• Registered: 2020-12-16
  • Posts: 6

Topic: [Solved] Fireface UFX losing preamp control

Everytime I turn on my UFX the 48v and TRS leds stay on for all four preamps, and while they are on, I can't control the preamps. They still work, sound will go through, but even though Totalmix reflects turning trs or 48v on or off on the interface, it doesn't really change the preamp status (I have tested for this). After the interface has warmed up, the lights go out and the preamps can be controlled again (and jump to whatever config was setup in the panel and totalmix). No apparent issues other than that.

Following advice of users that had the same problem, I have just swapped the power supply for a brand new one. Before doing it, the lights would stay on for much longer and be accompanied by screeches and crackles and all sorts of noise bursts. After the swap, its quiet and tranquil, but the "warm up" period when the preamps are uncontrollable persists.

Can someone tell me what's the problem, or possible causes? I live in Brazil, so sending the unit overseas for repair really is impossible (I would be taxed on the way back, and chances of it getting lost or damaged are too high).

I would really appreciate any responses, as I have been dealing with this for quite some time now.

I have soldering abilities and have soldered on pcbs before. Maybe I can fix it myself?

Thanks a lot in advance!

  • From: Germany
  • Registered: 2007-04-10
  • Posts: 9,691

Re: [Solved] Fireface UFX losing preamp control

Hello,

how old is the unit? This could be an issue of the internal power supply, and this can be replaced, our local distributor could order one...

Regards
Daniel Fuchs
RME

RME Support's Website

3 Reply by fantasmatik (edited by fantasmatik 2021-05-25 16:07:35)

  • Registered: 2020-12-16
  • Posts: 6

Re: [Solved] Fireface UFX losing preamp control

RME Support wrote:

Hello,

how old is the unit? This could be an issue of the internal power supply, and this can be replaced, our local distributor could order one...

Hello Daniel, thank you for your response.

I believe the unit is 10 years old, since on the inside of the top lid theres a sticker sayin "2011".

I also believed it was the internal power supply, from other users accounts, and have ordered a new one from rme-shop and have just replaced it.

But the problem persists. Actually, as I am typing this, I have just started having the same noise bursts as before, although for a shorter duration.

Could it be that the new PSU is also faulty?

Thanks again!

EDIT: just to add that if I turn the unit off after it has "stabilized" and turn it on again after a short time, as in not enough for it to cool down, it turns on just fine, no problems at all, and remains like that as long as it stays on.

4 Reply by MC

  • MC
  • MC
  • Administrator
  • Offline
  • From: Germany/Thailand
  • Registered: 2007-04-06
  • Posts: 25,436

Re: [Solved] Fireface UFX losing preamp control

I am pretty sure the new ps is new and not defective. So the unit needs to be examined in the factory, and then most probably some parts on the main PCB need top be exchanged. No clue what and where, this needs to be investigated.

Regards
Matthias Carstens
RME

MC's Website

  • Registered: 2020-12-16
  • Posts: 6

Re: [Solved] Fireface UFX losing preamp control

MC wrote:

I am pretty sure the new ps is new and not defective. So the unit needs to be examined in the factory, and then most probably some parts on the main PCB need top be exchanged. No clue what and where, this needs to be investigated.

Hi Matthias, thanks for chiming in!

I see. What would be the correct way to do this? Do I have to send it overseas directly, or is there someone in Brazil that would be in charge of that part? It would be great if it could be sent and returned by an official RME affiliate, so I don't risk taxation when the unit is re-entering the country.

Also, would it be possible to have at least a rough estimate on total cost and time for the whole deal? You see, Brazilian currency is terribly devalued right now, and expenses in euros plus taxes can get prohibitely high pretty quick.

Thank you again.

  • Registered: 2020-12-16
  • Posts: 6

Re: [Solved] Fireface UFX losing preamp control

I'd like to update the situation, both for informing the kind gentlemen that have responded to this topic as well as reference for users facing similar problems in the future.

As I explained, I had a problem with my UFX where it would chirp and growl and hiss and crackle, along with preamps being uncontrollable and TRS and 48V LEDs staying lit for at least half an hour every time I turned it on. Researching on the matter I found that it was likely to be a defective internal PSU, which I then ordered and finally got installed.

After swapping the PSU, the original problem changed: when turned on, the aforementioned LEDs would now stay lit and preamps would be uncontrollable, but working (a dynamic mic would pass signal) and noise-free, until the unit "warmed up", when it would then produce a burst of clipping noises, (kind of as if some contact had been made internally) and proceed to be fully functional for as long as it would stay on. On a side note, although the preamps couldn't be controlled, the encoders and the unit's system worked properly, and Totalmix reflected all the changes made in the unit's panel.

This behavior led me to believe something physical was going on:  the connection between the analog (preamps were passing signal) and digital (there was a lack of control) sides of the interface was poor, and would only work properly after things were warm and everything dilated into place.

So I opened it up once more, disconnected all the flat cables, gave them a good cleaning with isopropyl alcohol, reconnected them all and VOILA, the unit is working perfectly again. The one connecting the front MIDI ports was a bit oxidized, but I'm not sure It would be able to cause such havoc. My bet is on the main one connecting the two main boards together (and having such a cable reinforces my thesis, cause it means having a single point of failure between analog and digital environments in the UFX).

I will be watching its behavior closely, and will report it here if something new comes up. If not, it means it was solved!

I would advise any user facing similar problems to give this a try - if your unit is out of warranty and you are used to working with electronics.

Cheers!