Customer has a Vodavi XTSc-IP KSU with the V86 MBU. Extension 100 show NO SYNC. The KSU has several boards added. None of the LEDs on the various add on boards light up.

There are 3 LEDs located by the PMU board (a daughter-board the mounts to the MBU). They are also close to the battery.
1. When I power up on the mains (AC) the bottom LED (LD1) comes on faintly and LD2 and LD3 are both not illuminated.
2. When I jumper 24 V DC into the backup power supply input the bottom one (LD1) burns brightly, LD2 burns faintly, and LD3 doesn't illuminate.

I am thinking bad power supply capacitors but am looking for advice. The non-volatile memory battery (1/2 AA lithium) is dead, which I will replace.

Any ideas if which capacitors would be the culprit? Or any other test I should run?

Most likely it's the capacitors. See this thread: https://sundance-communications.com/forum/ubbthreads.php/topics/535196/1

Look for a post by a user named "toogood". He tells you which capacitors are the common culprit.

That one is bulging!!! I will replace it and maybe the rest of those four while I am at it.

Thank You

The too small cap problem, ugly. I had so many XTSc's fail it was almost criminal.

Anybody know what the value of R-349 is? This one is burned, so I can't read the bands. It does test at 218 ohms but as you know, heat can change that.

Resistor.

-Hal

Yes, it is a resistor. But the value isn't silk screened under it and this one is burned a bit in the middle. First band is red (2), second band is violet (7), can't read the next one or two bands to determine if there is a third digit or just the multiplier which I can't read either, tolerance band is gold (5%),

It tests at 217.7 so it is already out of tolerance since the second band is violet.

Does anyone know what the prescribed value of it is?

Does anyone know where I can get a schematic of the MBU? I could get the value of this resistor from that.

Failing that, does anyone know where these boards are rebuilt since Vodavi was acquired by Vertical and now Veritcal has been acquired by somebody else?

IS there any support for these still in existence???