Rail cap symptoms after start up with Clock

[guymusic]

My beloved d8b, after 16 years of faithful service, has finally decided to throw a wobbly, but possibly because I mistreated it?

For the first time ever, I inadvertently had left on my RME Fireface 800, which is clocked to the d8b, and started up the desk. I have read in the Database that symptoms similar to the Rail Cap problem can be exhibited if one does this. Sure enough, that's what I had, or at least partly. After a couple of minutes the faders started moving down on their own, the Vpots flickering, only the Main L/R meter had a regular but slowish rise and fall, no link moving or switching faders with the GUI, so all pretty classic symptoms of Rail Cap failure. It boots up fine, then after about 2 minutes it starts exhibiting the above same symptoms.

I have re-seated the Clock card, cleaned and re-seated all the ribbon cables, and booted up without the three fader boards connected, as recommended as another symptom/fix in the Database. Still the same symptoms as before. Also checked and reconnected the BFC and its big capacitors, and checked the BFC ribbon cable, and reseated the Console connector and cable, as recommended. No difference.

I should mention that my d8b was an early board, however Mackie UK upgraded the CPU to the new Motherboard a couple of years later (2001), so I am assuming that the bad Rail Caps are still there in my early desk. I have ordered up a bag of 50V 0805 0.1uF replacement Rail Caps as recommended by hyaena, which should be coming mid-week, and my technician will replace the 6 recommended by hyaena on the Brain Board. However, I'm not sure if this is the right fix, though I will do it anyway.

Am I going down the correct route? Any more pointers to a subject that has frequently been posted, that I am missing? Clinging on with my fingernails to the desk, and determined not to let it go after all this time!

Thanks in advance,
Guy

[Bruce Graham]

Hey Guy;

I do not know if you are on the correct path or not but it seems to me that it is the right path.

I will be watching for any progress.

Cheers and keep the force.
Bruce

[guymusic]

Thanks for your encouragement Bruce! Was tempted to bail when seeing a dXb200 for £750 here in the UK, with Thomann in Germany selling the cards for £26....but too many headaches I believe!
Will let you know how it goes. Keeping the force!
Cheers
Guy

[Crash]

I might take a dxb if it were free....maybe.

[guymusic]

No joy, I'm sad to report. Had the six suspect Rail Caps replaced on the Brain Board, as per the Database. Still the same issues, V-Pots flickering, EQ, Gates, Compressors and Aux Sends rapidly changing on their own accord, Main L/R meter pulsing, no fader connection with GUI. After some reboots it even asked me for 5.1 Authorization code, and was flaky with seeing the I/O cards. Reinstalled software, ditched Startup file, re-seated and cleaned all connectors again. How disheartening.

Have PM'd "badgeronkeys" who had success with a local technician here in the UK, waiting for his response.

By the way, that dXb went for £677 today at auction!

[anyhorizon]

The six rail caps shown in the database are only an example. They're all over the show and related to nearly every IC on every board. In other words, there are others that should be inspected.

Peter

[guymusic]

Thanks Peter, it's what I feared. "badgeronkeys" has responded with his repairer, so will crack on with it.
Guy

[hyaena]

Unfortunately it´s a fact, that there are more rail caps over the different boards.
But the 6 caps marked in the example are the ones responsible for the mainboard, so I would give it a try, if you ordered the parts already and your technician is waiting with the sodering iron in his hand.
Good luck and get your baby back to work.

I have to admit, that I am going to quit the d8b scene. I have bought a Yamaha DM2000 and under construction.

Manfred.

[hyaena]

In addition to the above said I have the knowledge of my technician:
As far as I could follow the diagnostic progress, he measured the voltages, comparing the input to what was being measurable at the various stages on the boards.
In other words, if there is a loss of voltage on a board, there´s the faulty cap.
Hope, I got it right.

Manfred.

[guymusic]

Thanks for your advice Manfred. Sorry you are quitting, but may I say a big thanks for your invaluable contributions when I was searching the Forum for info. Will get my tech to do as you recommend.
Bis bald!
Guy