freestompboxes.org

Greetings

This is my first post, but I follow the forum for a long time and the information contained here was already very useful for me.

Today I'm asking for help.
I'm having trouble repairing my MAXON DUE-400. It has a compressor, distortion, Chorus / Flanger and Delay effects.

The distortion and compressor effects are work great, but the Chorus / Flanger and Delay does not work. At the exit I have only the signal dry, not the wet signal. I checked the switching stage and everything okay.

Firstly, I checked the power supply and didn't found nothing suspect. The Chorus / Flanger LFO is running ok, but I do not understand how the delay work so I don't know what looking for.

I got the schematic for analog stage, but I didn't find the MC4101F datasheet!


Could someone has experience with this device and can give me a starting point for verification?

Thanks
Luciano S. T.

Hi

Attached are the schematic files and the steps for adjustment.

Following steps to adjust

[Digital CH / FL]
[A] - Clock Frequency: setting SR4 I can not reach more than 50kHz on CP4!
- OffSet voltage: OK

Since I could not adjust Clock Frequency I did not go through with the rest of the settings.

PS:
The LFO was not working so I replaced C133, C135, C136, C137, C138, C139 and the oscillator ran again.

Thanks
Luciano S. T.

Do you have an oscilloscope available? If not, get one first. Troubleshooting without in systems like these is a PITA.

Dirk_Hendrik wrote:Do you have an oscilloscope available? If not, get one first. Troubleshooting without in systems like these is a PITA.

Yes, I have an oscilloscope. I used it to find the LFO problem and then certify the solution!

For now I'm trying to get the correct frequency in CP4, the SR4 is ok, but I have a certain fluctuation at CP4 and I cannot get over 50 Khz!

By the way ...

I don't know how the MC4101F works, so I do not know what to expect in its pins!