Scantronics 9954 expander problem

[washerman]

Hi all,
I have installed an expander unit 9954 onto my scantronics 9751 alarm unit which has been working fine for months however it has started alarming a few times and the message on the man unit reads as follows :
"EXPANDER MISSING".

I have been resetting the unit which the opperates again for a few days but then we start all over again.

Cable looks good between expander and main unit...Help please.

 

[Alarm]

Check all the connections.
Check voltages at the expander. ( What is attached to it)
Maybe double up the power cores.

 

[9651]

Was there not a recall on 9751 for this, or was it keypads?

 

[Alarm]

Just checked Cooper archives, there was a issue with power next to the data lines they said use the AUX power for the peripherals.

 

[EightyTwo]

As always, check for induced AC (check for AC between +12, 0V and Earth - all three ways) and fit an ACT1313 spike supressor. This usually works for me...

You could also check that the cable between the panel and the HWX (and the keypad) isn't running too close to power or data cables.