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Author Topic: MP-1 wierd midi problem  (Read 833 times)

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rnolan

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MP-1 wierd midi problem
« on: Time Format »

So one of my 2 MP-1s is now working (sort of).  If I power it up and play, it seems to work fine.  All the front buttons work, albeit I have to press them toward the top and much harder than I remember ever having to when I used MP-1 all the time  :dunno: .  When I plug in my MXC it gets weird.  When I change to a different patch the MP-1 doesn't change straight away, seems to wait quite a long time, then change, but not always to the patch selected and the time it takes varies (display seems to flicker).  Turning volume knob to full up or down seems to get it to change (sometimes).  Even stranger is all (well most of) the front buttons stop working while the MXC is plugged in (so can't do any programing) although IIRC I can change midi channel.  If I then unplug the MXC it still stays in this weird state until I cycle the power, then it seems to work normally again (MXC unplugged).  There's nothing wrong with the MXC, it works fine with my MP-2.  Any ideas??
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #1 on: Time Format »

Hey R, I would try to swap the midi boards from one MP-1 to the other and see if that helps, if it does we can do some further fault finding. Seems the problem is there, my first guess would be the uart chip.
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rnolan

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Re: MP-1 wierd midi problem
« Reply #2 on: Time Format »

Hey MJMP, we tried swapping the midi boards, unfortunately that didn't help so we swapped them back.  At that point (while it was still with Tim the Tech) midi didn't seem to be working at all (with either midi boards)  :facepalm: .  Up side was we also swapped the transformers so now the working (ish) unit is 240v.  Also swapped one of the output jacks which was damaged, trying to get at least one unit working properly.  I tested some more when I got them home and I've discovered that at least that one unit works as long as I don't plug the midi switch into it.  So if it is an issue on the midi board, it appears to be on both of them.
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #3 on: Time Format »

So if I understand correctly, you have the same problem on both MP-1's or does the other mp-1 works with the MXC?
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rnolan

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Re: MP-1 wierd midi problem
« Reply #4 on: Time Format »

The other MP-1 (now 117v) doesn't work at all.  When Tim swapped the midi boards (as the working one wasn't responding to midi) it also didn't respond.  When we were doing a quick test at his place, as the swapped in board didn't change anything, he swapped them back.  When I got it home I had a chance to test some more.  That's when I worked out it sort of worked but not really (as described in the first post), and also stopped the front buttons working so couldn't change patch's, edit button kind of worked but up/down buttons wouldn't work.  When I unplug the midi and reboot the unit the front buttons work again,  So connecting the midi seems to put it into some sort of error state.
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #5 on: Time Format »

Can you try something, find a patch with chorus in it, then plug in the midi pedal and listen if the chorus keeps on working? Listen to the modulation, make sure it doesn't do funky bussiness.

Now all the control logic for the midi is on the main board, could be there is something wrong there.
« Last Edit: Time Format by MarshallJMP »
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rnolan

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Re: MP-1 wierd midi problem
« Reply #6 on: Time Format »

OK, turned it on, selected #9 Over Chorused Clean, sounded fine lots of chorus.  Plugged in MXC, MP-1 went to #1 so normal.  Pressed 9 on MXC about 10-15 seconds later MP-1 changed to #9, chorus still fine, no funky business.  Pressed 8 on MXC, MP-1 went to #4 after about 10-15 seconds.  Turned everything off except MP-1, so MXC still plugged in but no power to it.  MP-1 stayed at #4 for a while (while I type this post), I just turned around and checked it, MP-1 now changed to #1 (MXC still plugged in but powered down).  Pressed MP-1 Up button, display flickers between #1 and #2 while the button is pressed then back to 1 when released, if I hold the Up button on for a while, it flickers between #1 and #2 a number of times after I release the button (like command is in a buffer?).  Pressed MP-1 #3 button, display flashes 3 while pressed then back to #1 when button released (but doesn't flicker between #1 and #3 like Up button).  Unplugged MXC and cycle MP-1 power, now front panel buttons work as expected.  Plugged the MXC 7 pin cable back in but no phantom power, MP-1 continues to work properly.  So powering up MXC when connected starts the funny business which doesn't go away until MP-1 rebooted.
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #7 on: Time Format »

Very strange indeed. What happends if you do a midi dump, store bank+6 ? Try it with out the mxc and with.

Maybe a long shot but sometimes it helps when you have strange problems, reset the RAM chip. Either disconnected the battery or pul the RAM (6264 or 5864) chip out.
Now this will erase all your presets.

Can you get your hands on a scope? Maybe we could do a skype session?
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rnolan

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Re: MP-1 wierd midi problem
« Reply #8 on: Time Format »

Hey MJMP, so midi dump displays sending all both with and without MXC.  I pulled the battery (it's in a holder :thumb-up: ) and reset RAM.  Did C 1 to whatever then error 1, 2, 3 and settled.  It's still weird  :facepalm: .  So I press MXC 9 and about 15 secs later it changes.  So all changes from MXC press take quite a long (but similar) time.  But still weird as MXC 7 eventually changes to 3, and MXC 5 goes to 1 (mapping is 1:1 BTW).  So it does change programs eventually but not always to the selected number  :crazy: .  To do a scope/skype session I'd need to do it at Tim the techs, he has a scope.  I'll call him and see what we can arrange.
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #9 on: Time Format »

Did you check if it actually sends something? Do you have a soundcard with midi in/out or one of those usb to midi things?

Some things to try out, reseating the grey cable from the mdi board on both ends. Reseating the uart chip (the 40 pin chip on the midi board), the opto (usually a pc900 or a H11L1, 6 pin) since these are in sockets. Swapping the eprom. Reseating the Z80 and RAM. Probably won't do anything but it doesn't hurt to try anyway. On pin 4 of the opto you have 5V if no midi comes in.

Things Tim could check with his scope, making sure the clock  for the Uart chip is 500.000 kHz (this determins the baud rate), it's on pin 17 and 40 on the uart chip. Also have him take a look at pin 16 of the Z80 if you have interupt pulses there. Let him look at it without the MXC and with and see if there is a difference. Look for the Tick pulses on  pin 4 of U6 (74LS08) on the midi board. Check if the strobe lines to the midi board are working, see schematic of the midi board (TXDT STB,CTL STB,ST STB RX DT STB) these are all active low. So is the interupt. Now in normal circumstances you will see only the ST STB go low, very small pulses going from 5V to 0V, tell him to set the timebase of the scope to 500┬ÁS, you should be able to see them.
« Last Edit: Time Format by MarshallJMP »
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rnolan

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Re: MP-1 wierd midi problem
« Reply #10 on: Time Format »

I can connect to Presonus midi, just a bit a a fiddle with where things are...  I'll have a go at the re-seating chips etc tomorrow.  Still haven't heard back from Tim, hopefully he'll help.
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

MarshallJMP

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Re: MP-1 wierd midi problem
« Reply #11 on: Time Format »

Ok the presonus should work fine, you can use bome send sx, a good and simple software where you can see what the mp-1 is putting out. You can also hook the midi out to the mp-1 and use bome to send midi commands, see how that works out. Since this is all in hex code you need to send (or recieve) 2 bytes, first nibble (4 bits) is "C" which is the code for program change, next nibble is the midi channel (0-F), 0 = midi channel 1, F is 16, next byte is the program change number (00-7F), 00 is program change 1, 7F is 128. Both the midi channel and program change number are off by 1, this is done to make it no so confusing for non digital nerds  >:D

So if you type in C0 00, this means program change, midi channel 1 program number 1. CF 7F program change midi channel 16 program number 128.

Hope this helps.
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