GEAR: Matrix 6 and Matrix 6r

[playthatbeat]

I just spent 4 hours chasing my tail.

I had this issue where Voice 5 and 1 were sounding a a bit dodgy on some patches.

Moving the voice chips did not help, the faults were with the channels themselves, not the CEM chips.

The issue was related to the amount of CV from mod matrix being sent to Filter cutoff. Voice 5 would cut out if i hit the key hard enough! DMM showed different voltages on each Filter CV pin, and dropping the Filter frequency in the edit menu restored the voice to sounding. Some waveforms worked, some did not, some patches had the issue, some did not.

ANYWAY. The solution is to do a boot calibration - hold STORE while booting. Doing a TUNE or CAL while booted DOES NOT FIX THIS - it needs to happen during the boot.

[playthatbeat]

Calibrating the Matrix 6 is no big deal. Get this: http://www.synthzone.com/midi/oberhe...nual-HIREZ.pdf

There are 3 things You need, a DMM (multimeter) that can do DC millivolts, a Frequency counter or preferably oscilloscope that displays frequency as well as waveform (most do now) and a 3mm screwdriver. If You do not yet own an oscilloscope, and You are reading this, it's time You did. Look at a Hantek from Aliexpress. They will not only show waveform shapes, but measure voltages and frequencies, so a useful bit of test gear to have.

Follow the guide in the manual - basically 4 things to do - the DAC, where You twiddle the little pot on the voice board while hoping for as close to 0.000 Millivolts as possible on Pin 6 of U712. Don't fret, you will NEVER see 0.000, try for 0.00? and call it a day. Then the HROs, 3 cores L2, L3 and L1 are gently changed with the tiny screwdriver - again You will never get this bang on, so the manual suggests a range to get within. This is tricky, as the cores are sensative to nearby objects - like a screwdriver. You need to tweak, remove the screwdriver and take a reading. PITA. OH, and the pins you need to monitor for frequency, you count from the top left anti-clockwise to find the correct numbered pin. Just in case You are totally new to this! You need to measure pin 14 of U732, 733 and 736. U736 is obscured by the ribbon connector, but You will find it no bother. You can ground your probe on the lid support metal towards the front of the case for the L1/2/3 bit, the manual asks you to use a - leg of a cap for the DAC bit - connect your - of the DMM to that leg (alligator clip attachment?)...

Each step requires the unit to be in a service 'state', these are accessed in the MASTER MENU #52, by holding combinations of A B C D buttons. Calibrating the unit while NOT in these states is the biggest cause of crap sounding units. My m6 had clearly had it's HROs done in normal mode when i first got into it, making it sound flat in tuning.

[playthatbeat]

Dug out the M6 this week, decided to finally get the STEREOPING unit i have had for a while working with it.

I see the patched Firmware at http://tauntek.com/Matrix6Firmware.htm has had an upgrade to 2.15 since i last looked. I may upgrade.

The m6 has been flakey since i picked it up, so I carried out the following work in an attempt to make it solid:

Replaced the battery with a holder and a removable CR2032, replaced the mains filter/IEC socket (these all contain caps and go bad evenyually), made a new longer ribbon cable to link the 3 boards, re-flowed all the solder on the connectors on the control board.

All the parts for this are available everywhere, but watch out for the power filter, it needs to be a perpendicular one, as there is not enough room to use one with the tabs at the rear. I got my bits at RS:

Schaffner 3A, 250 V ac Male Panel Mount IEC Inlet Filter FN 9226-3/06, Faston None Fuse
Stock no.:302-9896

RS PRO 1.27mm 20 Way Flat Ribbon Cable, Grey Sheath, 25.4 mm Width, 5m Length
Stock no.:289-9896

3M 40-Way IDC Connector Socket for Cable Mount, 2-Row
Stock no.:323-7946

RS PRO CR2032 Battery Holder
Stock no.:185-4782

Panasonic CR2032 Button Battery, 3V, 20mm Diameter
Stock no.:457-4757

Had to get a run of 20 Way ribbon, as they had no 40 way in stock, so used 2 bits side-by side. Copied the orientation of the connectors on the lead originally in there, added length so i can run while the case is open. I also bent all the pins on the sockets for the lead slightly inwards from the edges to make the socket tighter, as You do.

I had to remove the control board to do this of coarse, and i discovered a real PITA - mounting the board back on the lid correctly. You need a powerful light - place it inside the case, loosely mount the board with all screws half-in, and look thru' the membrane from above, using the light to show you how the buttons are aligned in the holes in the case, then tighten one of the centre screws. Check all the buttons are centred in the holes all-round, and tighten more of them. IF YOU DO NOT get the buttons bang on centred, they may be triggered by mistake or full-time, and you will not be able to boot the machine properly as it does strange things during boot depending on which buttons are held down.

During all this i lashed in some new presets using the http://www.midiox.com/ tool's player by just playing the MID files into the m6 - i'll attach them to this post - and went thru' the calibration of the 3 HROs and so on, and my oh my it sounds so nice. OH, i did have to replace a CEM 3396, one of the waves was acting up on voice 6, so as i ate into my spares stash i went looking for more. HOLY FU*K they are expensive now! $40 for one? Suck mah ball$. I'm good.

Anyway, The Stereoping synth controller is great fun (remember to run in QUICK EDIT mode on Your m6 Kids!) and i have decided the m6 is my new old pal, er, again.

No @@@@@@@@@@@@ display or random bullshit since doing all of this work, so i am happy.

Also: WAY back i bypassed the volume slider, and thought i had damaged the machine as it never worked in STEREO mode - only 1 side ever made sound - now it works in SPLIT mode, i can run 2 part multi-timbral, with a voice in each output.. the HEADPHONE socket uses a resistor-based summing circuit to make a MONO sum of the 2 channels, but the individual LINE outs are discrete channels. GO FOR IT - 2 x M6 oh yes, it's real.

[playthatbeat]

My Matrix 6 still has all it's voices intact in 2020 - polar opposite to the M1000, which has NONE of the original 'slim' voice chips now, but the issue with @@@@@@@@@ in the display was happening sometimes, and it's almost certainly down to the ribbon cable connecting the processor board to the control/display. The stock one is too short, and should be replaced with a longer one. It's been easier to obtain these leads recently - they are basically IDE hard-drive leads with ALL pins connected, and no blocked 'keying' holes on the connectors.

[playthatbeat]

The bright Dot in the display thing i remember, but i don't think it's related to how the voices are working, i think it's more about the voice rotation or stacking mode in the patch perhaps? BUT, if one voice is sounding a bit strange, then it is probably an unwell voice chip alright. There are very slight issues on some patches, and others You can clearly hear it is missing every sixth note or whatnot. Watch the display and see which dot is on when the faulty voice fires, and that's Your culprit - swap it with the chip next to it and see if the fault moves with it, and if it does, it's an easy fix - replace the chip! They are still on aliexpress and ebay, no big deal. If it's a TONAL issue on that voice, then i would bet You 5c it's the chip. Remember the dots are read left to right for 1-6 but the physical layout of voices is right to left, er,. i think. Been a while

[jicamasalad]

Well hello again...

And apologies for the radio silence...y'know, "life" conspires to pull me away from the solder smoke and old synths.

So my M6R is booting so very happily, since I rebuilt the PS board, and followed you suggestions, however I am now having an issue similar to one you reported: just ONE of the voices seems to have the filter cutoff wrong more open than the others - if i cycle through six notes on, say, a warm stringish pad, the voice whose "period" indicator is by the first character of the display is brighter than the other five. On some sounds of mine you can't notice (depends on how the filter is used in those patches), but on these dark mellow warm pads it's like a tiny bucket of cold water every few chords!

Where would you suggest I start to troubleshoot this? I was going to begin by swapping chips and seeing if the fault follows to a different voice indicator; beyond that you've mentioned something about calibrating the HFO, but that will all be new territory for me. Could you share any more specific info? Of course I'll also re-seat all the ribbon cables, and give a good Deoxit burst...

Thanks for any help...

Kent

[playthatbeat]

Hah Fantastic, You still have the TANDY cassette deck! I have been using just a soundcard in/out for these things, and it's actually quite twitchy.. must be the full bandwidth of it all..

OK, Fine Fine on the build, i guess the only thing left is those pesky Ribbon connectors, which i suggest You hit with some DEOXIT if You continue to get issues. The downside to this fix is you have to keep doing the Deoxit shuffle every few years, and Deoxit dependency is a common problem - once You start, it tends to fix things right away, but over time causes another buildup of [stuff].

Yes, the M6 is such a classy device, i really could not do without one. the M1000 is all very well, but it does nto sound the same. Take for example the last couple of patches in the factory bank - the crazy looping SFX, they sound totally different on an m1000 to the m6, just a hint at how things changed between designs.

[jicamasalad]

M6R PS Rebuild

Well, I've just checked the voltages on the output side of my completely rebuilt M6R power supply board, and all is well!

Hooray!

I replaced not just the caps but every component, as well as added .1uF caps across the diodes for extra switching filtration. Everything seems to be supplying the correct voltages; next step is to install a battery holder and replace the old battery, then install the new v2.15 firmware from Mr. Grieb and reseat all those ribbon cables and pray for the best.

It turns out I was able to dump all the patches through SYSEX into Protools; my confirmation method was flawed: once I changed the patch, then switched BACK I saw the "restored" patch name. I do still have my old Tandy Data Cassette recorder just in case.

Will post one last time when (fingers crossed) all is back together and humming beautifully. Good gosh how I love this old synth!

Cheers,
Kent

[playthatbeat]

Hi Kent..

The Matrix 6 & 6r had the Audio interface for loading & saving patches, so i never needed to use anything else on them, while the Matrix 1000 did not, and required a librarian to get patches in & out of the first 2 banks (or is it only the 1st bank??).. There were many librarians and editors in the past that support the Matrix 6, You should be able to google up some abandonware, or an old cracked version, long since abandoned. My Librarian is a DOS app as part of Voyetra sequencer+, wich supported everything up to about 1996..

M6 and M6r also have very poor response times for sysex - as discovered by anyone who has tried to edit patches using sysex remote control - packets get lost, the units freeze, and things are very sluggish at best.

I suggest you avoid the Sysex patch dumps, and use a librarian software if You want to do things by MIDI, or use the audio interface (TAPE IN/OUT) to make a recording of the patch dump in audio form, since You have a 6r, and not an m1000.

As for the "@@@@@@@@@@@" crap in the display - good luck fixing that, it should be a simple matter of changing all the capacitors on the power supply board.. Make sure you dab all the solder points for thew caps with some FLUX, and use nice quality solder braid to soak up the old solder, adding some new solder to each first to loosen it up of coarse! Take Your time, there is no hurry, and then enjoy Your nice stable 6r

[jicamasalad]

SYSEx All Patch Dump before PS Rebuild...

Greetings and thanks so much for this info.
I am about to rebuild my power supply for my Matrix 6R, which i purchased NEW in 1986!
I'm having that gobbledygook on the display, but thankfully all voices are working fine...

My question sounds terribly "newbie", and I'm not really a total goofball, I promise, but I'm a little unclear on something:

I am trying to dump all my patches via MIDI SYSEX before I begin these repairs.
I have the M6R hooked up to Protools, and I record a block of data and can see the SYSEX data chunk in PT.
Now I want to verify that that data is good, so I alter a patch name and save it, then wish to reload all the patch data from the SYSEX file in Protools, (to see the name restored as a sign that the data was replaced). I hit play in PT and see MIDI activity heading to the M6R, but it doesn't look like anything happened, i.e. the altered patch name did not revert back to the original name.

I feel as though I'm missing something stupid, but how do I set up the M6R to load all the patch data from the SYSEX bulk dump? The manual only mentions how to SEND this data, not how to load back from such a data dump.

Please advise, and again, apologies for the stupid question.

Cheers,
Kent

[playthatbeat]

Something just had me going round in circles for a while.. A clicking voice, or a trembling voice, or a digitally unstable voice-fault that MOVES depending on where You are playing the keyboard - so, it's not the voice chip itself, it's something more annoying..

Anyway, it was the ribbon connector that chains the boards and the control board - anything up with that, and expect a fault that seems to jump from voice chip to voice chip, and cannot be attributed to any single voice.

Same lead as an UNBLOCKED IDE lead - ie: with no key pin that is blocked..

Hard to find these days, but it's bound to be behind any mad digital/control problems - reseat it, be gentle..

A clue to this problem will be if You are holding the garbled voice ON by pressing a key, and you open and close the lid while doing this, and the fault changes as you move the lid - then it's the ribbon cable, likely with a GND problem, but a severe disruption that will get worse or better as You move the lid..

[playthatbeat]

Service manual, in case You cannot find it, or more to the point, in case I cannot find it

[playthatbeat]

My m6 went batty - lost a voice, so i swapped the voice chips about to see if it was the CEM, and LO! it's happy again..

Uploaded the factory patches, and although they gave an ERR 5 or ERR 2, they did load 100% :/

ALSO: installed that rom (above post) so i ripped my ROM and attached it here - it's for a 27C256 eeprom, and is marked as "M6R 2.13" - so appears to be the firmware for the RACK M6..

[playthatbeat]

New Firmware..

A smart cookie, Bob Grieb, has been doing some poking about with the firmware of the M6/M6r, to improve it's habitual clogging, read about it and get a copy here: http://tauntek.com/Matrix6Firmware.htm Have not burned his code to an eprom yet, but i will next time i get a hankering for some m6 action.

He has also released modded firmware for the matrix 1000 here: http://tauntek.com/Matrix1000Firmware.htm

and has an interesting observation for those of You with MAD VOICE syndrome: http://tauntek.com/OBMatrixSix.htm

Great stuff

[playthatbeat]

Here is a rip of the original Matrix 6 audio cassette from oberheim, dated 3/6/1986 entitled: FACTORY STOCK PATCHES/VOLUME2 in .wav form..

You can use this to restore patches to Your machine when the battery dies and you couldn't be arsed looking for a sysex dump to get it normal again..

Sometimes the machine corrupts it's own face for other reasons - some patches behave strangely, and You think maybe the hardware is about to fail bigtime - this can maybe be just plain old brainrot - try backing up Your patches first, then get these in and see how it sounds..