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sammichSID short issues


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Hey all!

Pumodi here. I just recently got into MIDI Box building and put together a sammichSID (with 2 SwinSids). Build went pretty smooth but I'm currently stuck trying to upload the MIDI software to the PIC.

I've been going through the MIOS midi troubleshooting tips and have gotten to the point where I did the 6n138 loopback test to no avail. So I'm fairly sure there is a short somewhere in the MIDI I/O portion of the board but am having difficulty identifying it. Any tips y'all might have would be greatly appreciated.

Here's what I know:

It's not the 6n138 optocoupler itself. I've put a few in the socket and nothing changed.

I did everything here (http://www.ucapps.de/howto_debug_midi.html) up to checking the MIDI input section. I've done a few tests beyond that but the loopback tests are giving me pause.

Oddly, if I plug a MIDI cable to a MIDI out port on both the Sammich and my interface the LED's on the bottom of the SwinSid's turn on, even without a power cable plugged in. Is that normal? Also, along that line of questioning, I don't know how to set up the power jumpers for the SwinSids. Do they require power like the 6581 or is it closer to the 8580?

Any help y'all can provide would be extremely appreciated! <3

Edited by pumodi
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The Swinsid has power, so the led is on. Swinsid only needs 5v at the 5v lane and the 9 or 12v lane is not necessary, it just don't cares.

I must ask this because you just write you have problems with the midi upload and I don't know if you just missed something.

Have you followed the flash procedure exactly?

If the pic is ok, than the thing you must do is to check the traces via multimeter-peep and sheet. Or you first resolder a little bit some points which look suspicious. 


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Hey @Noise-Generator, thanks for getting back to me!

Good to know about the SwinSID power, thanks.

I think I followed it correctly. I ended up getting a PicKit 3 and flashing the bootloader onto the PIC. Then I followed the steps on the build guide to get MIOS flashed. Still no luck. MIOS gets uploaded through MIOS Studio right?

I'll try doing the multimeter test and check my solder joints again just to be safe.

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Yes, first you burn the bootloader, than put pic inside sammich, use mios studio, you will get the info that there is nothing connected because you now need to upload mios8_v1_9h and after that you should get the message that your device is connected and than you load up your sammich hex.


Edited by Noise-Generator
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Roger! I followed that procedure and still nothing so I think there's gotta be something else wrong in the circuit. I did realize I had the Voltage Regulators in the opposite places (doh) so I'm gonna swap those out and see how it goes. Hopefully I didn't fry anything.

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