JoeMuc2009 wrote: > It is likely that the display filament power supply circuitry in your > Boom has failed. Many units suffer from this after some years. The > display itself is also wearing out, but if it goes all dark or starts to > fade from the outside edges towards the center, and sometimes recovers > after a few minutes of being powered-off, it's the filament supply with > 95% chance. > A VFD is basically an electron tube, albeit a pretty complex one. In > operation, it needs the filament (the six thin wires close to the front > side of the display) to emit electrons, so it needs to be heated. This > happens at a low voltage and a rather high power. The filament is fed +5 > Volts on the left side and between 2 and 3 Volts on the right, creating > a voltage drop between 2 and 3 volts. The higher this voltage drop is, > the more electrons are emitted (and the brighter the filament wires are > glowing). Besides the filament glowing brighter, the display's pixels > will also become brighter. > In 9 out of 10 cases, the failure is in supply for the the right side of > the filament. Instead of keeping a voltage around 2.5V, it ramps up to > 5.5V so it's even higher than the left side. This stops electron > emission gradually or completely. VFD experts at Noritake (the > manufacturer of the displays used in the Squeezebox range) call this > "filament starvation". > A Boom in operation has some hidden SMD parts behind the display that > get red-hot. I am pretty sure that the failure point can be found > somewhere in that area, however, it is practically impossible to find > suitable replacement components because the SMD markings don't tell > exactly enough what each component is for. > While I could not find a way to repair the root cause yet, I found a > workaround that turned out to work fine for many people who sent me > their Boom for a display replacement. The fix is this: > ... > Cheers, > Joe
Joe, Is there any way to determine if a blank display is the power-supply versus a dead VFD ? One of my Booms has finally died with a blank display (ie. no Logitech display at re-powerup, and doesn't even resurface after some time of power off). Looking at your great and very detailed blog the VFD replacement is beyond my soldering skills - but looking to see if there is a way to diagnose if the power-supply work-around may work for me? Cheers. ------------------------------------------------------------------------ kidhazy's Profile: http://forums.slimdevices.com/member.php?userid=42259 View this thread: http://forums.slimdevices.com/showthread.php?t=106381 _______________________________________________ Boom mailing list [email protected] http://lists.slimdevices.com/mailman/listinfo/boom
