HKC Touch Keypad Keeps Illuminating

[al-yeti]

15 minutes ago, james.wilson said:

I suppose I'd test it by running it on a lead to another location not fixed to the wall

This is why we need you!

[james.wilson]

well at least you think so Al!

[Oisín]

Could anyone with a HKC SW10270 panel tell me what the typical AC voltage is between DC output to earth.  I'm trying to rule out AC interference as I read that this can affect touch screens.  I am getting 36 V AC when measuring between DC supply on the panel and the mains earth.

[james.wilson]

8 hours ago, Oisín said:

Could anyone with a HKC SW10270 panel tell me what the typical AC voltage is between DC output to earth.  I'm trying to rule out AC interference as I read that this can affect touch screens.  I am getting 36 V AC when measuring between DC supply on the panel and the mains earth.

22.3 on mine

[Oisín]

35 minutes ago, james.wilson said:

22.3 on mine

Thank you.  A bit lower than mine.  I don't have any alarm cables running parallel to mains cables, so all the leakage is through the PSU.  Might be a next step for me to try a new PSU if moving the keypad doesn't work.

[james.wilson]

or try removing the ac power (pull fuse) for a bit and see if it continues when on battery only. Also measure your induced ac with the mains off to see the difference between the psu on and off

 

[Oisín]

47 minutes ago, james.wilson said:

or try removing the ac power (pull fuse) for a bit and see if it continues when on battery only. Also measure your induced ac with the mains off to see the difference between the psu on and off

 

Thank you so much.  Looks like the problem has been found.  I removed the mains supply from the panel.  Induced AC dropped from 36.6 V to 1.1 V.  I watched the keypad for 10 minutes and there was no wakeups.  Powered up the AC, and watched the keypad again, 3 wakeups within the first minute.  So it's looking like a faulty PSU that is leaking too much AC.

[james.wilson]

Excellent

[PeterJames]

1 hour ago, Oisín said:

Thank you so much.  Looks like the problem has been found.  I removed the mains supply from the panel.  Induced AC dropped from 36.6 V to 1.1 V.  I watched the keypad for 10 minutes and there was no wakeups.  Powered up the AC, and watched the keypad again, 3 wakeups within the first minute.  So it's looking like a faulty PSU that is leaking too much AC.

You could try an ACT1313 https://www.actmeters.co.uk/alarm-troubleshooting/1313-12v-spike-suppressor

[al-yeti]

1 hour ago, Oisín said:

Thank you so much.  Looks like the problem has been found.  I removed the mains supply from the panel.  Induced AC dropped from 36.6 V to 1.1 V.  I watched the keypad for 10 minutes and there was no wakeups.  Powered up the AC, and watched the keypad again, 3 wakeups within the first minute.  So it's looking like a faulty PSU that is leaking too much AC.

Good job