Don,
Welcome to the World of KLM367 troubleshooting!
Shame the MUX pair aren't socketed as you could switch them around and see
if, for instance, the VCF cutoff problem moved to the PW/PWM output. As
these two are just 4000 series CMOS logic and it might be worth taking them
out, soldering in sockets and replace them with a nice pair of NXT HEF4051s,
etc. The old ones are almost 30 years old. Doesn't complimentary metal oxide
have a shelf life?!
If you are wondering how the analogue data is clocked back into the circuit
a pulse train appears at the junction of R72 and D10. This is used to
program the mask ROM on test pin T0. So you should see data here from the
multiplexor end on the KLM369.
Cheers,
Andy
On 26/01/2010 23:27, "backshall1 (dsl)" <backshall1@bellsouth.net> wrote:
> This thing is making me crazy. I checked the D00-D07 bus several times with
> a ohmmeter from CN10 to IC 24,26,30,31,33, 28, 29, 34, 35 and can't see a
> problem. With the oscilloscope, there is a decent signal on every pin of
> every chip, although I couldn't say if it is correct. Unless there is some
> crosstalk between data lines somehow, I don't think there's a problem here.
> I found some problems with the schematic:
> IC24 is mislabelled as IC34,
> CN10 has two pins labelled D06 and no D07,
> IC23 shows pins 5 and 6 connected. They are not.
>
> I went back to the panel knobs and checked for -5v to +5v from each of them.
> That looks okay. Then it goes into the MUX, and comes out really messed up.
> As expected, the "Data" line from the MUX chips looks like a set of random
> analog voltage steps, but each knob does not seem to control just one step.
> The knobs that work change 2 different "steps", the knobs that do nothing
> also change nothing, and the knobs that are controlling more than one
> parameter are changing more than 2 steps. It seems some knobs are not being
> read at all and others are being read more than once. Seems like a timing
> problem with the signals on A,B,C,Inh1 and Inh2. These lines also check out
> okay back to all ICs they are connected to. My old single-trace Heathkit
> oscilloscope (built it myself) is not up to the task of analyzing relative
> timings of these signals so I'm looking for a 4 channel scope on Ebay.
> Just for grins, I popped a different 8048 CPU from another dead Polysix into
> this one. It didn't change any symptoms.
>
> I did some more careful measurements of which knob is changing what, as seen
> on the outputs of ICs 7,9,10,11,12,13,14,16.
> Effect Speed - does nothing,
> VCF Cutoff - does nothing,
> EG Int - does nothing,
> Res - changes Res and Attack,
> Attack - does nothing,
> Decay - changes Decay and Sustain,
> Sustain - does nothing,
> Release - OK,
> KB Track - OK,
> PW/PWM - OK,
> PWM Speed - OK,
> MG Freq - OK,
> MG Delay - changes MG Delay and EG Int,
> MG Level - changes MG Level and VCF Cutoff.
>
> It's easy to see where the D/A conversion is on IC33, but where does the A/D
> occur? How do knob settings get converted into something that can be stored
> in memory?
> Thanks,
> Don B.
>
> _____
>
> From: PolySix@yahoogroups.com [mailto:PolySix@yahoogroups.com] On Behalf Of
> Andrew Jury
> Sent: Sunday, January 17, 2010 9:37 AM
> To: PolySix@yahoogroups.com
> Subject: Re: [PolySix] Wrong functions controlled by knobs?
>
>
>
>
> Use CN10 as a reference point and make sure DO0-7 connects to every
> terminating IC which requires access to the data bus. There are plenty of
> them! When you measure use the metalwork of the connector and the pins of
> the ICs as your test points, not the solder side. I have seen pads connected
> before which do not connect to the pins themselves. Also, another problem
> which comes up time after time is hidden battery dielectric leaked under the
> CPU's holder. I generally remove, clean and replace these as a matter of
> course.
>
> Good luck,
> Andy
>
> On 17/01/2010 14:19, "backshall1 (dsl)" <backshall1@bellsout
> <mailto:backshall1%40bellsouth.net> h.net> wrote:
>
>> On the KLM 367 between some specific chips? I started checking resistance
>> from the 14051s on the panel boards to the processor on the 367 board to
>> verify A,B,C,INH1,INH2 getting through CN11 okay. It looks good.
>> Don B.
>>
>> _____
>>
>> From: PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com
> [mailto:PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com] On
> Behalf Of
>> Andrew Jury
>> Sent: Sunday, January 17, 2010 8:10 AM
>> To: PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com
>> Subject: Re: [PolySix] Wrong functions controlled by knobs?
>>
>>
>>
>>
>> Ah, sorry Don, I misread that in a hurry, I thought you were setting up
> the
>> a/d converter. If only Leds 1-5 light then pay special attention to bits
> DO5
>> thru DO7!
>>
>> Let us know how you get on.
>>
>> Andy
>>
>> On 17/01/2010 12:57, "backshall1 (dsl)" <backshall1@bellsout
>> <mailto:backshall1%40bellsouth.net> h.net> wrote:
>>
>>> Hi Andy,
>>> I'll check out the data bus and inhibits. No, the calibration did not go
>>> well. LEDs 1 and 8 are supposed to light up, and I could only get 1 and
> 5.
>>> Thanks,
>>> Don B.
>>>
>>> _____
>>>
>>> From: PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com
>> [mailto:PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com] On
>> Behalf Of
>>> Andrew Jury
>>> Sent: Sunday, January 17, 2010 7:35 AM
>>> To: PolySix@yahoogroups <mailto:PolySix%40yahoogroups.com> .com
>>> Subject: Re: [PolySix] Wrong functions controlled by knobs?
>>>
>>>
>>>
>>>
>>> Hi Don,
>>>
>>> You almost certainly have track disconnections. Try and focus in on two
>>> places of the 367. First the data bus DO0-DO7 and the multiplex address
>> bus
>>> INH1-3. Using your scope scope ensure that you have at least what look
>> like
>>> trains¹ of data pulse when you operate the controls. I find when dealing
>>> with multiple problems like this it pays to select one of the problems
> and
>>> focus in on it. Usually everything else will start to become apparent as
>> you
>>> make progress. Before you start, however, are you able to perform the
>> reset
>>> calibration procedure correctly? If you can verify this then we can
>> proceed!
>>>
>>> Cheers,
>>> Andy
>>>
>>> On 16/01/2010 13:56, "longenough2002" <backshall1@bellsout
>>> <mailto:backshall1%40bellsouth.net> h.net> wrote:
>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Just got a Polysix in with some bizarre symptoms. It had an old battery
>>>> in it that looked like it had just started to leak. Only a couple of
>>>> traces had some black spots and still checked out okay with an ohmmeter.
>>>> I put in a cr2032 and diode and it is saving patches okay. It's not
>>>> until I twiddle some knobs that things start to get weird. Here is what
>>>> works: Output, Bend, Tune, VCO, VCA, Arpeggiator, Key Assign, Programmer
>>>> sections all OK. Problem sections: MG, VCF, EG, Effects. By Section: MG
>>>> - Frequency, Delay and Mod work, but Level seems to be controlling VCF
>>>> Cutoff, not modulation intensity. VCF - Cutoff does nothing, Resonance
>>>> works when set between 5 and 10, but seems to control Attack when set
>>>> between 0 and 5, EG Intensity does nothing, KBD Track works. EG - Attack
>>>> does nothing, Decay works, but in reverse, as if EG Intensity is in the
>>>> negative range. Release works between 5 and 10 but seems to do nothing
>>>> between 0 and 5. Effects - switch works, but Intensity does nothing.
>>>> It would seem the D/A is having serious problems, and I can't get LEDs 1
>>>> and 8 to light up during the reset procedure. I get 1 and 5. I wish the
>>>> service manual had some voltages to measure, instead of just watching
>>>> lights. The +/-15 and +/-5v supplies look good. Anybody have ideas where
>>>> to start debugging this? I have a scope and multimeter, but no logic
>>>> analyzer. Thanks for any assistance you can provide. Don B.
>>>>
>>>> [Non-text portions of this message have been removed]
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>> [Non-text portions of this message have been removed]
>>>
>>>
>>>
>>>
>>>
>>>
>>> [Non-text portions of this message have been removed]
>>>
>>>
>>>
>>> ------------------------------------
>>>
>>> PolySix "Digiest" Page: http://www.acc
>> <http://www.acc <http://www.acc.umu.se/~amber/Poly6Yahoo>
> umu.se/~amber/Poly6Yahoo> umu.se/~amber/Poly6Yahoo! Groups
>> Links
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>> [Non-text portions of this message have been removed]
>>
>>
>>
>> ------------------------------------
>>
>> PolySix "Digiest" Page: http://www.acc
> <http://www.acc.umu.se/~amber/Poly6Yahoo> umu.se/~amber/Poly6Yahoo! Groups
> Links
>>
>>
>>
>
>
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
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