Sounds to me like a defective LED. If you are familiar with soldering and
electronics you may try to replace the LED by another dual type, e.g.
red/green or red/yellow (the white/blue dual LEDs are hard to find and is a
custom made product).

Best wishes
Dieter Doepfer

> -----Ursprüngliche Nachricht-----
> Von: Doepfer_a100@yahoogroups.com [mailto: Doepfer_a100@yahoogroups.com ]
> Gesendet: Mittwoch, 15. Februar 2017 01:14
> An: Doepfer_a100@yahoogroups.com
> Betreff: Re: 1 A-110-4: LED for negative part is OFF most
> of time
>
>
> Dear Dieter,
>
> Thank you very much for your kind reply. Yes, with no signal being fed
> in LFM, the led of my 110-4SE does not light up in white for LFrq
> positioned in the negative range. This is the issue of my unit
> (although the FM sound from it seems fine..) Following your insight,
> my unit is still defective. So I will have to find a way to repair it.
> Thanks again for your support.
>
> Best Regards,
> Ryuichi Tamura
>
> 2017-02-13 21:24 GMT+09:00 yahoo@... 1
> < Doepfer_a100@yahoogroups.com >:
> > 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
> >
> >
> >> -----Urspr�ngliche Nachricht-----
> >> Von: Doepfer_a100@yahoogroups.com [mailto: Doepfer_a100@yahoogroups.com ]
> >> Gesendet: Montag, 13. Februar 2017 09:00
> >> An: Doepfer_a100@yahoogroups.com
> >> Betreff: 1 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 < ry.tamura@... >
> >> ------------------------------------
> >>
> >>
> >> ------------------------------------
> >>
> >> Yahoo Groups Links
> >>
> >>
> >>
> >
> >
> >
> > ------------------------------------
> >
> > ------------------------------------
> >
> >
> > ------------------------------------
> >
> > Yahoo Groups Links
> >
> >
> >
>
>
> ------------------------------------
> Posted by: Ryuichi Tamura < ry.tamura@... >
> ------------------------------------
>
>
> ------------------------------------
>
> Yahoo Groups Links
>
>
>