HybrisBehemoth

Starting MB6582 build

96 posts in this topic

will do, sadly don't think I'll get to it until the weekend, but will get to it. 
Was just wondering out loud if there might be a way round it if this turns out to be the issue....

thanks for all the help. Sort of wish I'd just used normal LEDs now, but we'll see!

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Hi.... hope you don't mind me asking @jaytee

now have everything plugged back in. 
have been testing voltage at JD9 and this seems to be 5v regardless of whether the control surface is connected. Is there somewhere else I should be testing the voltage? Also, where would you suggest testing current load? I'm not quite sure where in the circuit to put the multimeter.

With no Control surface connections made at all, everything seems fine. I can plug in up to JD6 working right to left, and nothing seems amiss - LCD still displays correctly, etc.

When I plug in JD7 there is a flickering character on the LCD occasionally... so that's worrying.

When I plug in JD8, this is where the problems really begin. The LCD starts showing distorted text, extra characters etc. The Matrix lights up, but when you select a point on the matrix it seems to leave "trails" of light leading up to the point, or just display random lights.

I am wondering if the transistors here might have been damaged somehow..... I assume they are controlling the LED matrix. I don't really see how that affects the LCD - maybe it is a power issue.

thanks in advance for any advice!

 

 

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it seems to boot up every time fine since I rewired all the CS connections (and got the right resistor values) though....

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well, it now has 2A on the 5v rail and the same issue persists.......hmm, I guess it's worth desoldering the transistors and replacing before I desolder and replace 100 LEDs!

tried the "make all the LEDs light up test from the WIKI. everything lights up fine... no colour changing, but the fast change ones actually look a different colour depending on viewing angles, which is very odd. column 7 is a slightly different colour to the rest.....

can't really work out what is happening here...... I see some desoldering in my future though...

Having read some of the manual I am also not convinced the buttons are all doing what they should in MidiboxSid....

Edited by the_duckchild

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If you’re getting 5V at JD9 then that rail isn’t sagging.

Before measuring current, make sure you know how. Don’t mean to offend if you already know, but it’s very important if you don’t. If you try to measure it like current, you’ll short 5V to ground and likely fry something. (Also, make sure to change your meter *back* to voltage mode before using it again; made that mistake on my TTSH.)

Anyway, I think there’s a header you can measure current from. You would have to break the circuit (take out a jumper) from the 5V regulator and the rest of the 5V rail and insert the meter in series.

If I’m being totally honest, at this point I would admit defeat and install regular LEDs. The fact that your issues start as you plug in parts of the LED matrix and only get worse as you plug in more of the LEDs seems to implicate the LEDs pretty strongly. I’ll be damned if I really understand *why*, but the LEDs do seem to be the factor that differentiates your build from everyone else’s. They’re complex little devices compared to vanilla LEDs.

I haven’t looked very closely at how the LED matrix on the Mb-6582 works, to be totally honest. It certainly can’t hurt to swap out the transistors if you have spares handy, but at this point I don’t particularly suspect them. Sometimes it’s better to try the easier fix before the difficult fix just in case.

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 Thanks... I suspect you are right on the leds.... Still, it was worth a go. Wish I could work out why they don't work! Assume it must be something to do with the matrixing circuit.

I guess if the transistors were damaged I would probably have missing leds when running the test. 

Might just have to bite the bullet and start desoldering...

Thanks again!

 

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Hi Hybris,

I've nothing to add to the thread but was just wondering if your avatar is a block from the game Great Giana Sisters on the c64? ;)

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Absolutely! :) Now i see it, too, thanks, Smithy! I always thought i know this from somewhere but could never "map" it! :)

Hehe, sorry for OT! :)

Many greets,
Peter

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Hi all, have now desoldered 100 colour cycling LEDs and replaced with single colour....... this appears to have solved the issue: no more distortion on the screen, all buttons and encoders now seem to be working fine.

Not sure if it's possible or sensible to add this information to the WIKI... desoldering 100 LEDs was very boring, I'd hate for anyone else to try and be clever ;)

For some reason core 4 is not being recognised at the moment, hopefully an error programming the PIC or a short/missed connection that is easily fixed. It seems I also blew some EPROMs with the reverse voltage from the screen.... otherwise all seems well now. 
Thanks for the advice!

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On 2018-12-17 at 9:01 PM, Smithy said:

Hi Hybris,

I've nothing to add to the thread but was just wondering if your avatar is a block from the game Great Giana Sisters on the c64? ;)

It is indeed. Good catch :)

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everything now seems to be working A-OK.
A number of the "factory" patches I have seem to make no or very little sound as stock.... not sure if that's because they were made for v1/6581s or something?

just changing the oscillator waveform usually springs them into life. The drum kits seem to be good examples of this - although initialising a drum patch seems to work just fine. Pretty sure this is all user error somehow, so am looking forward to learning what I'm doing....

anyway, just wanted to thank everyone for all the help offered, this was right on the edge of what I was confident doing and has turned out better than I could have hoped and taught me loads along the way, plus now I have a really amazing sounding synth!

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@the_duckchild

glad to hear that all works!

There is a difference of filter response between 6581 and 8580 and some patches probably were made for the 6581 SIDs.

You could have a look at:

http://ucapps.de/midibox_sid_manual_e.html

In the Ensemble menu under "FILTERs" you can change MIN, MAX, and LOG to fit to your 8580, if i remember right, especially activating "LOG" helped.

Many greets and have fun!
Peter

 

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ah, great thanks!
to begin with I thought I had issues with some of the SIDs, but then initialised patches always sounded ok, so I assumed i'd missed something.

:)

 

 

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Agree with Hawkeye. The different SID types make thinks a little wacky, but after setting up your ensemble it should be good. Changing the LOG flag is the most important, but I also found that adjusting the min and max filter values was a big help. Just go by ear :)

Most of the circuitry in the MB-6582 is digital, so it’s pretty straightforward. If it seems to be working mostly as expected, ie changing patches, responding to input, proper LEDs lighting, then chances are that any hiccups come down to setting options in the software correctly. The synth engine is really complex, so it’s easy to miss something and get unexpected results!

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Congratulations on the finished build duckchild. :)

I haven't had much time for building lately. And of course I found this site https://www.parasitstudio.se/ , and thus another project to add to the pile of unfinished ones. I'm sure that I am the only one on this forum who owns such a pile...

This weekend, however, I got some time for the MB6582 and finished the control surface. I didn't get the buttons to line up perfectly. So attaching the front panel was a real pain. (My girlfriend actually suggested that I open a window so I wouldn't break it if I was to throw the synth out through it.) I really hope that everything works when I have finished. Because I really don't want to do that again with 100+ LEDs to think about as well.

 

IMG_2418.JPG

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Posted (edited)

thanks!

Yours is looking good! nice knobs :)

I had similar issues with the buttons, they are a bit of a pain!
I have to use tweezers to push them into place from the top everytime I put the faceplate on....
The LEDS were a lot less of an issue, as they sit into the holes, and are a bit further back than the buttons. Although as I had to desolder mine, they were a lot less easy the second time round, and a couple are slightly misplaced.... was so happy to have it working I couldn't face going back to fix them. Maybe one day!

Good luck with the rest of it! (looks like it's on the home straight now anyway!)

Had my first proper play with mine the other day, and I heartily recommend finishing it, it's such an awesome synth - so many modulation options and just the hugest sound, feels like just what I was looking for really. 

Edited by the_duckchild

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Doing some work on this today.

I'd like to reverse-polarity-protect the MB6582. I assume that one of the left over 1N4148_T50A https://no.mouser.com/ProductDetail/512-1N4148T50A wouldn't do for this job. What diode would I need? And where would be best to place it? Was thinking about some of the unused (right now bridged) connections for the bridge rectifier B1.

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Thanks for the link! I have ordered some of the recommended 1N5817 Schottky diodes. Now I just have to wait for the Chinese mailing service...

I could get my hands on some 1N5819 Schottky diodes right now. Forward voltage is a bit higher than 1N5817:

https://www.diodes.com/assets/Datasheets/ds23001.pdf

Any opinions about using 1N5819 instead for reverse polarity protection on PSU option E, only 9v SIDs, 12V wallwart?

 

After looking at the PCBs it seems to me that placing the diode like drawn in the picture would do it. Correct?   

IMG_2435.JPG

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I suspect perhaps @jaytee is your man here as he put together a whole thread on that power supply variant.... (i'm not sure without trying to trace the power...)

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Unfortunately I know next to nothing about best practices when it comes to polarity protection. My own MB-6582 is polarity protected solely by virtue of its oddball 7-pin DIN connector.

That said, I think either 5819 or 5817 *should* work in the given position. 5819 has a slightly higher voltage drop, but I don’t think it’s enough to stop the Vreg from working.

You may also want to look over the power circuit and BOM in the sammichSID. No schematics available unfortunately, but it’s not a big or complicated circuit and there’s a good image available of the board traces, so hopefully not too hard to trace. The sammichSID, IIRC, keeps the bridge rectifier in place even though it’s not necessary for rectifying a C64 psu. This is handy because not only will it protect against reversed polarity, it’ll function normally no matter what polarity supply gets used. I’m not sure what bridge rectifier is used, but it apparently has a small enough drop that the synth functions fine on 12V.

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