Electronics > Repair
Replacing thermal fuse in a fog machine
squinta:
Hello!
I own the same machine.
If it warms up and the command light doesnt go off, then you have a default switch.
If it doesnt wrm up you have a default termal fuse.
Check both for sure.
FlightRisk:
Tough choice whether to revive a dead post or start a new one, but perhaps people still follow this and it is the same issue, different machine. I have an old Gemmy fogging cauldron and it stopped making sounds and blowing fog. But it gets very hot. I tested the pump and power supply, they work fine. I believe it is a thermal switch. I have never seen anything like this before and want to replace it. I shorted the contacts on the board and get sound when I do. If I remove the jumper, it still makes sound. So I *believe* this must be a NC switch that opens at a certain temperature. How can I tell? This has a 50VA power supply (120V 500mA in / 12VAC 50VA (4.2A) out).
Can anyone tell me how these work? Something waits 10 to 15mins or when it gets to a certain temperature and then pumps fog. It must have a timer to pump for a certain time and stop. At first I thought this sensor tells the unit when it is hot enough to fog. Now I think it cuts off at a certain temperature and makes a tiny fan blow. But I have no idea. Can anyone translate the markings? It has a theta symbol and 104 on the outside silicone sleeve (another clue that RT silicone and the flesh colored silicone sleeve must have a max temp) and inside it has VW -1. I see what looks like identical parts available from China, but you need to know NC or NO and what temp. They only go up to 75C on the site I found.
mansaxel:
I've been servicing such machines. What Astrodev writes is pretty much on the spot.
Higher-end machines have a regulator circuit that will control the temperature a bit closer. They'll usually have a temp sensor on the block too, as input to the regulation.
Here, it's much simpler, with the hysteresis of the bi-metal giving a somewhat jagged regulation curve. :-DD
I'm also leaning towards the bi-metal thermostat being welded closed, if the machine does not stay sensibly warm but instead races to glowing.
The absence of smoke can be down to a lot of things. Normally, a membrane pump or similar will push the fluid through the block. Even if you have the best fluid, there's going to be some residue, which will clog the block. Best cleaning method is to safebloc the pump to the mains (assuming it's a mains voltage pump, of course.) and push distilled water through the cold block. When the water's clear and comes out of the block in a long urination-like arc you're good.
Kiukle:
--- Quote from: floobydust on October 11, 2018, 10:23:26 pm ---Most fog machines have fake or no safety approvals.
The FX-800 is claimed to "Intertek ETL Listing" but does not exist in the product certifications database. No fog machines by Chauvet and Sons, Inc. FL USA are in there. It must have been taken by the hurricane. They seem to purchase from HESHAN TONGFANG LIGHTING TECHNOLOGY CO., LTD - Heshan, Guangdong CHINA.
Some fog machines are only basic electrical (grounding, electric shock) tested, and a few for Europe I found tested to the appliance standard IEC 60335-1 which covers fire.
My point is the thermal fuse was never formally tested to provide fire protection in this model.
--- End quote ---
Hi Floobydust, any chance you could look at my new thread? Seems this OP had found his second thermal switch, and I am trying to locate mine, figuring you might be able to help me out
https://www.eevblog.com/forum/repair/need-help-troubleshooting-my-fog-machine/
BILLPOD:
Looks like I have to go shopping, as it seems I'm the only one around here without a fog machine :scared:
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