Dearest /diy/kes:
GF screwed up with a piece of second-hand lab equipment (115 V) and plugged it in with a 250 V cord. (Specifically a Forma 3130)
What are the odds that there is some fuse protection and the board isn't fried. She texted me after plugging it in, it running for a few seconds, and the magic smoke came out. I've looked into parts and there should be a 1 amp fuse somewhere.
Pic sorta related
Find where the smoke came out. If it came out of a fuse, then it was protected
Yes, I was just wondering if it's common for these to have protection built-in as such.
>>945172
It's probably bad news. First, fuses don't normally produce smoke when they fail. Second, you can't protect electronics with a fuse; a fuse takes tens or hundreds of milliseconds to fail, a transistor takes a fraction of a millisecond, and an IC will fail even faster.
OTOH, electronics doesn't usually run directly from mains voltage, and a power supply shouldn't propagate mains voltage in the event of a failure, meaning that it shouldn't have fried anything other than the power supply, which is typically one of the easier/cheaper things to fix.
>>945172
Hi OP
fuses don't protect from overvoltage directly, only from overcurrent.
if it was just powering electronics then usually anything recent is smps so they usually just work between 50-250v.
the fact its specifically in two versions there is probably some pump motor or something in there that runs on the mains voltage. if a motor was eating double the voltage it would draw double the current but actually run at four times the rated power.
impossible to tell from your description but usually a fuse won't emit smoke. i mean its not impossible but i doubt there would be enough to notice if it actually did.
>>945243
well if the failure was flashover from breakdown you would expect a breaker or fuse to go
if it ran for a while and melted its because it was running at some multiple of its rated power.
it really depends on whats on the other end, a dc-dc converter shouldn't have cared or really caused the meltdown. is that right? sounds dumb. linear regulator wouldn't have worried if it was within spec, 12v up to 24v wouldn't be overvoltage but would mean a huge increase in heat output for the transformer and regulators.
any smoothing capacitors out of spec voltage wise should be replaced whether apparently working or not.
i would usually say hook it up to a variable supply and see what happens, if it works or not, but even if you have access to one 130va is not an insignificant load, you might find typical variable bench supplies are closer to 50VA
>>945172
Wait wait wait. How the fuck did she manage to plug it into the wrong voltage? Plug ends are designed to prevent that exact thing.
>>945243
A mains transformer often manages to protect whatever is on the low-voltage side in the event of failure. Double-voltage in typically doesn't equate to double-voltage out due to saturation, and even double-voltage won't necessarily fry things if it's brief.
The data sheet gives the connections. There are two primary windings (terminals 1-2 and 5-6) and two secondary windings (7-8 and 11-12). A continuity tester (even a ghetto one, i.e. a battery and a bulb/buzzer/whatever) will tell you if any of the windings have failed.
You'd expect one or both primaries to fail from over-voltage, but if either secondary has failed then you almost certainly have other problems in store, as that indicates that something on the low-voltage side failed short-circuit.
OTOH, even if the secondaries are intact, that doesn't mean for certain that nothing else got damaged, so try to inspect whatever was connected to it for scorch marks or anything else which might suggest more substantial problems.
>>945255
apparently his GF is a fucking moron and OP should just beat her ass
Just out of curiosity, what is your gf using second hand lab equiptment for?
In Canada, a 120v plug/receptacle won't mate with a 240v and so on.
Where does OP live?
>>945255
>>945302
>>945324
The incubator is for legit research as she's a microbiologist. It wasn't completely her fault b.c. the moron who gave it to her had another model of the incubator, Forma 3131 which is exactly the same but has a 220V plug.
For some reason on these instruments all the plugs are detachable and the 115 and 220 are interchangeable in the back.
I told her she should've just been suspicious since we're in ameritard land and 220 isn't all that common.
Fried transformer is attached, I'm an electronics pleb. so I assume on the left that's the primary winding which fried first?
>>945274
I don't have a variable power supply; are there instructions for probing winding terminals to check which one is fucked? Electronics noob like I mentioned.
Also, here's the c.b. which looks OK. Same question as before -- barring scorch marks, is there a simple way to probe with a multimeter and do basic diagnostics?
Thanks bros
>>945370
Follow the wires from the plug and check for continuity.
>>945370
jesus christ.... your GF is one dumb bitch. how the fuck did she become a microbiologist and not know how to properly plug in equipment?
send this hoe back to the kitchen where she belongs...
>>945372
Check for continuity between the power cables after the transformer and where they terminate (e.g. the compressor or heater or whatever).
If everything after the transformer is good (i.e. the resistance is normal and the cables are undamaged), you should be able to buy another transformer off the web for pretty cheap.
Just make sure the ratings match.
sure is lots of edgeposting in here
I almost died laughing at that transformer pic holy fried. Check for continuity with wires checks ohms for loads. I think you may have lucked out change transformer should be good.
Here's a schematic of how the power cords attach.
>>945572
As mentioned the 115/220V cords plug into the device as shown (identically) even though obviously they're wired different at the wall plug end. This is because there is an export model that is exactly the same thing and they wanted to minimize manufacturing cost (probably).
>>945565
Yep she's in the kitchen as I write this
>>945785
>>945567
Will attempt continuity check as mentioned, bought the transformer cause it was fairly cheap. From Thermo's website they wanted 350$ bucks and again Digi Key had it for 43. Da fuck?
Thanks guise, will follow up when I plug the new one in.
>>945793
>Thermo's website they wanted 350$ bucks
All scientific gear is severely overpriced. Not entirely sure why. Incubators generally cost a few grand, while they're not much more than one or more PID controllers controlling temperature and CO2, and maybe humidity.
Kinda suprised Thermo sells parts at all desu, let alone that they have prices on their website for them.
>>945958
>Not entirely sure why
Manufacturing tolerances and certifications (plus general supply and demand)
>>945565
Did you fucking read his post under that picture. The fucking machine has interchangeable plugs
>>945172
Why are you trying to DIY university owned equipment? You're just asking for more trouble. Fill out an incident report and file with the appropriate department.
Guy I work for the electronics department in my uni. And we get this sort of stuff all the time. Most of the gear here is western bloc so ~120. and all the plugs in the labs are standard eastern European 220. So most plugs do get replaced and we use stepdown transformers to run most gear. However some things we don't use as often like analogue plotters and microfilm plotters. But on occasion some old peace of gear will be brought out of moth-balls to be used so we use variacs to wave it up slowly. This is considered good practice when using old electronics. Anyhow every once in a while we get a filthy undergrad who just plugs shit in to the wall and keeps the campus fire department employed. As to how often this happens, well lets just say we have an on campus fire department at this point.
Anyhow most decent lab equipment has fuse protection pre and post transformer. So these are the first to go. If some jackass bridged it due to a lack of proper fuses it pries the primary coil on the transformer. This isn't such a big deal since you can buy transformers for cheap and relatively newer equipment (90+) uses pretty standard stuff. So you can get away with a 20$ repair. If the primary is over volted it shorts out pretty quick and this power on the secondary side drops quick. This somewhat protects the more delicate post transformer circuitry. On occasion it could short both the secondary and primary together. At witch point well your fucked. It will burn our task specific boards and chips and these things cost an arm and a dick.
Really op its down to luck. check the post transformer circuits if nothing looks burned you might be okay. but do swap out the transformer for a new one. The board you posted looks okay if it where to get a lot of voltage those caps would have poped right off the bat
>>945966
Tolerances on stuff like incubators and flowhoods are nothing special at all. Not sure if incubators need heavy certification. Flowhoods definitely need certification, their failure can hurt you at ML2, and badly at ML3.
I gues it's that they have to amortize a lot of development costs over a small market. When I see the diagram at >>945793 though I wonder what they need all of that PCB for.
>>946435
This, depending on how your university works. I'd just send a mail to a guy I know at the electronics support department. He wouldn't need to ask 4chan for advice, let's just say.
To avoid this in future put LARGE voltage labels on equipment and dispose of stray cords or lock them up. Been there, done that.
>>945324
Up and coming supervillainette.
