AW: [Doepfer_a100] A-110-4: LED for negative part is OFF most of time

From yahoo
Sent Mon, Feb 13th 2017, 12:29

Hello,

without external LFM signal the LED should light up white when you turn the
LFrq knob CCW. When you turn the LFrq knob CW the LED should light blue.
Otherwise the module is defective and has to be repaired.
As soon as an external LFM signal is applied the blue/light share depends
upon the position of the LFrq knob and the LFM level.

Best wishes
Dieter Doepfer


> -----Ursprüngliche Nachricht-----
> Von: xxxxxxx_xxxx@xxxxxxxxxxx.xxx [mailto:xxxxxxx_xxxx@xxxxxxxxxxx.xxx]
> Gesendet: Montag, 13. Februar 2017 09:00
> An: xxxxxxx_xxxx@xxxxxxxxxxx.xxx
> Betreff: [Doepfer_a100] A-110-4: LED for negative part is OFF most of
> time
>
>
> Hello there,
>
> This is my first post, and I am sorry for writing message as follows.
> But, I would like to have any advice or suggestion for my A-110-4SE,
> which seems to malfunction.
>
> A few months ago,  I accidentally touched its circuit board while it
> was powered. Since then my A-110-4 did not generate the negative part.
> Specifically, with Lfrq knob being around the center, only the half
> (from the positive part) of modulation was heard. It sounded like "the
> half of the modulation is gone."  The bicolor led was only lit in blue
> when the positive part is modulated.
>
> As I have no knowledge about the circuit, all I could do was to
> replace all ICs with the new ones, and I did. After replacing all the
> ICs, and all the calibration procedures documented in
> "A110_4_trimming_potentiometers.pdf" being done,  the unit seemed to
> revert to its healthy state, in terms of the sound I heard.
>
> However, the led still does not work properly. The led is *rarely* lit
> in white. Currently, the led is either lit in blue, or off most of the
> time, and occasionally lit in white.
>
> So, my concern is that this irregular behavior the led may cause
> another trouble or fault.  Is it ok to keep using it, or is there any
> part in the circuit I should investigate, or is it better to ask the
> Doepfer for repair?
>
> Thank you very much.
>
> Regards,
> Ryuichi Tamura
>
>
> ------------------------------------
> Posted by: Ryuichi Tamura <xx.xxxxxx@xxxxx.xxx>
> ------------------------------------
>
>
> ------------------------------------
>
> Yahoo Groups Links
>
>
>



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