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WIGGLING 'LITE' IN GUEST MODE

208p build thread (papz's PCBs)
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page Previous  1, 2, 3 ... 13, 14, 15, 16  Next [all]
Author 208p build thread (papz's PCBs)
wedaman
Hello everyone.
I appreciate the dedicated work of papz.

Please help me install switch 11 (DIGIKEY PART # CKN 1008 - ND) on the motherboard.

Is the correct answer as shown below?
ON (triggerd) - OFF (off) - Momentary ON (one)
captnapalm
wedaman wrote:
Hello everyone.
I appreciate the dedicated work of papz.

Please help me install switch 11 (DIGIKEY PART # CKN 1008 - ND) on the motherboard.

Is the correct answer as shown below?
ON (triggerd) - OFF (off) - Momentary ON (one)


Yes that's correct. The momentary position should be when you depress the switch downward to the "one" setting.
wedaman
captnapalm wrote:
wedaman wrote:
Hello everyone.
I appreciate the dedicated work of papz.

Please help me install switch 11 (DIGIKEY PART # CKN 1008 - ND) on the motherboard.

Is the correct answer as shown below?
ON (triggerd) - OFF (off) - Momentary ON (one)


Yes that's correct. The momentary position should be when you depress the switch downward to the "one" setting.



Thanks! captnapalm.
tronotape
Should the fine tune knobs be set at noon when calibrating?
papz
When calibrating I set the CO fine tune fully CCW to make sure the lowest frequency possible is about 55Hz, if lower instability occurs sometimes, and the MO fine tune fully CW to have a comfortable range in audio frequencies.
wedaman
Hello everyone.

It is a question about calibration.
Where are the oscilloscopes connected when calibrating Buchla 208?
The ground is easy to understand. But at which point should each calibration be connected?
papz
Hi
I monitor the audio outputs for calibration.
wedaman
papz wrote:
Hi
I monitor the audio outputs for calibration.


I see. Thanks. Rockin' Banana!
Chaotic
First power up and testing. Love this machine. It seems like everything is functioning as it should. I have not calibrated it yet Rockin' Banana!
papz
thumbs up
Chaotic
I can almost say I have finished my 208 It's peanut butter jelly time!
Only one problem remaining.
Sometimes when I turn up headphone pot strange things happens. Distortion, noise, crackling and audio drop. The tuning is also affected. Turning down the pot restore the sound. Both line out and headphone are the same.
Visual inspected the values on the card.

My first thought was the headphone pot but I have tried another card 12 and then its ok.
Some ideas where I can start?
papz
Inspect solder joints.
Check values with a multimeter, comparing with the good working card 12.
tarandfeathers
Also measure across the monitor volume pot and check if there is DC across it.
fg
hello, simple question about the dpdt on on on,
which one is the good A or B ?



thanx for your answer
davebr
Chaotic wrote:
I can almost say I have finished my 208 It's peanut butter jelly time!
Only one problem remaining.
Sometimes when I turn up headphone pot strange things happens. Distortion, noise, crackling and audio drop. The tuning is also affected. Turning down the pot restore the sound. Both line out and headphone are the same.
Visual inspected the values on the card.

My first thought was the headphone pot but I have tried another card 12 and then its ok.
Some ideas where I can start?

Your LM380s are likely breaking into high frequency oscillation. That will draw significant power and affect the tuning and explain the noise. I'm not sure why both the headphone and line outs are affected unless the oscillations are disturbing other circuits.

Lots of things can affect oscillations including wrong part values and soldering. Check all the part values around IC3 and IC4. The parts will get hot when oscillating and can burn themselves out. You can lift one end of R17 and R33 to disconnect the LM380s and verify the problem goes away (you won't have any headphone output). Then put one resistor back in and verify, then the other. You can probably isolate it to one of the channels. R17 drives IC3 and R33 drives IC4. You know the problem is on Card12 since you substituted it. Good luck.
papz
The on-on-on switches should be C&K (available from Mouser, Digikey) or Taiway (available from Small Bear) to match the PCB trace that makes the short needed between 2 lugs for this type of switch.
Another manufacturer's ones might not work because the short is between 2 other lugs and the pinout is different.

A on your pic.
fg
ok A

big thanx for your answer
Chaotic
davebr wrote:
Chaotic wrote:
I can almost say I have finished my 208 It's peanut butter jelly time!
Only one problem remaining.
Sometimes when I turn up headphone pot strange things happens. Distortion, noise, crackling and audio drop. The tuning is also affected. Turning down the pot restore the sound. Both line out and headphone are the same.
Visual inspected the values on the card.

My first thought was the headphone pot but I have tried another card 12 and then its ok.
Some ideas where I can start?

Your LM380s are likely breaking into high frequency oscillation. That will draw significant power and affect the tuning and explain the noise. I'm not sure why both the headphone and line outs are affected unless the oscillations are disturbing other circuits.

Lots of things can affect oscillations including wrong part values and soldering. Check all the part values around IC3 and IC4. The parts will get hot when oscillating and can burn themselves out. You can lift one end of R17 and R33 to disconnect the LM380s and verify the problem goes away (you won't have any headphone output). Then put one resistor back in and verify, then the other. You can probably isolate it to one of the channels. R17 drives IC3 and R33 drives IC4. You know the problem is on Card12 since you substituted it. Good luck.


Thanks. Tried my card on my friendĀ“s 208 and it works. Couldnt see something wrong but resoldered all the solder joints and now its working. It had something with the 380s to do. They got very hot. Checked all the component values and they were ok
Now I hear some crosstalk from the osc and pulser with all signal pots down. I have read about it somewhere so now I have to read all the threads again. hihi

Edit #1: Tomorrow I will try to put a resistor in series to the led on the pulser. Maybe that will solve the leaking from it?
And try another psu. Now Im using a Blacet 500mA. I have a 800mA I can try.

Edit #2: The resistor solved most of the clicks from pulser and envelope.
Another psu had nothing to say. But I tried a shorting between noisy and quiet ground on the distro board and most of the CO leakage disappeared.
I know this should not be done but it seems like the leakage is better. Not gone but less audiable
Chaotic
The only issue now is the bleeding. Not only the MO, but the CO too.
It's quite noticeable when all pots and slider pointed at zero. And it disappear when I crank the output pot to about 4.
I tried to swap card #12 with my friendĀ“s roman card and then, no bleeding. Quiet.
I have checked the component values and they are the same.
Only the capacitor types are different. (same values)
Some ideas?
[img][/img]
papz
Are your cables to the distroboard thick enough ?
Chaotic
papz wrote:
Are your cables to the distroboard thick enough ?

I have used 1mm2 (AWG 17)
papz
This should be enough indeed.
The difference in behavior swapping cards 12 is weird, I'm not sure the capacitor type is in cause as long as the values are ok.
Since it's more noticeable when all pots and sliders are to 0, it looks ground related. Compare resistance between the cards 12 groundplane and Q and N grounds on the MB, with the module disconnected from the distroboard (shorted Q and N on this, right ?).
fg
hello, it's done and working !!!

just small question about a strange behaviour from the sequencer in "both mode" only, everything is ok in "front panel mode"
see the picture below.



any ideas ?

thanx a lot for all
papz
Did you use modern 4013's ? Some cause stages # errors. If yes, try and swap them with old ones such as V4013D, available on ebay .
fg
yes, i use a modern one i will try an old one

but it s working very well in "front panel mode" ? just instable in "both mode"
i think that is strange.

the rest is perfect !!! thanx again
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