have you metered the bell output to check its switching?

dont know the 9448 but is the output programmable ie is it set to bell. But wither way id meter it to see if its going 0v.

The output isn't programmable.. It's not on the programmeable options list and I can't find any other mention that it is in the manual.

What do I meter between to check that the output is going negative.

Phil.

The output isn't programmable.. It's not on the programmeable options list and I can't find any other mention that it is in the manual.

What do I meter between to check that the output is going negative.

Phil.

The bell test function from the panel also triggers the Ext Bell.

Meter across 12v & Bell, also meter across 12v & STR, both when panel in alarm (mains off for safety, someone else might have to hold tamper spring in.)

If you have an on board keypad & 9427 remote keypad connected, I would suggest disconnecting fully the 9427 and try triggering panel without it. Also loop out all zones & tampers (excl bell unit) and remove any power to PIR's etc.

I know you have tried before, but double check 2ply removed (64 ent, 1 ent).

Meter across 12v & Bell, also meter across 12v & STR, both when panel in alarm (mains off for safety, someone else might have to hold tamper spring in.)

If you have an on board keypad & 9427 remote keypad connected, I would suggest disconnecting fully the 9427 and try triggering panel without it. Also loop out all zones & tampers (excl bell unit) and remove any power to PIR's etc.

I know you have tried before, but double check 2ply removed (64 ent, 1 ent).

I'm getting a reading of 1.63 volts across both the tests.

Assuming mains off. What voltage on battery terminals?

Assuming mains off. What voltage on battery terminals?

12.85v

Sorry about keep quoting you but when I select the "Reply" button the site keeps giving me the "Quote"

Phil.

use the larger "add reply" button a little further down the screen

Thanks for that

Well, if no 2ply selected, no remote keypad connected, no PIR's etc connected to AUX and all cct's looped out so just panel & bellbox wired, with all fuses ok, and bell & strobe work if you put 0v direct on bell & STR terminals, I'd say faulty panel.

Given all the test you have carried out it sounds like a panel fault to me. (or a blown fuse)

When the bell should be sounding either through the bell test or actaully triggering the alarm you should have roughly 12 volts between bell and positive supply.

Do 9448s still have a link to select between SAB and SCB?

If so make sure it's set to SAB although I suspect if it wasn't your sounder would be sounding now!

Note. Assuming that the panel could be faulty... the suppliers have exchanged it........ but the problem is still the same.

I'd say faulty panel.

2 in a row!

No ones that unlucky surely?