Vox Time Machine : pitch oscillates and tap tempo issue

[eh la bas ma]

Hello,

I know this really is a long shot but I thought I could try to find a way to fix this delay.

It's all smd... So I don't have much hopes.

I can't find any schematics...my hopes are shrinking accordingly, but "i still believe"...

There are two problems on my unit : On long delays, the repeats suddenly get weird, the pitch moves like a chorus on extreme settings.It isn't modulating the repeats but rather destroying them in a sea-sick way.

Sometimes restarting the unit fix the problem during several seconds and the bad chorusing effect comes back, on both modern and vintage settings. On short delays, there isn't any problem. The issue appears when Range is set on 1000 ms and Time is set past 10'.

Second issue, not so annoying : the tap tempo works for a short random time, and the unit gets back to the value set by the controls.




I wonder if someone ever fixed these issues on their own unit, I know it isn't the only one presenting these problems :

https://homerecording.com/bbs/threads/vox-time-machine-tap-tempo-fix-n00b-question.323428/

People are talking about a bad batch. I hope there is a way to solve the chorusing problem at least : it prevents me from using long delays.. The tap tempo is very secondary, I only mentioned it because I think both issues can be related .

I remember that once I managed to get the unit to work perfectly for a whole day, by using a different 9V power supply. I tried this again later but it didn't work anymore...Maybe it was something else, like a better impedance, I am not sure. I read in the Manual that it needs 60 mA, as far as i remember I fixed it with something like 500 mA or 1000 mA, does it make any sense ?

https://www.manualslib.com/products/Vox-Time-Machine-7099141.html

What could make this kind of circuit so glitchy ?

Any suggestions would be welcome.