the gap to 10mm, you now need to worry about clearance for the power socket and switch... when I suggested it, I was expecting you to increase the height of both boards to compensate for the cutouts required. On kaffeSEQ, the dimenions are so tight, you need to cut off the outer pair of leads from the switch so it clears the top PCB and encoder. BTW kaffeSEQ is mostly nILS' design, please direct all design criticisms to him :poke: I just do all the boring stuff... :wacko:

You're getting 18V because there's no load. It should drop to 10.5V-12V under load... but since you're using an 800mA adapter it will be higher. I would recommend switching to the regulated 12V DC one and putting shunts in JBP until you sort out the other problems, then you should be getting exactly 12V at points marked 12V. 9V off the left 7809 pin is good... that's the output. What is the voltage going into the 7805? (left pin relative to middle). How are you setting the LCD backlight? (JBL, JR4, position of brightness pot).