kacperpawluk wrote: I changeed IC31, IC32, IC33 and BA6110. Now everything works good! Thanks for help!

Kacper I think I have the same problem, It was working correctly bup after finishing the LT & MT the Tone and Snappy stopped working...

See below Probed SD;

MAIN VOICE OP


ACCENT


ENV 1


ENV 2


ENV 3


ENV 4


ENV 5


NOISE


VCO 1


VCO 2


Do I really need to change these IC's?

During my recent build I experienced the exact same issue with one of my boards. In my case it was just a cold/ loose soldering point in the SD section. I would definately check this first. Take your soldering iron and reheat all the points and maybe also apply a tiny bit of new solder on each point to be safe. It is very easy to get a bad connection. I experienced this to be one of the main reasons for a voice not working properly. Also check for solder bridges...

Thanks Dude, I originally had it but after the LT and MT build it no longer works...
https://www.instagram.com/p/BOoGICQgKjO/

hofmann25,

It seems that VCO1 on Snare is not working properly.
Could you probe IC36 pin 8 ?

PS: When you post scope screenshot, please provide vertical and horizontal scale

Best regards,
e-licktronic

IC39 was loose in the IC Socket (Those single row IC sockets are shit). I got Tone working but Snappy is still not working.

Changed out IC31. No difference. Waiting on a supply of 4006's (Anyone have a good supply in Australia or Asia?)


SD probed at IC 36 Pin8 Vertical and Horizontal are marked.


Ideas?

Thanks Vincent;)

> IC39 was loose in the IC Socket (Those single row IC sockets are shit)

Bend the even and odd IC legs a little in a different directions 2 times, so it will make a good contact.
Here is a quick sketch for better understanding (picrelated madskillz)

redstorm wrote:> IC39 was loose in the IC Socket (Those single row IC sockets are shit)

Bend the even and odd IC legs a little in a different directions 2 times, so it will make a good contact.
Here is a quick sketch for better understanding (picrelated madskillz)

Thanks man, beautiful artwork!

I'll give that a try. Thank you

I also have some masking tape that does not loose it's glue. Its designed for Labeling. I might tape the IC to the socket

I think I have a similar problem. Although, reading this topic, I see a bunch of different problems being described. I am going to think out loud a bit.

My noise is working (handclap sounds fine) and I think the bass drum, toms are also OK. But the snaredrum is not.

- TONE does nothing
- SNAPPY acts as a low-pass filter but there is almost no sound going through it. I can hear a sharpness when it is turned to the right which goes away on the left.

Looking at https://en.wikipedia.org/wiki/Low-pass_ ... ealization and the service manual I am pretty sure SNAPPY is really just the cutoff of an active lowpass filter for part of the snare sound. Looking at the block diagram in the service manual there are two noise-based components that should be added to the final sound, with different filters and envelopes (ENV 4, 5). The fact that my SNAPPY does almost nothing means that neither of the noise-based signals are being created.

The noise shaping follows a common path until IC40a. There there is a fork where some of it passes through a bit more of RC stuff I don't understand to the collector of Q48. The other part out of IC40a goes through what must be the 'high pass filter' of the block diagram (some active circuit involving IC39a) and into the collector of Q47. The outputs of Q47 and Q48 get summed just by being connected and pass through the SNAPPY IC39b variable active lowpass filter.

The TONE knob appears to be part of the ENV4 envelope generator circuit.

I suppose I should now look for filtered noise on the output of IC40a and for envelopes at D59 and D64. FWIW I already spent $27 including shipping to replace Q47 and Q48 with no effect.

jvq wrote: I suppose I should now look for filtered noise on the output of IC40a and for envelopes at D59 and D64.

I see the envelopes at D59/D64 on my crappy DSO 138 scope, and the noise at IC40a. Because the DSO 138 is so shitty it is hard to compare the waveforms at D59 with TONE fully open/closed; but right now I don't care so much if TONE is correctly modifying ENV4.

I will now look for a noise signal on the top leg of R298 (input to Q48 VCA) and the bottom leg of R278 (input to Q47).

If that goes nowhere I think I will take the main board out of the case so I can measure on the solder side and see what happens at the pins of Q47/Q48. I am going to be very bummed if the two 'new' 2SD1469 transistors I bought are broken. Let's hope it is a bad solder joint or something.