Scantronic 9448+ power / fuses issue

[MrTan]

So finally after reprogramming my 9448+ with help from this forum, I thought everything was ok.

It seems the problem with my system is rooted deeper.

So here's a sequence of events:

Last week, the 21v AC fuse (F3 - in the middle) popped and the system ran off the back up battery for a day or so.

Replaced that fuse and reprogrammed, all seemed ok.

Monday night, power cut, battery does not kick in. Bell box ringing outside for about 20 mins. Power comes back after an hour, all ok again.

Tuesday, check the battery fuse (F1) - blown. Replace the fuse.

5 minutes later, fuse F3 (21v AC) blows - alarm goes off as the battery hasn't charged.

Fuse F1 for the battery is fine though.

I've replaced the F3 fuse again but removed the battery fuse for now as that 'circuit' seems to cause the problem.

Could it be the battery? it obviously worked fine last week when the fuse went first time.

Could it be the main board?

Or could it be I've put the wrong type of fuse in (I might have put in fast blow instead of slow, not sure)

Finally, I did notice the box was a little warmer than normal after I'd replaced the battery fuse.

Any help appreciated.

 

[joe-90]

Check your 12v power is still 12volts (either the battery leads or 12v and 0v terminals). 9448s have a tendency to cook the voltage regulator when you get a bad battery (short circuit) and the voltage to the battery will go sky high.

 

[MrTan]

Check your 12v power is still 12volts (either the battery leads or 12v and 0v terminals). 9448s have a tendency to cook the voltage regulator when you get a bad battery (short circuit) and the voltage to the battery will go sky high.

Thanks for the reply.

I put a multimeter on the battery connectors this morning after I'd replaced the battery fuse and got an O/L reading.. wasnt sure if the multimeter was dodgy. Battery warning on the multimeter showed after that so figured it was just dodgy.

 

[sparkymarka]

Did you replace the battery or try to charge the old one ?

 

[MrTan]

Did you replace the battery or try to charge the old one ?

I tried to charge the 'old' one.

It had been drained though.

I've ordered a new one in case.

My concern is what caused it in the first place so I know what to fix.

 

[sparkymarka]

Say no more they DONT last for ever, 5 years is the norm... So what's been happening is normal battery makes the transformer overheat and blows transformer fuse, seen it time and time again , just replace battery at £10.. Job done...

 

[MrTan]

Say no more they DONT last for ever, 5 years is the norm... So what's been happening is normal battery makes the transformer overheat and blows transformer fuse, seen it time and time again , just replace battery at £10.. Job done...

Thanks. Hope that's all it is!

Much appreciated.