Polysix - Arpeggiator - Hilfe bei der Fehlersuche

[MacroDX]

Hallo Zusammen,
ich bin mit einem netten Dänen in Kontakt, ursprünglich wegen meiner CS15D Mod. Er versucht aber gerade seinen Polysix zum Laufen zu bekommen und ich weiss da erstmal nicht direkt wo gucken.
Der Herr scheint so wie ich ein ambitionierter Bastler zu sein und ich würde ihm gerne helfen.
Daher dachte ich, ich poste seine Fehlerbeschreibung hier und evtl. findet sich ja jemand, der weiterhelfen kann/mag? @fanwander vielleicht, wenn du mal Muse hast? Du kennst den P6 ja glaub ich ziemlich gut

When I power on the Polysix it will start of with a sound increasing in volume. 2 presses on Hold or 1 press on Arpeggiator will silence it. After that you can play and edit the sound. Hold will function as it is supposed to.
When I hit the arpeggiator button it will start immediately without any keys pressed. And it seems to me that it is playing the same notes every time. But you can change the notes that it play by pressing keys, but it seems to me that the same memorized notes will still be a part of the mix. Latch on does make a difference as it will keep playing the pressed keys along with the memorized notes I guess...
So I am suspecting that the functionality to hold the notes to be arpeggiated in memory are faulty or something more closely related to the arpeggiator.

Aus der Hüfte raus würde ich ein fehöerhaftes Address Latch/Multiplexer vermuten, hab aber erstmal keine Idee welches man sich da mal anschauen müsste.

Danke schonmal für eure Mithilfe

 

[fanwander]

Ziemlich eindeutig ein Batterieschaden. Oder?

 

[MacroDX]

Ziemlich eindeutig ein Batterieschaden. Oder?

Geh ich mal von aus, hab‘s aber noch nicht gesehen. Er hatte es zunächst auch so geschildert als würden Hold und latch nicht richtig funktionieren und da hatte ich auf 366 IC 31 getippt. Muss ihn auch nochmal fragen ob das jetzt alles ist oder es sonstige Fehler gibt.

 

[PeterSix]

Hallo, danke für ihren hilfe! Ich bin der Däne mit Polysix probleme Ich will im english schreiben als mein deutsch ist schlecht :/

I bought the Polysix knowing that it had a battery-problem. I regard the battery-problem rather mild. The corrosion hadn't travelled through the connectors and the damage seemed very local. I used the guidance from Oldcrows webpage and cleaned the PCB well - replaced attacked components and rewired damaged traces. But I might have missed something. I exchanged IC31(74LS08) on the KLM-367 PCB, a row-resistor and added a coin-cell battery-holder and battery.

Thanks!

 

[binary tubes]

Schade das Florian dafür keinen Reparaturleitfaden herausbringt, ...

... So wie die Dieter Korp Serie, ...
... Jetzt helfe ich mir selbst.


Bei mir war ein Dauersound, wegen einem defekten Envelope Chip.

 

[PeterSix]

Yesterday I started to wonder what it might be that start the arpeggiator constantly and I then I thought of the keyboard. I new that it had a few bad keys but had postponed that to the thorough cleaning when everything worked. I tried unplugging the keyboard and the synth started without the usual tone! Progress I guess. I then decided that I had to clean/repair the keys before doing any error-finding. When hitting the keys to identify the bad ones - all of them actually started working. With all of them working - the synth started with the keyboard attached and without any sound (because no keys pressed). And the arpeggiator works as it is supposed to - I guess So I guess that the key-contacts must have shortcurcuited somehow and triggered the arpeggiator ....? Maybe this a newbie-lesson and something that you would normally check first - know I learned that - he he

I still have an issue - with the synth forgetting the patches that I save after a day or so - I will look into that now.

Thanks for your help!

 

[MacroDX]

Bei mir war ein Dauersound, wegen einem defekten Envelope Chip.

Irgendwas in der Richtung hatte ich zunächst vermutet, aber wie Peter oben schrieb, war es wohl ausgelöst urch einen Dauerkontakt im Keyboard. Da wäre meine Vermutung jetzt nicht unbedingt hingefallen, da ich bei dieser Art Kontakte immmer nur das Problem hatte, dass eben kein Kontakt mehr zustande kam. Das es auch mal umgekehrt sein könnte war mir nicht so gewahr

 

[MacroDX]

I still have an issue - with the synth forgetting the patches that I save after a day or so - I will look into that now.

Are you sure that your battery replacement is working correctly? Are there 3V at 367 - IC32/18 even when the unit is switched off?

 

[PeterSix]

Hi MacroDX, hmm no... I have absolutely zero volts when I meassure from IC32/18 (VDD) to IC32/9 (GND). Thanks! Better check my battery replacement as you suggest!

 

[PeterSix]

Well, I checked my battery replacement and reinserted the battery and it actually measures 2.9V over IC32/18 (VDD) to IC32/9 (GND). I have reloaded the presets sounds to the (through tape) and after turning the synth off and on they are still there. Will check if they are still there when I get back from work...

 

[MacroDX]

Will check if they are still there when I get back from work...

And if they are does that mean your Polysix is back in full?

 

[PeterSix]

Yes, I would think so, but I will do some additional cleaning and I haven't fully checked everything...

 

[PeterSix]

Hi MacroDX, well no, I am not done yet :/ The voltage on the memory chip is still 2.9V but now after about 7 hours idle the sounds are reset... I am inclined to buy a new memory-chip and see if that will fix it. But I should probably go through the traces again and see if there is a loose connection that could cause a drop-out of power from the battery to the memory-chip.

 

[MacroDX]

Traces that have been affected by battery acid can still degrade even after a cleansing. Please check whether the battery cell itself is at 2.9V itself. If it is at a higher voltage, e.g 3V that could indicate that the traces are degenerated and act as a resistor preventing enough power to reach the memory chip.
I do not think that the memory itself is broken.

 

[binary tubes]

Irgendwas in der Richtung hatte ich zunächst vermutet, aber wie Peter oben schrieb, war es wohl ausgelöst urch einen Dauerkontakt im Keyboard. Da wäre meine Vermutung jetzt nicht unbedingt hingefallen, da ich bei dieser Art Kontakte immmer nur das Problem hatte, dass eben kein Kontakt mehr zustande kam. Das es auch mal umgekehrt sein könnte war mir nicht so gewahr

Okay, I get it. When you press a key, you start an envelope. If you unplug the keyboard, it should be gone by the time the keyboard generates this error.

Traces that have been affected by battery acid can still degrade even after a cleansing. Please check whether the battery cell itself is at 2.9V itself. If it is at a higher voltage, e.g 3V that could indicate that the traces are degenerated and act as a resistor preventing enough power to reach the memory chip.
I do not think that the memory itself is broken.

Have you solved the problem with the continuous sound?

It has little to do with memory. As I understand it, you still have the original battery inside?
You should remove it as soon as possible to protect the device. If it's not already defective.

There are good instructions on the internet on how to deactivate the charging circuit and install a Lithium cell, or you can regrind such a battery in a safe place.

But also Duracell never leaks, and in my case it has been the batteries that constantly leak for years, unlike others.

 

[MacroDX]

Have you solved the problem with the continuous sound?

Yo, das war die Sache mit dem Dauerkontakt aufm Keyboard

As I understand it, you still have the original battery inside?

Nö, Peter hat oben geschrieben dass er eine Batteriersatzschaltung für Knopfzelle eingebaut hat. Das aktuelle und offenbar mittlerweile auch gelöste Problem ist, dass die Batteriespannung nicht am Memory ankommt.

 

[PeterSix]

Hi Binary Tubes and MacroDX, yes MacroDX is correct my only remaining issue is the synth not being able to persist patches for a longer period of time. I do not know yet how long, but more than 1 hour and less than a 24 hours. The voltage on the memory chip is 2.9Volts. The coincell battery is 3V - I guess the drop in voltage is caused by the diode inserted in the curcuit. Normally the voltage on the memory-chip (when synth is powered) 5V, but following the instructions by OldCrows webpage it should be okay with 3V.... Thanks!

 

[MacroDX]

The voltage on the memory chip is 2.9Volts. The coincell battery is 3V - I guess the drop in voltage is caused by the diode inserted in the curcuit.

Doesn´t matter. According to the datasheet the data retention voltage can be as low as 2V. So maybe your memory chip really is faulty? I am not an expert here though, but this sounds familiar

 

[PeterSix]

It's a fairly easy thing to try so I have ordered a new one

 

[PeterSix]

An update from me: I finally got a new replacement memory-chip and replaced it in the Polysix (and put in a socket). I then turned on the synth and it made sound and I was able to alter the sounds and so on. I then went on to test the memory by loading in patches from TAPE, so I put the synth in TAPE ENABLE mode. By doing that all leds lighted up and remains turned on whenever the synth is powered. It does not make any sound and I can not bring it out of that state by pushing any buttons (to my knowledge).
From searching the web I have found indications that it might need a reset. The Service Manual describes a procedure where you connect a 56kohm resister on pins on PCB KLM-376 and you then will be able to adjust PCB KLM-367 and the adjustment will be indicated in the LEDS...? Any input is greatly appreciated

 

[fanwander]

Does it boot up fine, if you do not set the tape enable to on?

The reset adjustment with VR1 on KLM367 is something completely different. It has nothing to do with resetting the RAM.

 

[PeterSix]

Does it boot up fine, if you do not set the tape enable to on?

No, it boots up into the same state no matter what I do...

 

[fanwander]

Then your trouble is something different. I assume, than one CMOS after the other dies due to the battery leakage. You may find today one broken and in 6 months the next one will get belly up... I'd go for a KLM367 replacement board.

 

[PeterSix]

But dont you think that it is more likely that I either messed something up - or the fix of the memory-chip exposed a new error? I had it functioning with the exception of long-time-memory (it lost patches after some hours).
New PCB is tempting, but I am considering changing the 4000-series IC's that I have read are errorprone...

 

[MacroDX]

Hello Peter,
sorry to hear that, that´s an unfortunate setback. But I am certain that you´ll get it up and running eventually

or the fix of the memory-chip exposed a new error?

That is very likely, although fanwander also has a point. It may well happen that a component that has been affected by the battery leakeage goes south after a while. I however haven´t had any issues with neither the Poly 61 nor the Opera 6 that I´verecovered from severe battery damage. It can become a tedious task though. With the Opera 6 I eventually ended up following every single trace with a continuity tester and hand wired any suspicious track.
You should definatley check the reset circuit of the CPU.

 

[StormB]

Hallo alle zusammen ,
wußte jetzt nicht ob ich einen eigenen Beitrag verfassen soll oder ob ich es hier rein Poste,
denn ich hab auch Probleme mit meinem PolySix in der ARP Sektion
zu meinem problem:
wenn ich die Arp Taste Aktiv schalte leuchtet die Led nicht !
wenn ich an dem Speed Regler drehe reagiert er nicht direkt dauert ne 10tl sek manchmal bleibt er auch für 1 sek stehen und dann dudelt er wieder los
jetzt dachte ich erst an den Speed poti bzw an den 555 timer
vielen Dank im voraus
StormB
Nachtrag Probleme gelöst IC 01 auf dem 366 Board war defekt und der Speed Poti mußte getauscht werden , dabei hab ich auch gleich Taster ausgetauscht die nicht richtig funktioniert haben

 

[PeterSix]

Hi MacroDX and Sequencer.de

sorry to hear that, that´s an unfortunate setback. But I am certain that you´ll get it up and running eventually

Thanks for the trust you put in me Yeah, not what I had hoped for

That is very likely, although fanwander also has a point. It may well happen that a component that has been affected by the battery leakeage goes south after a while. I however haven´t had any issues with neither the Poly 61 nor the Opera 6 that I´verecovered from severe battery damage. It can become a tedious task though. With the Opera 6 I eventually ended up following every single trace with a continuity tester and hand wired any suspicious track.
You should definatley check the reset circuit of the CPU.

The battery damage on my Polysix was very light. I have cleaned it with vinegar and demineralized water and alcohol. But yes, I agree the sensible thing to do would be to grab a new replacement PCB (KLM-367a). But what if the problem is not with the KLM-367A PCB and I e.g. buy a very expensive replacement PCB from KIWI and I still have a broken Polysix (I know that there are cheaper alternatives like synthronics.de).

So since last I have only tried replacing the memory-chip with another one (I bought two), but with no luck. All leds still light up after powering up (actually the first time all leds light up and when powering off and on again only the leds in the programmer section lights up).

I have done some continuity testing of my repairs on KLM-367A, but haven't found any errors - I have checked the power supply again and it meassures fine.

I have found some ceramic capacitors that look suspicious - I can't tell if they are leaking gunk or if they have been glued to the pcb. I suspect them to be bad - see C20 on picture below. On two other ceramic capacitors there where like a tiny drop of metal on one of the capacitors legs...(see C37 on picture below)?
So I have ordered a lot of components - actually more or less all components for the PCB - I expect to learn a lot and hopefully get it fixed - or get frustrated and old too fast .

When receiving components I will start by checking the reset circuit from the service manual. Then I will try to follow the path of the "TAPE ENABLE" and exchange IC's along the way. Probably all suspicious ceramic capacitors first.
I will keep you updated and you should be very welcome to give me hints and advice! (I can more or less understand german, but not really write it, sorry).

 

[MacroDX]

@PeterSix Well, I think ceramic caps contain nothing to leak, although that crystal stuff in the second picture looks strange, have never seen that before. Also I don‘t believe that one would glue ceramic caps to the pcb. This is most likely some sort edof gunk, but not necessarily emitted by the the cap.

Another idea here: Does the current behaviour occur always or maybe only when the lid is closed? You should give that a try. My Polysix once showed a similar behavior when I accidentally squished a bunch of cables.

 

[fanwander]

@PeterSix
Are you the one who is discussing a very similar issue on the Vintage Korg list with Bob Grieb?

 

[PeterSix]

Well, I think ceramic caps contain nothing to leak, although that crystal stuff in the second picture looks strange, have never seen that before. Also I don‘t believe that one would glue ceramic caps to the pcb. This is most likely some sort edof gunk, but not necessarily emitted by the the cap.

I agree I am in the process of exchanging the bad ones and some potential bad IC's. My approach is not random but not highly scientific either I am replacing IC's: IC30, IC26, IC34 (IC31 was already changed in relation to batteryrepair) and suspicius ceramic capacitors. I have chosen these IC's as they seem to be in center of communication between CPU and memory and they are known to break down - and IC30 has been close to batterydamage. I am NOT changing one component at a time as plugging the PCB in and out of the synth would be time-consuming and would put extra stress on wires and connectors - I think...

Another idea here: Does the current behaviour occur always or maybe only when the lid is closed? You should give that a try. My Polysix once showed a similar behavior when I accidentally squished a bunch of cables.

That is a fair point and I experienced that when repairing my Poly61, but I always have the lid open and have tried wiggling the wires to identify any bad connections.
Also I think that it is important to remember that the error occurred instantly when I turned the TAPE ENABLE switch on (after having replaced the memory-chip). So I assume that it is related to that. In relation to that when I read the diagram KLM-367 as a novice I am in doubt whether lines are crossing or connecting - e.g as on below picture where the red arrow points:


Hope to get on with it tonight ...