Guest SjB Posted September 9, 2005 Posted September 9, 2005 My Ademco Microtech Galaxy 16+ fails to arm, and whenever this is attempted message "Unable to set: Power failure" displays in the keypad window. I read elsewhere on this website that a duff backup battery may be the cause, and sure enough checking the original 12v 7ah battery (now four years old) revealed only 10.77 volt DC. I have therefore replaced it with a brand new one that was delivered fully charged, but the alarm system still fails to set and gives the same message. Checking the transformer shows a supply voltage of 246v AC but an output voltage of only 0.4 volt DC so I suspect this is the cause. Please will you be kind enough to advise a suitable replacement that I can buy. The part number written on the existing transformer is TE4-0016 0031 but I can't find a match on the web. Many thanks for your help.
Service Engineer Posted September 9, 2005 Posted September 9, 2005 Looks like you have tested the voltage from the Transformer incorrectly by measuring it on DC, when it should be AC..? Also I really doubt the Transformer has gone. What is the DC voltage supplied to sensors..? Have you checked the output fuses on the PCB.? Is the green LED flashing on the Keypad.? ........................................................ Dave Partridge (Romec Service Engineer)
Guest Guest Posted September 9, 2005 Posted September 9, 2005 Looks like you have tested the voltage from the Transformer incorrectly by measuring it on DC, when it should be AC..? Yes, you are correct; I listened to incorrect advice that the transformer also rectified to DC. In fact the output is 18.60 volt AC. What is the DC voltage supplied to sensors..? Sensor voltage is 13.60 volt DC. Have you checked the output fuses on the PCB.? Yes, thanks. Of the bank of three vertically stacked fuses, I removed the bottom two and successfully checked for continuity. When I removed the top one the external sounder was activated - thus implying that it was intact and I had broken a tamper circuit - so I pushed it back in and the external sounder silenced. Whilst this was happening an LED was flashing on the circuit board. If there are any more fuses - perhaps hidden - please advise! Is the green LED flashing on the Keypad.? Yes, quickly. This was in fact our first indication of trouble; we awoke in the morning to see the LED flashing quickly on the bedroom keypad. The downstairs zones then disarmed successfully but the LED continued to flash and we discovered the problem I have reported. Many thanks for your help.
Guest SjB Posted September 9, 2005 Posted September 9, 2005 Some more info: I have just interrogated the log and in amongst the usual arm and disarm timestamps are a series of entries with "System + fuse / dc fail" and "System - fuse / dc fail" (note the subtle plus and minus symbols). Each 'plus' and 'minus' entry is separated by exactly ten minutes and for each 'plus' entry there is also a corresponding 'minus' entry with the same timestamp. In other words it looks like the system was performing an automated check to a schedule (ten minutes) and kept finding the same fault.
Guest Posted September 9, 2005 Posted September 9, 2005 The LED flashing quickly indicates a DC fault, i.e. battery or aux supply. The aux fuse appears intact as the voltage looks correct and the transformer is functioning normally. The top fuse is the battery fuse and removing that shouldn't sound the external bell unless there is no AC on the board. Did you do these tests with the mains powered off?
Guest Guest Posted September 9, 2005 Posted September 9, 2005 Yes Stuart, I checked the top fuse with the AC off. The reason for this was: 1) Switched off mains at circuit breaker since I didn't at this stage know what I would find inside the control box 2) Removed Galaxy control box cover 3) Silenced warning beep with master code 4) Checked inline supply fuse located in a separate adjacent to the Galaxy box; intact 5) Removed one by one and checked the bottom two internal fuses as described; intact 6) Removed the top internal fuse; alarm sounded; replaced fuse and decided it must be intact to have tripped the circuit on removal What wouuld you suggest I do next, please?
Guest SjB Posted September 9, 2005 Posted September 9, 2005 More info; I have just probed the battery charge/discharge flying leads with the battery disconnected and found only 10.67 volt DC. Knowing that the battery is new and sound, does this confirm indications that there is an aux supply (i.e. battery charging) fault? TVM.
Service Engineer Posted September 9, 2005 Posted September 9, 2005 So all fuses are ok, Voltages are all ok and you have fitted a new battery. Try replacing the control panel lid, and exiting engineer mode in the usual way, after it's checked for tampers the keypad green LED should stop flashing, and if so your problem was the battery and replacing it has cured the fault. System should function ok now..? ........................................................ Dave Partridge (Romec Service Engineer)
Service Engineer Posted September 9, 2005 Posted September 9, 2005 More info; I have just probed the battery charge/discharge flying leads with the battery disconnected and found only 10.67 volt DC. Ignore my above post, looks like we posted at the same time, with the battery not connected you get 10.67 VDC..? What is the AUX DC voltage..? ........................................................ Dave Partridge (Romec Service Engineer)
Guest Guest Posted September 9, 2005 Posted September 9, 2005 To remove guesswork, how shall I check for the Aux voltage please, David? I assumed that I had done this when I probed the battery leads (with the battery disconnected) and only got 10.67 volt across them but perhaps there is somewhere else on the circuit board that I need to measure to get Aux voltage? Many thanks
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