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Yet another 6582 troubleshooting post...


MB6582builder
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Hey everyone, after a few years of slowly buying parts and assembling, I'm now at that part of the MB-6582 build where I begin to rip any of the remaining hair out of my head. For whatever reason, the unit powers on to random LED flickering, the LCD flashes, and then...nothing. For as much as I want to blame inanimate objects for this behavior, deep down, I know I have no one to blame but myself. I'm at a loss, and I'm hoping I can bounce a few ideas off of you. I've been troubleshooting this beast for the better part of a month, I've read countless threads, I've reflowed twice, etc. Here's a little info:

- I chose power option B, since I have three brand new c64 power bricks. Not NOS, but NEW new. Everything checks out in this regard.
- I am able to communicate to the MB-6582 through MIOS via a MOTU Ultralite MKIII on Win10.
- I am using a GQ-4x4 programmer to burn the PICs. Everything checks out in the GQ-4x4 software.
- I've built over twenty synths (including an OG sammichSID) and have burned many ICs for other projects. I mention this as a little background.

So yeah, on the hardware side, my multimeter tells me I have 5.11v, 9.02v, and 11.93v on J4. Oddly enough, J25 is telling me I have 19.04v on the 9v-11v pin. I'm not using J25, but it's likely a sign of something astray. I seem to be getting correct voltages on IC pins, but it's possible I missed something specific if anyone had any ideas of where to look specifically.

Regarding the bootloader PIC(s), these seem to burn fine in the GQ software. When I install one into the MB-6582 on slot 1, I get a not found message in MIOS Studio, despite the MIDI loop tests checking out just fine. If I ignore the message, and send the mios8_v1_9h_pic18f4685 hex file, it catches successfully (as far as I understand), and MIOS studio is then able to communicate just fine afterward. At this point, there are no LEDS, and the LCD is still dim. If I then send the setup_mb6582 hex file, this too sends/installs successfully (according to MIOS Studio). I've gone through and assigned the proper IDs to the PICs using the hex files in the change_id_v1_9g folder. Again, everything checks out in MIOS Studio with the device IDs. No errors.

Looking at the device itself, the LCD/LEDs are dim and after a second or two, everything lights up, rapidly dims in weird patterns for a second or two, and then the unit freezes. It's not consistent, and nothing displays on the screen. I've tried the process without the LCD, and I get the same behavior. I'm thinking the boot sequence is *supposed* to be similar to the LED flashing on the sammichSID bootup, but it's nowhere close as-is. The LED test hex file floating around in these forums doesn't seem to do anything in my case.

I'm so close to finishing this thing, but I just need to get it to start! Any ideas?

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  • 2 weeks later...

I had similar symptoms with shorted or corrupted DINX and DOUTS, so I would check in this section. Maybe one IC is broken, maybe has no contact...

My first tip would be reflux/solder but you said, you did that.

Best way is to check every connection via Multimeter and change ICs. Itˋs no problem to put just one hc74* and left the others out to check if they work.

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