Can I bypass the INTERNAL fuse in a Ryobi palm sander? - Page 1
Forum section: electronics / repair

author: crunch
author_rank: Newbie
timestamp: September 18, 2019, 08:16:49 am
content: I have a little yellow and Grey Ryobi palm / hand sander which I have used extensively for several years. Yesterday it stopped working.. It just stopped dead...I opened it up and found that the main capacitor had worked itself loose (dry joints)(WTF? it was cheap anyway) and onboard fuse had blown. I re soldered the loose capacitor and jumpered the fuse out to confirm it was the fuse now making it not work. It ran.I haven't been able to find an appropriate tiny glass fuse for 250v at 1.1amps(or thereabouts.. my eyesight is shot these days and I can barely read the markings) with legs on it, so I was just going to put a jumper wire in place of the fuse.BUT: Is this actually a sensible or safe thing to do? Or at least is it not a recklessly insane thing to do? I mean, Theoretically, if it shorts out it will trip the RCD device or just stop again like it did yesterday and the plastic should protect me from the eleventy billion volts and amps keeping the buzzy thing buzzing.I would be keen to get some more experienced input if available.

author: brabus
author_rank: Frequent Contributor
timestamp: September 18, 2019, 08:36:10 am
content: If something fails again (not necessarily a dead short) and the device starts drawing, e.g. 5A,it will catch firewithout any RCD tripping, nor any fuse protecting it from overcurrent.Actually, dead shorts are quite uncommon. The motor may start drawing more current and generating sparks as the brushes wear down, until the rotor locks and the thing starts drawing more current, producing more smoke and eventually flaming.Cool if you want to see some toxic fireworks.So, please do not leave that machine unattended.In such cases, if I cannot find an appropriate fuse, I just end up buying a new machine altogether. Sorry, my health is way more important than a 30$ broken tool.

author: Zucca
author_rank: Unknown
timestamp: September 18, 2019, 08:44:51 am
content: right, if it fails again it will be for the last time, best case.

author: Psi
author_rank: Super Contributor
timestamp: September 18, 2019, 09:46:37 am
content: Replacing it with any other value of fuse is a way better idea than jumping over the fuse.If it had a 1.1A fuse and you can't find them, use a 1.2A, a 1.3A or even 1.4AEven a 1A will probably be fineHell, even a 10A is better than no fuse.Most things that will cause the fuse to blow are very high current, so even a 1.4A will likely blow just as well as a 1.1A

author: TERRA Operative
author_rank: Super Contributor
timestamp: September 18, 2019, 10:12:40 am
content: Why not just solder a bit of wire to the ends of the fuse to make legs?

author: Electro Detective
author_rank: Super Contributor
timestamp: September 18, 2019, 10:44:52 am
content: If you cash out tomorrow, that fuse bypassed palm sander may get handballed to a family member or friend in the future,and cause drama. Insurance companies won't fork out a cracker once they see the bad jerry rigGet a 'close enough' fuse in the sucker asap, there might be a Jaycar near you =or sledge and bin itand hit on Bunnings or Supercheap Auto for a newie and get on with it

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 18, 2019, 12:21:39 pm
content: Quote from: crunch on September 18, 2019, 08:16:49 ama proper rated fuse will always be better if its that easy to get one, if not then slightly over or under rated fuse is better than a non working unit. if its still not feasible or you need to work again asap, jumper wire you used should be as small as the original fuse is, so in case something wrong again, energy needed to explode that jumper will not be much and shrapnels should be minimized to optimum level. i normally strip the black red (not sure what gauge, but its usually used as lamp or speaker wire) wire exposing its many copper wire strand inside and i take just one strand from it. the jumper should also not close or touching the pcb to avoid heat sharing, heat sharing will cause extra energy (higher current) needed to defuse it. if you use thick wire such as from electrical house wiring (3-6 strand inside, about a half mm diameter or so each strand) then be ready for grammy award of explosion shitout. the external plastic enclosure that you lay your hand on may take the impact, but bigger jumper will produce more blob shrapnels giving higher risk to short another circuit, traces or components inside the unit causing chain reaction of explosion shitout. so use the proper size. and better if you can put or fashion aa localized enclosure for it to avoid shrapnels going random, this is the logic behind why a proper fuse have enclosed glass body, so its contained and you can see its blown (i'm bracing myself for hate and death threat impact, you should too) be safe and be know what you are doing, cheers...

author: crunch
author_rank: Newbie
timestamp: September 20, 2019, 02:38:32 am
content: Thanks for the feedback! I have taken it on board... and soldered a 10mm socket spanner across the two terminals.. that should keep the thing running for a while.Kidding!!I'm going to continue to look for an appropriate fuse to put on board the sander and fix it properly.

author: james_s
author_rank: Super Contributor
timestamp: September 20, 2019, 03:01:17 am
content: Any fuse that's close in value should be fine really, certainly better than nothing. While I don't recommend bypassing the fuse, worst case if you do it will probably burn out the motor and trip the circuit breaker if something fails again. Quite a few devices like that have no fuse in the first place, especially older ones. I had an old shop vac in which the bearings seized and it very quickly started spewing copious amounts of stinky smoke then the brushes flared into an arc and vaporized something and it was all over.

author: Nusa
author_rank: Super Contributor
timestamp: September 20, 2019, 03:03:17 am
content: Since you obviously have a soldering iron, another choice is to remove the fuse holder that's there and solder in a pigtail type fuse. Or any other fuse type available that will fit the space. Since its a tool designed to vibrate, gluing your solution down might be required.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: September 20, 2019, 03:08:50 am
content: Agree that protection is somewhere between extremely desirable and mandatory. But nothing says it has to be in the same location. It should be easy to find a fuse holder and fuse to put in the line cord.

author: mikerj
author_rank: Super Contributor
timestamp: September 20, 2019, 11:16:23 am
content: Are you certain the fuse is for over-current protection rather than thermal protection?

author: james_s
author_rank: Super Contributor
timestamp: September 20, 2019, 11:37:39 pm
content: That's an excellent point that briefly occurred to me then I forgot to mention it. Many small motors have a thermal fuse attached to or embedded in the windings.

author: Electro Detective
author_rank: Super Contributor
timestamp: September 21, 2019, 01:41:31 am
content: OP crunch is uploading hi res photos of the entire palm sander as we speak, to sort this mystery fuse thingie out