Melcom st6500 power led flashing

[Richpree]

Melcom st6500 alarm

The green power led has started to flash about every
3seconds its never done if before.

Ive metered continuity on all internal fuses all ok
The back up battery is about 3 months old and giving out 12v

Everything all looks ok inside the control panel

Ive check mains supply all ok

The dc transformer is giving out 18 volts
Does anybody have any ideas on the problem
Or the dc voltage the transformer should be putting out
18 volts seems abit high to me thought they was a 12 volt system

Thanks in advance for any help

 

[sparkymarka]

is it a transformer ( metal block ) or a power supply board ? if its a transformer most give out 15- 22v AC not dc .

 

[Richpree]

Sorry my mistake giving out 18volt ac

 

[sparkymarka]

does it run on battery ok if you pull the mains fuse ?

 

[Richpree]

Yeah all works ok on battery and on the mains just want to sort out the flashing mains led never done it over the last six years strange ive even disconnected all the power mains/batt to try reset but no difference

The mains led is flashing on the two remote keypads front and back door
But the mains led on the panel is on constant

 

[Willy Wombat]

I've been watching this thread for some time, hoping for an answer. And now I have found it myself. The keypad is very sensitive to power supply noise. I have had the the same flashing keypad power LED problem for quite some time. As a result of another fault, I needed to replace the main power supply electrolytic capacitor on the alarm motherboard. Mine was 2200 uF/25V. New problem solved and no more flashing power LED on the keypad.