Digitech Studio 400 problem, help desperately needed

Svartmetall

Hi - My trusty Digitech Studio 400 multi-effects unit is producing no sounds and just showing gibberish on the screen (press power and all the buttons light up as normal, and the 'Digitech Studio 400' on the screen is perfectly legible - then it's just jumbled characters at the top and random bits on the main part of the display)...it worked fine the last time I switched it on. These units are long, long discontinued (none on EBay or Reverb) and to say it's been central to the sound I produce would be an understatement - if this has died it will be literally catastrophic for my music work, as so many of the weird sounds I use depend 100% on this unit. If I try a factory reset I will lose all the custom programs I wrote for it all those years ago, which would also be disastrous. I'll never be able to reproduce those sounds without the Studio 400 and the programs I had on it, never. Musically, this is like losing a limb.

Does anyone have any advice? I'm in an absolute panic about this, I'd literally just sat down do some recording too.

EDIT: It's now showing 'Err4'...whatever the hell that means. I've emailed Digitech's support with all the details.

rpr

It might be the battery that's used to retain the memory settings. They last for decades but do go eventually . It's not expensive to replace.

Danny1969

There's quite  a few things that can cause digital processors not to boot properly or not at all. 

The actual LCD screen itself (technically the controller chip on the LCD assembly)   ... some units I've seen,  like the Yamaha Magic stomp won't boot if that goes faulty because it's tested on boot. I fixed one by ordering a £4 replacement from China. 

Bad caps in the digital supply. Over the years all electrolytic caps degrade but the effects are more serious with the ones used to create the digital supply, normally 12V and 5V. If the caps in some parts of the circuit have too high an ESR then the supply will either not start or be seriously unstable. 

You can often see the bad caps bulging upwards on top or leaking out the bottom but if in doubt just change them anyway. I've repaired so many digital devices just by changing a few caps. 

Cables and headers .. sometimes just cleaning and reseating these will cure a fault. 

Bad battery ... but on some devices you may lose the patches if the battery is disconnected. To avoid this it's safer to solder wires from one battery direct to the board near the holder. Then change the battery for a new one, then desolder the other battery. Some units like the Alesis Q20 have soldered batteries on the board so it's even more a pain to do. Other's have a holder like a PC motherboard. 

If you get it working I would try and do a midi dump of your patches or some other method of backing them up before the unit dies completely. 

Svartmetall

Thanks for the replies...Digitech haven't gotten back to me yet; I don't have the electronics expertise to start buggering around inside a unit like this, I mean I can swap out guitar pickups but that's about it really. 

Funkfingers

Superficial Internet searching trawled up mention of a 4700uF 16v capacitor on the PCB that either regulates or stabilises the voltage to keep the digital gubbins happy.

As this cap fatigues, the voltage stability is compromised and things become kinda random. 

I have no idea where this capacitor is located on the PCB or how it is numbered. You shall have to open up the case and look for it.

Hopefully, the cap is close to the mains transformer and far from the ICs.

Svartmetall

This all sounds like it's beyond my electronics expertise, unfortunately; I think I'm going to have to source a good music electronics repair place. 

Digiotech still haven't gotten back to me, which is disappointing.