[sdiy] Help trouble shooting mfos echo rockit
JoeF
frey at radioles.com
Mon Nov 21 19:18:02 CET 2022
Doug, performing the test you asked for I get 5.37V at x27 and -3.76V at x28. Tx for the help! JoeF.
Get TypeApp for Android
On Nov 21, 2022, 10:43 AM, at 10:43 AM, Doug Forbes <dougforbes1 at gmail.com> wrote:
>Hi Joe,
>
>BN is -4.5 volts with respect to ground. Ground is the green wire shown
>
>in the panel wiring picture from your link below. Put the black wire
>from your meter on it and please tell me what you read on the black and
>
>the red wires from the battery that are marked X28 and X27 on the front
>
>panel.
>
>On 11/20/2022 6:17 PM, JoeF wrote:
>> Doug. Tx for the help. I am building the kit. Huh. Isn't BN ground in
>
>> this case?
>>
>>
>http://musicfromouterspace.com/analogsynth_new/ECHOROCKIT/ECHOROCKIT.php#:~:text=The%20Echo%20Rockit%20makes%20some,the%20palm%20of%20your%20hand.
>>
>> I have no bipolar power supply? I attached my multimeter black lead
>to
>> battery negative. Pin 6 on the 13600 is ground (BN). The only other
>> power supply is U2 which makes 5 volts for the PT2399.
>> I have wired mine as the front panel wiring diagram. JoeF.
>>
>>
>> Get TypeApp for Android <http://www.typeapp.com/r>
>> On Nov 20, 2022, at 8:09 PM, Doug Forbes <dougforbes1 at gmail.com>
>wrote:
>>
>> Joe, those voltages are all wrong. For example pin6 should read
>> negative with respect to ground. It's connected to the neg supply
>> voltage. Take a look at the second page attached. BN is neg and
>BP
>> is pos with respect to ground. If you're using a 9 volt battery
>> they should be -4.5 and +4.5 volts respectively.
>>
>>
>> On 11/20/2022 4:22 PM, JoeF wrote:
>>> Hello and tx again. So, I followed the schematic and there are
>>> indeed resistors before the labc inputs. They are 22K. I
>measured
>>> a voltage drop of 3.61V across them and calculate a current of
>>> 165micro amps. So, is that a reasonable value. I have also
>>> recorded the 13600 pin voltage values below.
>>> Starting at pin 1 and finishing at 16.
>>> 1.25-1
>>> 0-2
>>> 3.73-3
>>> 3.68-4
>>> 8.4-5
>>> 0-6
>>> 0.31-7
>>> 1.28-8
>>> 0.32-9
>>> 0.31-10
>>> 9.14-11
>>> 0.61-12
>>> 3.76-13
>>> 3.74-14
>>> 0-15
>>> 1.25-16
>>> I am pretty much under water here. I don't know whether these
>are
>>> appropriate values for this circuit or not. I can hear an audio
>>> signal on pin 3. And, I hear it on pin 8.
>>> Tx for the help. JoeF.
>>>
>>>
>>>
>>>
>>> Get TypeApp for Android <http://www.typeapp.com/r>
>>> On Nov 20, 2022, at 3:24 PM, Roman < modular at go2.pl> wrote:
>>>
>>> I don't have any schematics at hand so it's just basic
>>> guideline. There is something going into Iabc pin of
>LM13600.
>>> If it's a resistor, then simply measure voltage across that
>>> resistor and use Ohm law to calculate current. If it's
>>> supplied directly from PNP transistor's collector (most
>>> typical use) find a resistor that is going to emiter of that
>>> transistor, and do as previously described. In any scenario
>>> you may just desolder or cut the trace to Iabc pin and
>>> measure it with ampmeter. Or better yet, put a resistor
>there
>>> if there wasn't any, it can only help. 4k7 for starters. It
>>> will make future troubleshoting easier, not to mention it
>>> also prevents LM13600 from accidental smoking.
>>>
>>>
>>> Roman
>>>
>>>
>>>
>>> ---- Użytkownik JoeF napisał ----
>>>
>>> Roman and Pete, TY. Roman, I want to move to the next level.
>>> Could you pont the way to how to determine current flow. I
>>> know how to check voltage and perform audio traces but I
>>> don't know how to determine current. If it's not too
>>> difficult, could you explain or point to a site that would
>>> explain. Tx again. JoeF.
>>>
>>> Get TypeApp for Android <http://www.typeapp.com/r>
>>> On Nov 20, 2022, at 2:44 AM, Roman < modular at go2.pl> wrote:
>>>
>>> Measure the Iabc current going to LM13600 to check if
>>> they are open at all. Measure voltages at OTAs and
>opamps
>>> outputs to see if they are not terribly close to one of
>>> supply rails.
>>>
>>>
>>> Roman
>>>
>>>
>>>
>>> ---- Użytkownik JoeF napisał ----
>>>
>>> Hello all, not sure if this is the right place to ask
>for
>>> guidance but, I'll try. I have put together an Echo
>>> Rockit I got as a kit. And, of course I need to
>>> troubleshoot.
>>> This is an oscillator and external input into a VCF into
>>> a PT2399 delay. I am getting no sound at the output and
>I
>>> believe it is because the VCF is not functioning. I have
>>> audio traced a signal to the VCF from the input and the
>>> internal oscillator. And, I have jumped the signals
>>> around the VCF straight to the delay and then I get
>>> output and have verified the delay is operating as
>>> expected. I have correct power to all IC power pins. The
>>> transistors are getting power on their source pins.The
>>> <http://pins.The> IC in the VCF is an 13600 <tel:13600>D
>>> which I have spares of and have swapped to no avail. I
>>> have re-soldered the components in the VCF circuit. I
>>> don't have extras of the MPF102 transistors and am
>>> questioning whether I burned them up when I soldered
>them
>>> in? What do you think?
>>> What's next? Thanks for any advice in advance. JoeF.
>>>
>>> Get TypeApp for Android <http://www.typeapp.com/r>
>>>
>>>
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>> --
>>
>>
>>
>> Doug
>>
>>
>> Doug Forbes Page <http://sites.google.com/site/dougforbes1/home>
>>
>>
>--
>
>
>
>Doug
>
>
>Doug Forbes Page <http://sites.google.com/site/dougforbes1/home>
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