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Re: only one board active
Hi Terje,
It is a long shot, but try reflowing the solder on the socket of the DAC. Ya might get lucky.? Best Karl ________________________________ From: Terje Winther <terje.winther@...> To: xpantastic@... Sent: Thu, July 12, 2012 10:59:39 AM Subject: Re: [xpantastic] only one board active ? Hi all, Thank you very much for all the feedback and the hints of what to do. After a day?s break from the Matrix-12, I once again got into it with renewed energy. I *might* have found the error, but I am not sure. To recapture: Today a took both voice cards and swapped positions of the "board ID" tag (strap). Earlier there was always voice 7 - 12 who failed, and after the swap, voice 1-6 failed. So there is no doubt now: There is an error on the voice card. I swapped the straps back to the original positions, and inserted the cards and tried a few other options: - I tried new 4051 ICs at UX06 and UX07 on one of the voices. No change. - I tried new TL084 at UX08 at one of the voices. No change. - U108 (LM311) have been swapped. No change. - I have swapped all critical ICs U812 to U815 with the working voice card. No change. - I have swapped the processor U907 and the timer IC U921 with the working voice card. No change. Voice card two (the upper card) fails on all 6 voices as regard to VCOs, VCFs and VCAs. It comes close, but not perfect (off by as much as 0,5 - 3 notes). On the other hand, this is what is working: - There is sound from all 12 voices (if I override the automatic tuning and turn all voices manually on) - All 12 voices responds to keyboard, levers and such - All 12 voices change sound according to the stored programs, and changes done on the front panel - All voices pass tuning of PW (Pulse Width) and RES (filter resonance) So I started backtracking to other ICs, and I might have found the error: U811, the 3140 DAC chip. If I swap this between the voice card with tuning error and the working voice card, the tuning error follow the chip. Kind of strange, since all other activities also goes through that chip, and all other activities work as they should. Moving ICs before and after U811 changes nothing, but moving the 3140 DAC makes the tuning error move as well. So I am tempted to borrow a 3140 chip from the other Matrix-12 to see if I can have this Matrix-12 completely working. If so, then I have to start sourcing a replacement - which seems to be quite difficult. Any hints appreciated. Thanks for the feedback on the heat of the ICs. They get somewhat hot, but I can touch them without getting burned, so it is probably OK. The power supply regulators also get somewhat hot, but the hearsinks seems to be able to handle it. Terje Winther terje.winther@... |
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Re: only one board active
Terje Winther
Hi all,
Thank you very much for all the feedback and the hints of what to do. After a day?s break from the Matrix-12, I once again got into it with renewed energy. I *might* have found the error, but I am not sure. To recapture: Today a took both voice cards and swapped positions of the "board ID" tag (strap). Earlier there was always voice 7 - 12 who failed, and after the swap, voice 1-6 failed. So there is no doubt now: There is an error on the voice card. I swapped the straps back to the original positions, and inserted the cards and tried a few other options: - I tried new 4051 ICs at UX06 and UX07 on one of the voices. No change. - I tried new TL084 at UX08 at one of the voices. No change. - U108 (LM311) have been swapped. No change. - I have swapped all critical ICs U812 to U815 with the working voice card. No change. - I have swapped the processor U907 and the timer IC U921 with the working voice card. No change. Voice card two (the upper card) fails on all 6 voices as regard to VCOs, VCFs and VCAs. It comes close, but not perfect (off by as much as 0,5 - 3 notes). On the other hand, this is what is working: - There is sound from all 12 voices (if I override the automatic tuning and turn all voices manually on) - All 12 voices responds to keyboard, levers and such - All 12 voices change sound according to the stored programs, and changes done on the front panel - All voices pass tuning of PW (Pulse Width) and RES (filter resonance) So I started backtracking to other ICs, and I might have found the error: U811, the 3140 DAC chip. If I swap this between the voice card with tuning error and the working voice card, the tuning error follow the chip. Kind of strange, since all other activities also goes through that chip, and all other activities work as they should. Moving ICs before and after U811 changes nothing, but moving the 3140 DAC makes the tuning error move as well. So I am tempted to borrow a 3140 chip from the other Matrix-12 to see if I can have this Matrix-12 completely working. If so, then I have to start sourcing a replacement - which seems to be quite difficult. Any hints appreciated. Thanks for the feedback on the heat of the ICs. They get somewhat hot, but I can touch them without getting burned, so it is probably OK. The power supply regulators also get somewhat hot, but the hearsinks seems to be able to handle it. Terje Winther terje.winther@... |
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Re: Xpander's memory of settings
开云体育Mr. Tobbe from KC ? P. Am 12.07.2012 00:18, schrieb Tobbe Bergman:
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Re: Fw: only one board active
开云体育Freeze spray common in europe too. P. Am 12.07.2012 08:53, schrieb Karl Schmeer:
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Re: Xpander's memory of settings
开云体育Confirmed ! I still have the 1st battery in my Xpander,- since I buyed it new. No leakage though,- and when I thought theres a replacement necessary, Ive found out the old is full up to now. Im sure it depends on usage of the Xpander/Matrix-12, if its been switched on all day for a few hrs,- the battery holds your patches for decades. P. Am 12.07.2012 09:42, schrieb Karl Schmeer:
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Re: Xpander's memory of settings
Hi Jeremy,
The RAM data ( patch/multi data?)?in the M12/Xpander is battery backed. As opposed to FLASH ROM which is common in more modern designs. The only problem with battery backed RAM is you have to replace the battery every so often. It offers a theoretically endless number of re-writes?( Patch Saves) . The Lithium battery used in the M12/ Xpander is one of the more durable and long lasting batteries?I have ever seen. I keep meaning to change mine but have not gotten around to it yet. It's been holding the patches fine since the late 1980's. I have seen?the same model battery leak once from a piece of test gear (not musical instrument) manufactured in 1981. It did not spill onto the board but developed some kind of white crystals around it's case. It still?worked fine but I replaced it anyway. You can get exact replacements from Digi-Key which pretty much ships worldwide. And I happen to know they have a several European? and far east distribution centers, if you need one right away. Best Karl Hi, Does anyone know how the Xpander stores its settings? If you turn it on and off, it keeps the settings, for years and years. Is there a long-life battery? Thanks for any explanations! Cheers, Jeremy. |
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Fw: only one board active
Hi Terje,
? It seems to me to be a systematic error somewhere that eludes me.These are analog switches which multiplex?the master DAC voltages to provide individual?sample and hold circuits for each parameter in a given voice. The resistor and capacitor networks?provide a means of holding the CV voltage while the multiplexer?moves to the next parameter. Analog switches are notorious for becoming leaky and failing, but if you have switched these out and the problem still exsists, then the problem is somewhare else. But as I now have swapped all the ICs in the critical positionsI see the Straps on the?voice board schematic?below?the 6809 CPU It appears you will have to move these in order to " switch voice boards" That looks like the best aproach to isolate the problem to at least " which board is failing" BTW: some of the ICs gets fairly hot. I have noticed that in otherThese are older technology digital and anlog integrated circuits and they do tend to run on the warmer side. The CPU and memory chips are running at maximum speed so they will run hot. One thing to remember is if you place your finger on an IC you are adding heat to the circuit and if you hold it there long enough ( more than say 4?secs) the chip will heat up. Unless we are talking about power supply components (ie Voltage regulators),?If they are burning your finger then yes, it's probably sourcing to much current to?the next stage it is connected to. One common trouble shooting technique is to spray?"Freeze spray" onto the chips one by one?until the circuit works.It's an?easy way to isolate a heat problem We can still get this in the US. But not sure about Europe. Usually obtained from an electronics supply house.??? Note: Don't spray this on the VCO/VCF chips because thses are temperature sensitive, and?obviously it would change the tuning. |
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Re: Xpander's memory of settings
Tobbe Bergman
There is a lithium battery that should be replaced every 10 year or so !
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Some say it can start to leak and damage vital components if it get too old ! I've had the old (that is soldered on the board) replaced with a battery holder that uses the same type of lithium battery as a PC for easy replacment without soldering.
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Re: Xpander's memory of settings
Yes,
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this is a battery Kris Le 11 juil. 2012 à 21:38, Jeremy Smith a écrit :
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Re: only one board active
I read again this thread, and I noticed that some functions passed the test. More interesting, the functions who are failling are all using the TL084 (x08 chip). You can try to reseat or replace one of them. It may be strange that the x08 chips are fried on all boards but...
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About the boards swaping between the two M12, I thought about it, but since the other one is ok, it may be nice to kept this one safe no ;-) If you try to swap the board, you may change board ID in order to have two different one. You can only use one of the two first straps position. Kris Le 10 juil. 2012 à 22:34, Terje Winther a écrit :
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Re: only one board active
Terje,
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?Do you still have the 2nd Matrix 12? Maybe you can try board swapping between them to help narrow the possibilities (for both synths). ?I'm also wondering with all of the things that you've tried already, if the problem is cable related, or maybe a ground reference issue. That's just a wild guess though. On Tue, Jul 10, 2012 at 3:34 PM, Terje Winther <terje.winther@...> wrote:
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Re: only one board active
Terje Winther
Hi Omar,
Good point! I have been working on it for two full days now, so I am probably a bit bewildered. I will let it rest for a day, get back to it and hopefully discover something the day after tomorrow. The idea about the jumpers seems like a good place to re-start the debugging. I can reconfigre them and see if there is any change. Terje Den 10. juli. 2012 kl. 17.17 skrev Omar:
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Re: only one board active
your goal is to rule out whether you have a bad board so that you're not wasting time thinking about or attempting to troubleshoot other areas outside of the voiceboards themselves. that's all im saying :)
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once you know that you have two good boards, then you can narrow down your focus on areas other than the boards. if you have a bad board, then you can narrow down your focus on the bad board. but until then, there's no point getting into details until you at least determine that. -o On Tue, Jul 10, 2012 at 10:56 AM, Terje Winther <terje.winther@...> wrote:
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Re: only one board active
Terje Winther
at this point its a process of elimination,Yes, this is what I am trying to do. There is sound from both voice cards. All 12 voices sound well, and after tuning one card is perfect, while the other one is almost in tune, but not quite. Some VCOs are off by a few notes, and some VCFs are audible different, but not much. With the scope I can follow all the sound paths, and I can follow the sound path of the tuning. All good. I have also followed all the digital control lines to see what they are doing, and they all seem to come through. I have swapped a lot of ICs between the voice cards, one by one, checking to see if there is any change. Still no change. It seems to me to be a systematic error somewhere that eludes me. There is a network of 6 sets of DACs around UX06 and UX07, leading through a resistor network to UX08 before going to the VCOs, VCF and VCA, but there is one set of these for each individual voice, and I find it hard to believe the the CV control for all voices would fail at the same time. But it is interesting, because the PW and Resonance passes tuning each time, and they uses another DAC (U816) that is common for all the 6 voices on the voice card. But as I now have swapped all the ICs in the critical positions between the card to no avail, I am not sure what to do next. I could shift the position of the ID strap. How many possible position are there for that thing? (It is really just a jumper). BTW: some of the ICs gets fairly hot. I have noticed that in other Oberheim synths as well (almost burned myself on a OB-8 once). Is that normal? I have checked power many times, so all power supply voltages, frequencies and reference internal voltages are correct, and so far I have found no short circuits. But still: they are somewhat hot. Terje Winther terje.winther@... |
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Re: only one board active
at this point its a process of elimination, working backwards from a known operational point and ruling out all factors along the way. -omar --- sent from iPhone On Jul 10, 2012, at 10:16 AM, Christophe JANOT <cjanot@...> wrote:
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Re: only one board active
but it could be bad enough to cause the tuning errors. Just because its generating sound I would not rule it out. -omar --- sent from iPhone On Jul 10, 2012, at 10:16 AM, Christophe JANOT <cjanot@...> wrote:
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Re: only one board active
Yes you can try to only swap the, but he said previously that the board is producing sounds. So, the cable may be ok. Envoyé de mon iPhone Le 10 juil. 2012 à 16:12, Omar Torres <holografique@...> a écrit?:
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Re: only one board active
Ok. so if this "ID" is set with the strap/cable, have tried just moving the cable? If moving? the cable changes the "path" then again its not your boards and you just have a bad cable! :) -omar --- sent from iPhone On Jul 10, 2012, at 10:05 AM, Terje Winther <terje.winther@...> wrote:
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Re: only one board active
Terje Winther
It has to be two boards, or the error message stops the machine.
Terje Den 10. juli. 2012 kl. 14.45 skrev Christophe JANOT:
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