Rant: Transformer blew on a DSC panel I installed 3 months ago

I had a DSC PC1864 panel go dark on me last Tuesday at a medical office in Toledo. Customer called saying keypad was dead and siren was making a weird hum. Got there and found the transformer output was reading 32V AC instead of 16.5V. That thing was cooking the motherboard slowly. I swapped the transformer and the panel on site, cost me about $200 in parts out of my own pocket. Customer wasn't happy about the 2 hours of downtime either. Turns out the transformer was a cheap no-name brand from a lot I bought on clearance back in January. Anyone else get burned by off-brand transformers or am I the only dummy who tried saving $10?

2 comments

2 Comments

knight.mason11d ago

Read a thread on AlarmTech forum a few months back where a guy tested about a dozen of those cheap import transformers. He found that some of them were putting out voltage under load way higher than what was on the sticker. He also noticed the windings were thinner and the core was smaller, so they ran hotter even when they were working right. That humming siren is a classic sign of a failing transformer dumping too much AC ripple into the DC side of the panel too. I pretty much stick with the Altronix or the Honeywell branded ones now. You might save ten bucks on the part, but you end up losing time and money on a service call like you just did.

murphy.barbara11d ago

Did you check if the siren hum was actually oscillating at 60Hz or closer to 120? A bad transformer can make some weird harmonics that mess with the siren driver chip.