I have been using seq v4 since a year without problems.
Suddenly today this error message pops up saying “MIDIProtocol Timed Out!!!”
In addition to that, on midi I/O board, OUTB Led is constantly lit, while it’s not configured to do anything. No problems on OUTA however.
Midi in is not working, seq v4 does not receive any midi clock unless it’s from usb.
When I monitor OUTB, it is transmitting a C-1 note off message very rapidly, perhaps choking the system.
I am using my desktop computer for powering and never had problems before.
Just now, I tried an adapter that I use for my phone, capable of 1A, nothing changed.
I measured Vd’s around and it is 4.85~. Power is making through Midi i/o and cs board, no problems there.
Just now my CS board failed aswell, it’s making nonsense. I changed BC377 and all the other IC’s with brand new. No help.
Edit: Just now the LCD’s decided to come back, but the CS is very wrong things, it’s like buttons are misplaced.
Are the LCDs powered by 3V or 5V? How hot is it where you are? Without much more info, the problem could come down to the DISCO board voltage regulator overheating. Is the USB cable okay? Maybe the connection doesn’t make good contact somehow.
Good call, Andy, +1 for the tiny disco 3v regulator or the usb cable being the problem, had both problems before!
Missing/misplaced buttons might be due to problems to access the SD card and being unable to load the configuration file, that would be another argument for a 3V regulation problem. Can you measure the stability of the 3V rail (there are top pins on the disco headers, that can be easily reached with a scope/multimeter)?
But it might also all happen due to a soldering joint going bad on the core, you could visually check and reflow/resolder all of them.
LCD’s are 5v mode and the weather is pretty hot, around 35C and even my modular gear is starting to act weird.
I could only measure the rails with my cheap multimeter and there isn’t fluctuation.
So I became really suspicious and reflowed everyhing and then alcohol bathed for perfection aaand things started to come back! CS is back and the midi i/o is working again.
Only problem now is that LCD’s initialize well, but glitch in a couple of minutes and the communication is completely lost and I have to reset the device.
On idle mode, nothing playing, cpu shows %80. Is that normal?
I’ll keep debugging power related issues. Thanks a bunch!
Cool to hear, that reflowing helped! Glitching LCDs could also be because a lot of things, this comes to mind:
a) too long display cables picking up noise, you could press on a ferrite core on the display end of the cable, it helped in some cases for VFDs in the forums.
b) “unclean” 5v, especially from switching PSUs somewhere. Sometimes a stabilizing cap directly at the lcd +5v/ground pins helps (something like 100uF) - it did for my OLEDs.
If you do suspect the 5V supply being noisy, you could create a “clean” (nonswitching) PSU using a heatsinked 7805 circuit (schems all over the web), that directly outputs into a micro USB plug (only connect the red and black wires after stripping the usb cable), test polarity first with a cheap usb device before plugging into the core! The 7805 could be supplied with a cheap 9V/1A (or so) wallwart. This would ensure a hot heatsink, but really clean 5V power. It is great to have such a supply as a tester for such problems, especially when components like displays freak out after a while, in my experience a lot of these problems are power supply related.
I have 7805’s laying around, I will build the circuit
So you are basicly saying “use a linear supply”. Something like a AC-AC wallwart adapter stepped down to around 9 volts, then rectified into dc and regulated by 7805 right?
Then I’ll have to modify a usb cable so that it receives power from the psu, and transmission from pc. Well well, lots of work to do
So you are basicly saying “use a linear supply”. Something like a AC-AC wallwart adapter stepped down to around 9 volts, then rectified into dc and regulated by 7805 right?
I’d just recommend to test with a PSU with known behaviour, a linear comes to mind - in the end it would make sense to run the SEQ off a switching PSU, because it is far more power efficient. I’d just recommend to have a linear PSU ready for testing this stuff - because if you have one and the displays still show garbage after a while, you can be quite sure, it is not power related (ripples, noise, radio interference from the switching circuit). It should be possible to build one within reasonable time, too, it is just a few big input caps, the 7805 (if you are buying it new, buy a 78S05 with a huge heatsink), two caps close to the regulator and maybe an output cap and that’s it :-). You can re-use the PSU for later projects.
I’d just recommend to test with a PSU with known behaviour, a linear comes to mind - in the end it would make sense to run the SEQ off a switching PSU, because it is far more power efficient. I’d just recommend to have a linear PSU ready for testing this stuff - because if you have one and the displays still show garbage after a while, you can be quite sure, it is not power related (ripples, noise, radio interference from the switching circuit). It should be possible to build one within reasonable time, too, it is just a few big input caps, the 7805 (if you are buying it new, buy a 78S05 with a huge heatsink), two caps close to the regulator and maybe an output cap and that’s it :-). You can re-use the PSU for later projects.
Oh I see your point now! No need to build anything then, I already have a bench style supply
