Lexicon Larc issues

[frenkonio]

Hi guys,
I need your help for a strange issue related to a Lexicon Larc. I got a M300L, I bought it used and thought, as the Larc was good but dirty, to spray air inside the sliders and then spray also a deoxit solution (I mean directly inside... Already did that with many sliders woth no issues). Problem is that after powering it up if all the sliders stay in the lower position the unit doesn't act strange but when I start moving sliders the unit sometimes goes on reset, but more times it automatically changes the values seen on the screen (I mean going from Predelay to Bass multiplier then Size than reverb time...). It is unusable in this way
So today I unsoldered all the faders, unmounted all, gently cleaned the pcb of every fader with IPA and q tips, cleaned the contact as new with Deoxit and soldered again. Same problem.
You think it is related only to sliders?
I hope you can help me and feel my pain
Every help will be much appreciated. Thanks!

 

[pucho812]

You most likely have another issue related to the arc and not with the sliders. was the unit working before you cleaned it? do have another lard you can swap it with to see if the problem follows the larc or stays with the unit.

 

[frenkonio]

That's what I thought too. Maybe it's not related to the sliders. I only lifted every single buttons to clean them, some of them popped up with the bottom part (the one that contains the contacts) but I simply reinserted them and they all work (when all the sliders are all down at minimum or up at maximum). Tomorrow I will check the buttons again... I don't think it may be related to an IC or a capacitor.. I only sprayed gently with air to eliminate dust.
Yes, it was working before. And I got no other spare Larc to test...

 

[QUEEF BAG]

i don't think it's the faders

try replacing the electrolytics inside the larc.

i had the same issue.

 

[frenkonio]

i don't think it's the faders

try replacing the electrolytics inside the larc.

i had the same issue.

The guy who sold me the unit used it with no issues the day before shipping it to me... You think that only opening and cleaning the Larc have ruined the electrolytics? You had my exact problem ?
Is it necessary to change also the ceramic ones?

 

[frenkonio]

i don't think it's the faders

try replacing the electrolytics inside the larc.

i had the same issue.

Did it today. All caps are exact value from ELNA. Not easy to unsolder some of them (the smallest), the PCB has his age. Now when I power up the unit it loads os, then load the last bank and program but sliders do not work and buttons too. If I press PAGE it goes in Test Mode but you cannot run it. It freezes on TEST MODE - EXIT and only thing to do is to turn off the main unit and turn it on again... I forget to say that I found the Service Manual for the 300L and it says that if the moving of a slider causes the main frame to reset than the U11 IC (it's a CD4515) needs to be replaced. I ordered a new one but I also took out the old one and cleaned contacts. After that the unit had the issues.