[fictionman]

Hi there, I'm new here!

I used the FK's DC interface for a while to control the playback speed of a modded Walkman (as Hainbach does on his videos).
Everything was working fine, but 2 days ago, I hadn't used the FK for a long time, and I got into a jam.
However, when I connect the Driver output to my Walkman in PMW mode, unlike before, the Walkman's motor runs at a constant speed, a fairly high speed by the way: the "Intensity" knob no longer does something. 
And the red LED doesn't light up either. 
Has anyone encountered this problem before? If so, did you manage to solve it?
I precise I tried 3 different modded Walkmans, and the same thing happens with all of them.
Thank you for your insights, I can't wait to read you!


Cheers

[Quolcat]

https://www.youtube.com/watch?v=FFggnho5cg8

This is what you are doing right?


Did you tried to use the DC interface to power something that is not a walkman like a little motor or solenoid?

[batchas]

Same problem here. So I'm trying to troubleshoot for a friend. The DRIVER OUT seems kaputt. The LED is not lightning anymore.

The signal at the output is +1V max (PWM or PULSE), no matter the amplitude of the incoming signal at CV/Trig in.

Q16 does not seems ok.

I made a PDF with screenshots of the scope, unfortunately I don't see how to attach here :(
So I uploaded here: https://docdro.id/LnNfsQN

[Quolcat]

***SOLUTION***


Hello Batchas,

Thank you very much for the probes ad the full explained pdf; this make much faster for us the work :)
Looking at the pdf with the FK schematics we think that the issue is more the Q1 than Q16 as you suggest.  (you was very near to solve the puzzle ahahahah)
This may happen when you draw too current into the DC interface; which is probably what happened with the walkman in the other case.

Component Q1 is a transistor and you can change for the IRLML6344, which is the one appearing in the schematics too.
In the newer FK we use PJA3400 (package SOT-23) which is more difficult to find but more reliable.

Swapping it should solve the problem; if not remember that you can repair for free if is still under warranty, or by paying the service if is not; (which should be less expensive for you because we already found the issue XD )

Update us if you swap it and solve it :)


p.s. Under the text where you post you can attach any type of file you would like :)

[batchas]

***SOLUTION***


Hello Batchas,

Thank you very much for the probes ad the full explained pdf; this make much faster for us the work :)
Looking at the pdf with the FK schematics we think that the issue is more the Q1 than Q16 as you suggest.  (you was very near to solve the puzzle ahahahah)
This may happen when you draw too current into the DC interface; which is probably what happened with the walkman in the other case.

Component Q1 is a transistor and you can change for the IRLML6344, which is the one appearing in the schematics too.
In the newer FK we use PJA3400 (package SOT-23) which is more difficult to find but more reliable.

Swapping it should solve the problem; if not remember that you can repair for free if is still under warranty, or by paying the service if is not; (which should be less expensive for you because we already found the issue XD )

Update us if you swap it and solve it :)


p.s.  Under the text where you post you can attach any type of file you would like :)

Thanks a lot for your quick answer. I very much appreciate. I'll let you know when I did it, I need first to find the transistor cause I don't have this one in stock.

About post and text edit, attach file: yesterday I was unable to access the full text, only the quick edit. But today it's like magic. Everything's possible! Full editor and so on :)

---

BTW, how do I recognize the board if old or newer? I see PR2 written on it.

[batchas]

how do I recognize an old board version from a new version? I see PR2 written on the one I have in front of me.

[Quolcat]

how do I recognize an old board version from a new version? I see PR2 written on the one I have in front of me.

PR2 definitely means is one of the first in production;  also I was not meaning is new board; but probably some componet were swapped

but I can see for the soldering of component that are hands made; since the last years we don't hand solder anymore, and modern robots do that for us for a cleaner result  


https://www.youtube.com/watch?v=MR6RXK8S6qI                :D :D :D

https://www.youtube.com/watch?v=D_8Pma1vHmw

[batchas]

Danke :)
I ordered IRLML6344.

+ thx for the videos. Always a pleasure to hear Kraftwerk!!!

[batchas]

Danke :)
I ordered IRLML6344.

I changed Q1 and not the unit is working properly.