Have you folks mixed this up with the mail and build threads, or is discourse being flaky?
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I think I started with a comment about the stripboard design and let it morph into a diary about obtaining the synth chips. In retrospect I should have made a new thread.
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I had the same problem Iāve been checking my circuit over for days with circuit tester checking all the values are right was proper scratching my nut over it but in the end turned out to be one of my potentiometers were faulty took me ages to even think of checking them, so I changed the pulse width potentiometer and it works perfect now, if your chip is getting hot thereās a problem with circuit and also probably fried the chip as Iāve also done the same thing I bought 5 as I thought Iād end up buggering a few so wasnāt a big problem lol if thereās nothing wrong with the circuit it shouldnāt get hot even if the chip is faulty so Iād make sure your faulty chip isnāt getting hot before inserting a new 1
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I have found that once you get them hot its best just to bin them [ icās ] , damage is done and they wonāt last even if they seem to be working .
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Hey, did you find what your issue was? I have exactly the same problem with a Pulse out, checked everything and nothing comes out. Tested two ICās, it doesnāt get hot but yet no Pulse output :/// Thanks
welcome !
maybe some answers here
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Which schematic/layout are you working with? Simple or performance? Stripboard or PCB? I would triple check your connections as that has been the primary cause for many of my issues (including the pulse output of the 3340 VCO where the solder I was initially using was worse than anything). If it is just the pulse output that isnāt working - your issue obviously lies among the PW, PWM, or Pulse pathing, so check there first!
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Thank you and apologies for the lack of info.
I use slightly modified (more compact) LMNC vero layout. Been checking everything for a whole day, but i understand that the mistake is somewhere in the wiring. I have two question, that i think will help me:
- Should i get a Pulse output (pin 4) without using PW to Pin 5?
- Is it possible to damage the IC in a way that only a Pulse part will stop working?
Thank you!
No worries, I was literally in the same boat of a messed up square wave like a week ago! Are you able to send pictures/layouts/schematics of the circuit?
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As far as I can tell, Iāve always seen pulse outputs on the as3340 with PW control. However, that I am not too sure about, so someone else might be better suited to answer that question. Are you using PW control in your circuit?
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Itās not likely to have just damaged the pulse output, unless there has been some sort of physical damage to it such as breaking the leg of the IC itself.
Have you tested the triangle and sawtooth outputs? If those are good, then that narrows the scope like I mentioned earlier.
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From datasheet:
0 V gets you 0% pulse width. You need +2.5 V for a square wave. (Thatās with Vcc = +15 V, I think itās +2 V with Vcc = +12 V.)
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Great. Really helpful. So i do need to feed a PW voltages in order to get something from pin 4. Will investigate further. Thanks 
I fried a couple of these chips in a similar way. I found that when it gets hot, thatās usually because thereās something wrong with the negative voltage on pin 3. I found the best way to fix this issue is applying -5v to pin 3, instead of -12 through a resistor.
I was getting discouraged too, Iām still having trouble getting it working how I want, but keep at it! Youāll get there!
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