1 Topic by drifter7508 (edited by drifter7508 2023-03-04 15:53:51)

  • Registered: 2023-03-04
  • Posts: 19

Topic: Fireface 800 randomly not booting up

I just bought a RME Fireface 800. "Mint condition". However it will only start up randomly after flipping the power switch multiple times. After that all works fine.

Time for a recap or a new PSU. I choosed to order a brand new PSU. I installed it without hassle. The same problem as with the old PSU. A-dat lights are lit but no front lights.

Power in the molex connectors housing reads:

Molex cable 1 - 4 pole:
5.7 V
15.7 V
-16.3 V

Molex cable 2 - 2 pole:
50.3 v

Voltage regulators on the main board:
LM1086 CS - 2.5
0 V
2,5 V
5,7 V

LP3892ES
3,3 V
3,3 V
0 V
1,2 V
4,96 V


LM3940IT
5,76 V
0 V
3,3  V

Glitchy power button? Took it out and cleaned the connectors that were kinda corroded. Same problem.
Tried to bridge the connectors without the power button with a "copper clip". No luck.
Tried with a new power switch. No difference.

The unit starts up like using a "lighter", if you flip the switch fast 2-3 times it boots up. Everything works okey after that.

Any hints on what could be wrong or what to look for?

Video links:
https://www.youtube.com/shorts/ox6BihYDyE8

https://www.youtube.com/watch?v=_L3vXztaMj0

  • waedi
  • DAW Mastermind
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  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,173

Re: Fireface 800 randomly not booting up

First thig comes to my mind, broken capacitor, time to do recap..

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2023-03-04
  • Posts: 19

Re: Fireface 800 randomly not booting up

waedi wrote:

First thig comes to my mind, broken capacitor, time to do recap..

No logic behind that. The PSU installed is brand new with new caps.

Any specific capacitor on the main board you are thinking of?

4 Reply by waedi (edited by waedi 2023-03-04 22:59:05)

  • waedi
  • DAW Mastermind
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  • From: Swiss Zürich
  • Registered: 2020-12-08
  • Posts: 4,173

Re: Fireface 800 randomly not booting up

drifter7508 wrote:

Any specific capacitor on the main board you are thinking of?

Every cap on the board

I'm not engineer this was just the first thought, what I would do.
To be on the safe side a send-in for service is not wrong.

M1-Sequoia, Madiface Pro, Digiface USB, Babyface silver and blue
  • Registered: 2023-03-04
  • Posts: 19

Re: Fireface 800 randomly not booting up

I can clearly see that you are not. Appr. you trying to help but the advice you give/guessing have no logic at all in this particular matter. So I hope no poor person takes you up on that, reading this in the future. :-)

  • Registered: 2022-10-08
  • Posts: 62

Re: Fireface 800 randomly not booting up

I checked the vids

I wonder if it may be the on and off switch that is failing

7 Reply by drifter7508 (edited by drifter7508 2023-03-05 10:41:19)

  • Registered: 2023-03-04
  • Posts: 19

Re: Fireface 800 randomly not booting up

novabusrst wrote:

I checked the vids

I wonder if it may be the on and off switch that is failing


I thougt that as well but as I wrote:
"Tried with a new power switch. No difference."


One guy suggested to check this out but that is a bit over my head and no service manuals are available:

"Have you checked the reset line from the psu going to the cpu? Does it pull the line down or up? This would be my first guess...also see if you can find a datasheet of the cpu used to , look at the timing chart. Cycle neds to be completed and i think a line is not acting as it supposed to. Also look at the ic's directly connecte to the cpu, ive seen all kinds of crazyness by bad behaving ic's or transistor that are directly on the cpu lines....was actually looking to get me one of these cards."


Maybe will have to send it in to RME if they still do repairs on these.

  • Registered: 2022-10-08
  • Posts: 62

Re: Fireface 800 randomly not booting up

was the paper tag removed from the screw when you opened it.

all theses units have one stuck on, if it was removed its more likely there was an issue someone tried to repair.

I have two of these units that i use sometimes, if i need more I/O, both paper tags were remove, one unit was recapped but the seller never revealed that, the other unit has a missing firewire 800 port and one blown cap

But the units work fine

Another note the delivery courier threw one of the units at my front door and speed away in his van he threw it so hard the ear on the unit popped out of the box and bent 

but that unit when fired up works perfect .....incredible

I think the best thing is to send it off for service as you said,

9 Reply by drifter7508 (edited by drifter7508 2023-03-05 14:55:32)

  • Registered: 2023-03-04
  • Posts: 19

Re: Fireface 800 randomly not booting up

No warranty stickers or trace of them were to be found. I see no traces of earlier work on the unit either. Some scratch marks on the larger capacitor on the main board though.

Inspected the backside of the board today.
A long botch cable from the larger capacitor 1000uf/50v C1900 going to C922 further away. Guess this is factory?

  • Registered: 2023-03-04
  • Posts: 19

Re: Fireface 800 randomly not booting up

Did a reflow of the molex connectors and LM3940 regulator. No luck.