Re: Unusual behaviour DSC-864ULC

["RockyTSquirrel" <gafa_usa@xxxxxxxxxxx>]

"nick markowitz"  wrote in message
news:204607e7-1aed-4b82-a757-435512e2e138@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

On Jun 6, 1:25 am, Frank Kurz <t...@xxxxxxxxxxxxx> wrote:
> OK... This is the second call I've attended on this control.  It's less
> than a year old.  The last time this happened was two months ago and the
> problem had cleared by the time I'd arrived on site.  This time around
> however, the AC light was "off" and the system looked to be running on
> battery.
>
> Here's the troubling part.  Voltage at the AC terminals was 16.9VAC.
> Charging voltage was 13.2VDC.  Yet the panel was displaying an AC fault.
>   There is no visible problem with the board.  I've downloaded the
> software and checked all the relevant locations.  Panel's programmed for
> 60Hz, etc.  This looked to me to be a board level problem.  I
> disconnected the battery (didn't touch the AC) and the system "died".  I
> reconnected the battery and nothing happened.  I then disconnected the
> AC and reconnected it.  Panel comes back on line (displaying the normal
> clock failure trouble).  Reset the clock and the panel clears and
> operates normally.
>
> Since this is the second time the same trouble has appeared, I figured I
> should replace the common control (to be on the safe side).  I swapped
> the sucker out and downloaded the information from the old system to the
> new one.  Everything works.  All zones annunciate.  I'm gonna take the
> old MB and set it up at the office.  Anyone encountered this problem
> before?  I'm thinking this could be a "hold-over" from that batch of bad
> rectifiers but the strange thing is the panel is only seven months old
> and the power section of the board looks to be completely normal.
>
> Oh...  One more thing.  The station received an AC Failure signal with
> the restore when I reconnected power.
>
> Weird.
>
> --
> Frank Kurzwww.firetechs.net

>I'm with you sounds like a board problem Frank if transformer is
>correct etc. you could possibly had a spike or surge damage the board
>with no apparent damage have seen this on several different panels
>where you power down reset and then it seems fine for another few
>months.

check the capacitors around the voltage regulator,  if you see any swelling
or slight cracks,  that tends to show they're going bad,  if they start
changing value it will effect the sensor ckt for the ac loss detection..

Chinese  caps have a bad habit  of going bad early..
((remember all those bad pc board a fee years ago))

RTS