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TM3030 problem with trigger and sound
MUFF WIGGLER Forum Index -> Oakley Sound Systems  
Author TM3030 problem with trigger and sound
morelius21
Hi

i have a tm3030, and i have a problem.

when I press a key , I can hear in the first moment, only the trigger or gate (just a kick sound) after i can hear the sound perfect. In the osciloscope i can see the waveform before de PCB switchwave, when i press de key, this waveform disappear and after arrive the wave again.

any idea ? my english is very bad sorry.

Thanks
Synthbuilder
My first thoughts are that the power supply is not doing its job. I'd check that R60 is definitely a 10R resistor and not something like 100R.

Tony
studyman
Hello,
i just finished my TM3030 issue 1, i know i'm late..wink but i've got a problem, all the leds are ok . When i play a midi sequence via my DAW i just ear a sound like a bass drum very short. I can ear that the note respond to the accent but just this sound at the same ton...i measured the power thru the U13 and i only have 14,8V. I use a 15V AC power supply (500mA-7,5 VA). I tried with an other power supply 15V 2,4A 36VA but i've got a very big sound of "masse" !!! i already checked the R40-R50 and R60....
Can you help me ....???
Thanks
Stuyman
Synthbuilder
studyman wrote:
i measured the power thru the U13 and i only have 14,8V. I use a 15V AC power supply (500mA-7,5 VA). I tried with an other power supply 15V 2,4A 36VA but i've got a very big sound of "masse" !!!


Pin 7 of U13 should be roughly 12V. Pin 1 of U13 should be around 5.33V. You should be able to adjust pin 1's voltage to exactly 5.33V by adjusting the trimmer PSU. If you can't get 5.33V then you probably have a fault with the components around U10. If you have 14.8V at pin 1 of U13, switch off and thoroughly check the components around U10 - maybe even replace U10.

Make sure your power supply is providing 15V AC and not DC. A 500mA power supply is plenty good enough but it does need to be an AC output. The bigger 36VA supply should work just fine but only if the output voltage is AC and not DC.

If you only have an DC output power supply then you need one with an 18V or 24V output.

Tony
studyman
ok i'll try with another supply...thanks
studyman
it's not easy to find in France a 15V AC transformer...wink
studyman
i've got a 19v DC 4,74A from an old computer is that would be ok ?
Synthbuilder
studyman wrote:
i've got a 19v DC 4,74A from an old computer is that would be ok ?


Possibly. The 19V is fine. But the 4.74A is huge and the TM3030 will be using only a fraction of that. This might mean your power supply won't work properly. Being a computer power supply it is almost certainly a switch mode design and these types of power supply have minimum loads. That means you have to take out a quite a bit of current for them to work properly and the TM3030 may not provide a big enough load to do that. Plus switch mode power supplies designed for computers are normally electrically noisy. Personally, I would not use it.

Look for a 18V or 24V DC output power pack.

Unfortunately, good quality AC output ones are rare in the UK too now - although Ebay is usually a good source of cheaper Chinese made ones.

Tony
studyman
hello,
i just received the right ac power, i changed Q5 Q4 and Q3...but i have the same problem...just a kick sound...i've got volume, accent, midi in.
I've got the 5,33v ...
what can i do more please....?
Pierre
Synthbuilder
Unfortunately, there are quite a number of things that can lead to you just getting clicks at the output.

What is the voltage at pin 7 of U13? It should be around 12V.

What is the voltage at pin 7 of U7? This should change depending on the note you play and will be from 1V to around 5V. High notes being higher voltages. If this is OK then the midi-CV section is working.

What are the voltages on pin 2, pin 12, pin 13 and pin 14 of U6? 13 and 14 should be 5.33V and 12 should be 4.6V or so. Pin 2 will be around 5.33V but will vary with the note played.

Tony
studyman
hello,
i'm sorry but maybe i didn't precise that i've a issue 1 board, the U6 is SSM2210 so there are only 8 pin... wink
Pierre
Synthbuilder
Sorry, didn't see that bit.

What are the voltages on pin 2, pin 6, pin 7 and pin 8 of U6? 7 and 8 should be 5.33V and 6 should be 4.6V or so. Pin 2 will be around 5.33V but will vary with the note played.

Are pins 7 on U13 and U7 correct though?

Tony
studyman
so i checked the voltage, here they are :
U6: pin2:5,33V/pin 6: 4,83V/pin 7: 5,34V/pin 8:5,34V with a variation between an octave 5,29-5,31
U7: pin 7 variation between 3 and 4 V
U13: pin7 11,83V
Synthbuilder
These voltages look good enough. So the problem is probably not with the circuitry around the pitch control voltage or nor the exponential convertor U6.

The oscillator may not be oscillating though. The next thing to check is the FET. It is imperative that you have the right FET in the right holes. The J201 should be in Q2 or the 2SK30 in Q1. Which one have you used?

Tony
studyman
Synthbuilder wrote:
These voltages look good enough. So the problem is probably not with the circuitry around the pitch control voltage or nor the exponential convertor U6.

The oscillator may not be oscillating though. The next thing to check is the FET. It is imperative that you have the right FET in the right holes. The J201 should be in Q2 or the 2SK30 in Q1. Which one have you used?

Tony


Hello,
i used a J201 in Q2, is there a possibility to test it ?
Synthbuilder
studyman wrote:
i used a J201 in Q2, is there a possibility to test it ?


Not without taking it out of the board. Do you have access to an oscilloscope? If not what is the DC voltage across R5? Measure between both ends of R5. What is the AC voltage across R5? This time use the AC volts setting on your meter.

If you do have a spare J201 it may be worthwhile swapping it with the one you have.

Tony
studyman
AC 16,5V
DC -8,19V
for R5 mesures

just a question....J201 FET and J201 JFET is the same thing ?
thanks
Synthbuilder
studyman wrote:
AC 16,5V


Are you sure about that one? A dead VCO would give around zero. A working one would be around 4V. 16.5V sounds too big.

Quote:
J201 FET and J201 JFET is the same thing ?


Yes. The J stands for junction and a JFET is normally just shortened to FET.

Tony
studyman
ok i'll check those values again, i think my voltmeter is a little bit tired...wink
studyman
maybe a stupid question but for the value i must put the power supply "ON" ? because that's what i did....
Synthbuilder
studyman wrote:
for the value i must put the power supply "ON" ?


Yes, when measuring voltages, both AC and DC, the unit should be switched on. When measuring any resistances then the unit should be switched off.

The problem with measuring AC voltages is that some meters do not do it very well. The AC range is often only there to measure voltages that come out of power supplies. They don't do audio frequencies very well. Even so, you should be able to tell whether something has an AC signal on it, if it comes up with something other than 0.00V.

Tony
studyman
ok but you asked me to measure at R5, so switched off...
studyman
so, i did the mesures with a new voltmeter,
switched power on thru R5: DC= + or - 8,20V and AC: 17V or 0v if i inverse the pointers...
studyman
i've just checked all my U and i saw a 6N139 instead of 6N137...is that bad ?
Synthbuilder
studyman wrote:
i've just checked all my U and i saw a 6N139 instead of 6N137...is that bad ?


If your midi is working then the 6N139 is working fine. I used 6N139 instead of 6N137 on the earlier builds.

Tony
Synthbuilder
studyman wrote:
so, i did the mesures with a new voltmeter,
switched power on thru R5: DC= + or - 8,20V and AC: 17V or 0v if i inverse the pointers...


That AC one is very odd. Can you measure it again. Leave it for a few seconds to stabilise. If you are indeed getting a value over 0.5V then your VCO is probably working. The fault is probably elsewhere in the circuit.

Tony
studyman
Hello,
i've just put the J201 and i've got th real sound !!!! great !!! BUT the sound of the 303 is with a big white noise on every notes !!
what's this next problem...?
Pierre
Synthbuilder
studyman wrote:
i've just put the J201 and i've got th real sound !!!! great !!! BUT the sound of the 303 is with a big white noise on every notes !!


White noise as in a loud hiss? If so, can you filter it with the cut-off and resonance control?

If the hiss does not change in tone when these controls are altered the fault is probably somewhere in the VCA or output stages of the filter. However, changing the J201 should not have affected this unless you have an intermittent fault somewhere.

Tony
studyman
hello,
effectively, this is a loud hiss and it doesn't change in tone when i cut the freq and reso
Pierre
Synthbuilder
Sorry Pierre I think I may have misunderstood your post above. So the TM3030 is now working as it should but with an additional hiss on top of the correct sound. Is that right?

If so, does the hiss turn on and off with the notes being played? Or is the TM3030 constantly hissing?

If it is always hissing you probably have a fault in the output circuitry. That is the circuitry around Q33 and Q34. Also Q35 could also be bad.

If is only hisses when the notes are being played then the fault could be in the VCA. Possibly U14 or U15.

Tony
studyman
hello,
i measured again the AC thru R5 and it's 18V in one way and 0v in the other way...
Pierre
studyman
yes hiss is only when the note is played
studyman
it's very strange because i measured R5 solded it's 2,8ohms and i unsolded it it's 10k !!!
studyman
2,8k...sorry
studyman
i've got the same problem with R3, on the board 14K and off the board 180K...i don't understand anything.... very frustrating
Synthbuilder
It is not possible to measure the resistance of any component while it is soldered into a circuit. All the other components connected to the resistor, and there are many, will have an affect and lower the actual value read on your meter. The only way you can measure resistance is to take the component out - although you can sometimes just lift one leg and measure between the lifted leg and the other end.

This is generally why we measure voltage around a circuit. But to understand these voltages you normally need a good knowledge of the operation of the circuit.

If your meter gives one AC voltage one way and another the other way then it is a poor meter. Sorry. All it is actually doing is measuring a DC voltage through a internal diode. It's really too simple for doing accurate measurements. Better meters are available that will measure it properly.

If you are hearing a hiss only when the notes are being played and not affected by the filter then I would suspect the VCA - this is either the CA3080 or the BA662.

However, it could be other things. The VCA always produces hiss - all electronic circuits do. If the audio level going into the VCA is somehow smaller than it should be then the hiss will start to be heard. Maybe R110 is the wrong value?

Tony
studyman
R110 is good, 2,2K, i'll try with a new CA3080 that i found in deutchland...
thanks for your patience .....wink
Pierre
studyman
yyyyeeeeaahhhh ! because you said that's possibly the VCA i cod the J201 (the buffer for the CA3080) if i understood the circuit....and that's it i ve the sound without the noise !!!!!! great great !!!!!! thanks Tony !!!!
nanners nanners nanners nanners nanners nanners nanners nanners nanners nanners nanners
Pierre
Synthbuilder
thumbs up
IKE753Z
I'm tracking down a very similar issue, as far as I can tell VCO is working correctly, waveforms look good and it has that wonderful 303 sound, but at the start of every single note (excluding slides of course) I get a massive click, like so:


I know full well that I was ripped off when I bought my power supply, forked over the money for a 24VDC 1A linear supply and got a 24VDC 600mA switch mode power supply instead. very frustrating

The only thing I can do to change the shape of the click is by adjusting the decay, in which case I can make it slightly longer.

Do you think this is caused by the power supply not providing power fast enough or do you think it's a problem with the VCA? All other voltages seem to be fine, I'm mildly suspicious that the 2SK30Y is not working correctly or is fake, but I wanted a second opinion before I started throwing more money at it.
Synthbuilder
It could be the power supply. Check your voltage readings on the 12V and 5.3V supply lines. If these are dipping obviously as a new note is triggered it is the power supply.

The TM3030's own power supply should filter out most of the noise present on any external supply.

The other thing to check is the waveform of the VCO as each note is triggered. If you continuously hit the same note then you should not see the VCO frequency change. In that scope trace shot it's difficult to see whether the VCO is changing or the output of the VCA is being affected by a very temporary large DC shift. If it is the VCO pitch that is changing, look for faults around the glide circuit particularly U8.

Tony
IKE753Z
Reporting back for the sake of those troubleshooting in the future:

Q18 (2SK30A-Y) WAS the problem and since replacing it my TM3030 functions beautifully!

Thanks for all your help and hard work Tony! we're not worthy

The documentation, board quality and technical support for this project was excellent!

The TM3030 is incredible! SlayerBadger!

(I'll probably be getting started on an Oakley modular based on how much I enjoyed this!) Mr. Green

-I
Synthbuilder
thumbs up Good to hear you got it working.

Tony
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