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Starting MB6582 build


HybrisBehemoth
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Working along slowly but surely here. Soon finished with the main board. Passed all the tests without any major setbacks so far. Just managed to get some first sounds out of the SID. :D

The 10 uF electrolytic caps I got were way too big and the film caps are a bit bulky (as you can see). Luckily I had some electrolytics lying around.

 

 

IMG_2362.JPG

IMG_2360.JPG

Edited by HybrisBehemoth
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not for me either actually

p.s. sorry for the thread hijacking, but it seemed easier to keep it in one place while we're both building!

I actually started with the control surface... which I think is probably the "wrong" way round... but seemed easier. 
Just need to get the LEDs in now and will be finished with that board. 
 

 

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also - @HybrisBehemoth - what solution are you going with to power it?

I am pretty sure option E "one PSU" is the right choice, but I can't decide if it makes sense to fool around with a 7 pin DIN and cutting the lead off a 12V PSU..... or maybe laser cutting some kind of acrylic disc for the case so it can just be a normal barrel jack plug and can use a normal PSU.......

 

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Pictures working now?

No worries about using the thread. As you wrote; since we're both building.

I did PSU option E, which seems to be working well so far. All the guides found here has been super useful! I'm planing to use a standard 2.1 jack. The only problem is that my panels have the big 17mm hole for the DIN-jack. Has anybody found a nice solution for this? The disc-solution came to mind for me as well. But I haven't looked in to it further.

I like the multi-coloured-legos kind of look to the knobs! Are you going to do those colour changing LEDs as well?

 

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Pictures looking good now!

I'm going to try the colour change LEDs... and cross my fingers it's not totally stupid once it's finished! Glad the knobs look OK.. they cost a few quid ;)


I was planning on a standard barrel jack too - but I'm wavering a bit now. It feels like either way needs a bit of a bodge, although I guess the barrel jack at least means you can use any spare wall wart, rather than having to solder a new one.

My plan was originally to laser cut an 19mm disc with a 2mm lip and a hole in the centre for a panel mounted jack and glue that into the panel. I in theory at least have access to a laser cutter at my local makerspace... haven't actually cut anything yet though!

Edited by the_duckchild
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thanks, and thank you for the control surface tutorial, really does make it so much easier and answers so many questions!

I was still VERY nervous the JB Weld stage would mess up, was pleasantly surprised when it all seemed to be solidly glued in place!
I think my front panel is very slightly bent though, which is going to make getting all the leds through it in one piece quite interesting. Hoping I may be able to screw the screen in and only have to do it once..... 

Edited by the_duckchild
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I had originally planned on a standard barrel jack for power. I ended up going with the 7-pin DIN for a few reasons.

Probably the main reason is that the header pads for a panel-mounted power jack are close enough to the edge of the board that they kind of interfere with placing a panelmount jack at the same location. You might be able to get around this by placing the jack higher up on the rear panel or elsewhere on the panel altogether, by using angled headers instead of straight, or by simply wiring the jack directly to the board (though this list option will make servicing in the future more difficult).

The above hurdle could have probably been surmounted, but lo and behold, a 7-pin DIN connector randomly fell into my lap. I had been asking around for a source on the OG power switch, and a kind forum member hacked off a piece of original C64 PCB for me that contained both the DIN jack and the switch. Obviously this won’t be the case for y’all, but having the part in hand made the decision a bit tougher.

Other, minor reasons I went with the DIN jack: no need to redesign that part of the panel (I had custom panels made but I didn’t want to change any more than I had to), and no possibility of using the wrong voltage/polarity power adapter ever.

Attaching the new jack to a power adapter was really easy; don’t let that be the only reason you shy away from the DIN connector.

That all said, if the part hadn’t magically appeared for me like that, I’d have probably figured out how to use a barrel jack. I’m afraid I can’t advise on how to adapt the DIN sized hole to a barrel jack though, that’s a tough one. I had planned on custom panels from the beginning.

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Also:

Pictures are working now, looks good! Those filter caps are a little hilariously big, lol.

And I love the rainbow knobs on the other synth! Reminds me of the original C64 marketing logos. I wanted to do something similar, but it’s relegated to just the feedback knobs around back.

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Just looking at the details on programming your own PIC chips... didn't realise I needed to build an adapter board!
Is this still the correct info on doing this? Seems like there's not much other option, so I had just ordered a Pickit 3 and 40 pin programming adaptor off ebay, but I guess the adaptor was a waste of money.... d'oh!


I suppose it's not too much bother to solder a little board to program the chip...

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On 2018-09-22 at 4:11 PM, HybrisBehemoth said:

 

I used this PicKit (which should basically be the same as 3.0) and adapter. Worked fine.

Found this video useful:

 

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  • 2 weeks later...

possibly a silly question, but just in case anyone's around.....

Should my LCD power up/show something with no cores in the board?

I sort of expected yes, but it doesn't even though there appear to be the right voltages and i have rechecked all wiring. Does it need a data signal of some kind to turn out? Just about to try burning MIOS in but if my LCD doesn't work I have no means to tell if it works or not as I ordered the wrong audio outs as well and am waiting for replacements!

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unfortunately there's no sign of life from the LCD at all.no backlight at all.

After a bit of messing about in theory have MIOS and the mb6582 software installed on a pic, but still no sign of life from the LCD...

Can I ask - is your screen a Midas? Just looking at your wiring in the pic above and pins 15/16 look reversed compared to mine.... 

also, the pins on the board are labelled "1" and "9", but from what everything suggests I think those pins are 1 & 2? is that correct? if this is the case, pins 2& 3 seem to be shorted by the pcb... not sure that's correct!

 

 

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I think the backlight should turn on even without a PIC. Is everything else on the board populated? (Thinking specifically about the display trimmers.)

The LCD wiring is confusing and was one of my more troublesome spots. I managed to wire it up backwards (or upside down...or something) even after double- and triple-checking my work.

Can you do me a favor and post a picture of your wiring and links to whatever documentation you’re working off of? I’m trying to figure out what you mean with the pin numbering (and the more general issue of it not working, of course).

Edited by jaytee
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oops - sorry, missed your post Jaytee - was working from this:

http://www.midibox.org/users/jim_henry/building_a_midibox_lcd_cable.pdf

which numbers the headers differently to the labels on the board it seems?

Mine looks like this;, brown on the right hand end being "pin 1" and then red as "pin 2" according to that guide, but marked as "pin 9" on the board

 

thanks for any suggestions!

DSC_0512.JPG

Edited by the_duckchild
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thanks - that suggests I've probably blown something or done some dodgy soldering I guess!

If the LCD backlight should work as soon as it has power, will test just those two pins with a separate power supply first and make sure I didn't kill the screen.
Then I guess triple check the screen wiring/contrast pots/transistor

tbh I am pretty sure I have the wiring right at this stage, so maybe I messed up elsewhere...

Edited by the_duckchild
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Found your thread by the way Jaytee
 

sounds like maybe the backlight polarity was reversed? can't tell from that really if it was just the backlight or the whole wiring though....
Stuck at work now, but going to try just powering the backlight both ways when I get home.
Because it's a negative screen it might just look completely blank/dead with the backlight off, maybe it's fine.... I hope anyway <fingers crossed>

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My issue was that the entire cable was connected backwards at the LCD end. I still got some functionality because both sides (pins 1&2 and 15&16) are power (one side for the actual LCD and one side for the backlight) so everything was in fact receiving power, but nothing else was connected correctly. I am pretty sure this isn’t your issue.

Looking over your display’s data sheet (specifically the pinout), it seems like maybe your display needs a negative voltage reference for the backlight to function? This issue is described in the LCD troubleshooting document (http://www.midibox.org/dokuwiki/doku.php?id=troubleshooting_lcd_displays) but unfortunately the solution is not described there: it only gives a dead link. :/

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