MB-6582 troubleshooting

[Pyotr]

So I went for the MB-6582 rather than the modular approach.

The base PCB is now done, so I thought I'd run it through some tests. On first powerup, V3 got very very hot.

I was getting 5V at J4, but 9V only read about 8.73V and the 12V pin gave me 0-1V! :hmm:

C2 read as expected, as did J25.

So naturally I disconnected it, doublechecked the PSU B requirements, checked for solder bridges, doublechecked the jumpers...

Everything seemed fine, and V3 no longer gets hot. So, being the ever optimistic (and impatient) newb, I proceeded to upload the firmware [setup_mb6582.hex]. MIOS Studio could not connect to the core, yet it recieved an upload request, so I decided to let it do its thing, thinking perhaps it'd be able to connect once it was done.

Uploading took absolute ages, more than an hour! And once it was done, it still couldn't connect to the core...!

Uploading the testtone app succeeded as well, but no sound was generated.

Tried the ASID player and one of my favorite sid-files; no dice.

So... Have I fried something? Are my CORE and my SIDS (2x6581) still ok?

Perhaps I have a problem with the audio outputs? Or the MIDI ports?

Well... I'm off to bed - this is doing my head in. I'll do some more voltage tests when I wake up, maybe that's where the fault (or one of them) lies, but I'm still very puzzled that MIOS Studio can upload to a core it can't connect to, and that there's no sound other than background noise.

Please dumb down your response to just above retard-level. Thank you in advance.

[Wilba]

First, make sure you are not using a heatsink that is connected between the voltage regulators, as this will not work for PSU Option B (the voltage regulators have different "grounds").

Uploading should take less than a minute. Something is wrong here, so you should remove the SIDs and solve the uploading problem, as well as the voltage problem.

Even if uploading did work, you say the 12V supply is not correct, so 6581s will not be making any sound anyway, even assuming you have set the jumpers so they were connected to the 12V supply (another possible point of failure). You cannot expect to get anything audio-related working until you resolve issues with voltages, check the PIC is working, check MIDI In/Out is working correctly (J11 jumper set correctly, for example), get uploads to take only a minute, with "use feedback from core" checked (if it's the old MIOS Studio).

[Pyotr]

Right, I've removed the SIDs and done some more testing by following the instructions in the base PCB construction guide.

- I get about 5.23V between 5V and ground at J3.

- At J25, I get about 12.4V which seems a little high.

- Measuring across C12, I get about 5V, not 9 as expected. At V1, I get 16V from the left and right pins, and 12V from middle and right pin - so I guess that at least checks out, though it looks a little battered from the extreme heat from the first power on, which still remains a mystery.

- Both the 9V and 12V pins of J1_SID1 and J2_SID1 failed. I get 0V from both and ofcourse 0V from pin 28 of the SID socket relative to ground.

What you said about heat sinks doesn't compute... I soldered the right components at V1, V2 and V3 and they aren't in backwards or anything. So I'm not sure what you mean. What specifically should I test for?

Pins 1 and 2 of J71, J72 and J73 have all been connected by jumpers, and B1, C1, C2, C3, C4, C11 and C12 have all been soldered and C1 and C2 face the right way.

The PSU itself is from my own C64, which works perfectly so I think that can safely be ruled out.