The bell must be losing 12v positive or have an internal fault, if it were going into tamper or losing 0v the panel should register a bell tamper, if its losing 12v it will just ring on its internal battery.

After reading the post immediately above I would say faulty bell.

connect the cabling back up and take your measurements at the bell itself.

Edited June 2, 200521 yr by breff

Fantastic feedback from this community! Thanks to Dave for the drawing which helped to give me an idea of whats involved. (all following measurements when alarm is unset,wrt 0v, no indication on alm panel that a fault exists) I measured the bell voltage when the bell is sounding and it changed to +6.5v from +6.0. This is between 0v and bell connection. I decided to remove the bell wire to see if the bell still went into alarm mode and it did. STR still measured +13v. TR remained at 0v. The end of the bell wire still measured +6v, though it could not have been this which trigger the alarm. It is looking like a fault in the bell box.

What is SAB an abbreviation for? (strobe and bell?)

Does -ve in the drawing refer to 0v?

many thanks

55632[/snapback]

Re-read my post you should take the measurement from the ext sounder connection AND +12V Connection

Sab means self actuating bell - meaning it has the module with a backup battery connected to it - inside the bellbox

I have taken a look at the external bell box and found that the internal battery has blown itself to pieces! I need to replace the box and could do with some suggestions on where to source a replacement. There are side and back tamper ccts, strobe and siren, internal battery ad 12v supply. Are these units of a standard configuration, so any manufacturer will do as a replacement?

Texecom Odyssey , comes in 4 flavours.

texecom

Available at electrical wholesalers , or online if you look .

Edited June 8, 200521 yr by FASTCAR

Thanks for all your our help on this fault. After changing the bellbox all my troubles are over.