Hakko hasn't heard of fuse holders? - Page 1
Forum section: electronics / general

author: lpc32
author_rank: Frequent Contributor
timestamp: July 07, 2015, 06:13:15 pm
content: What's the idea of axial fuses anyway?And by the way, how come it's 2A for 125V rated, but only 0.63A for 250V?

author: Neilm
author_rank: Super Contributor
timestamp: July 07, 2015, 06:26:35 pm
content: I have seen fuses directly soldered to the PCB before now, but that was due to the size of the fuse as it was for 10A operation and needed a very low resistance. Soldering the fuse in reduced the fuse resistance and lowered the fuse so it would fit in the space envelope.

author: electr_peter
author_rank: Unknown
timestamp: July 07, 2015, 06:52:45 pm
content: Most likely cause is space saving. Adding fuse holder adds width, height, depth, mass, obstructions, holes. Also, manufacturer should take into account a need to be easily replace fuse. Requirements for extra space and complexity add up fast.

author: lpc32
author_rank: Frequent Contributor
timestamp: July 07, 2015, 06:54:12 pm
content: I don't think space or resistance concerns are an issue in the FX-888D and similar?

author: SeanB
author_rank: Super Contributor
timestamp: July 07, 2015, 07:06:40 pm
content: Fuse holder is 2c extra, an as you already have a manual soldering operation on the board the lack of holder is no extra time on clipping it into the 2c holder.Power rating difference depending on current is standard, though you mostly will get 2A on 125V and 1A on 250V, they must have measured and found the cheaper in volume because it is not a standard integer amp value fuse would survive the switch on surge at least 20 times or at least the initial factory "turn it on, did it blow up, no so ship it" test.

author: nanofrog
author_rank: Super Contributor
timestamp: July 07, 2015, 10:33:52 pm
content: Quote from: lpc32 on July 07, 2015, 06:54:12 pmDo keep in mind, it's built to meet a low price point, so the BOM is very tight.

author: lpc32
author_rank: Frequent Contributor
timestamp: July 08, 2015, 08:36:36 am
content: If price is the reason, color me disappointed. It's not supposed to be a Chinese product built as cheap as possible, and it doesn't cost like one.SeanB: What, amp rating with a decimal point vs whole number makes a difference?

author: lpc32
author_rank: Frequent Contributor
timestamp: July 08, 2015, 08:40:17 am
content: Yeah, it's original. They call this fuse boardB3722. No fuse holder, and stupidly mounted on top of the transformer by soldered connections, to make the fuse difficult to replace.

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: July 09, 2015, 02:56:08 am
content: I suppose, unlike a DMM, the fuse really shouldn't be blowing in the soldering station. If the fuse blows, something else has gone seriously wrong and you'd probably be repairing that anyway.

author: continuo
author_rank: Frequent Contributor
timestamp: July 09, 2015, 08:20:09 am
content: Yeah, if you connect your poor 110V Hakko to 230V mains, such things may happenhttps://www.eevblog.com/forum/repair/hakko-fx-888d-120v-connected-to-230v/

author: SeanB
author_rank: Super Contributor
timestamp: July 11, 2015, 09:23:19 am
content: Quote from: lpc32 on July 08, 2015, 08:36:36 amThinner fuse wire, so has to be passed through another diamond die that is not used often in production, so more expensive. 1A wire is almost double the area of a 500mA wire, which can be drawn in a single pass from the 1A wire with the right beeswax lubricant, and which is a popular wire so large volumes. 630mA is in between so the extra step of the 500mA wire but not as common a fuse. they must have gotten a batch from a manufacturer somewhere on the market cheap, and as they found a 500mA fuse blows at switch on every so often, and a 1A one does not, they tried the 630ma one and found it did the same as the 1a, so they saved money off buying the common 1a fuse new.

author: Psi
author_rank: Super Contributor
timestamp: July 11, 2015, 10:14:26 am
content: Quote from: GoneTomorrow on July 09, 2015, 02:56:08 amthe fuse in my 888 blew and i had to unsolder and replace it

author: lpc32
author_rank: Frequent Contributor
timestamp: July 12, 2015, 03:51:58 pm
content: Quote from: Psi on July 11, 2015, 10:14:26 amWhat did you replace it with?The one I removed (NSF FCT from Nippon Seisen Cable) appears to be amedium/semi time-lag. I can't find any readily available medium speed fuses, just quick/fast, but I'm not sure if the general speed ratings are that meaningful. Depending on the overcurrent range you look at some "fast" fuses are slower than this FCT "medium" fuse, though maybe not in higher currents.Quote from: SeanB on July 11, 2015, 09:23:19 amSo that would make it more expensive rather than cheaper, no? If by chance they found some cheaper stock for 0.63A you wouldn't expect it to become the default type, as indicated on the fuse PCB. But for a 70W station 230V/0.63A is actually closer than 120V/2A, so maybe the 2A is the unexpected one.BTW, any idea what's that small piece of rubber foam below the PCB for?

author: djQUAN
author_rank: Frequent Contributor
timestamp: July 12, 2015, 04:05:49 pm
content: Quote from: continuo on July 09, 2015, 08:20:09 amYup. Had that happen to mine. (The first 888 without the "D") After doing myLED modand decided to test it out, I accidentally plugged it into the 240V outlet on the workbench. Replaced fuse and it worked again. Still using it many years later.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: July 12, 2015, 04:28:08 pm
content: Hi,The real reason is to make you buy another soldering iron, because you need a working one to change the fuse in the broken one.After all they sell soldering irons..Regards,Jay_Diddy_B

author: Psi
author_rank: Super Contributor
timestamp: July 13, 2015, 06:10:53 am
content: Quote from: lpc32 on July 12, 2015, 03:51:58 pmWhatever I hadI think i pulled the end caps off and pushed them onto the new fuse

author: Psi
author_rank: Super Contributor
timestamp: July 13, 2015, 06:12:06 am
content: Quote from: Jay_Diddy_B on July 12, 2015, 04:28:08 pmYou know what, I think your right, I think it was done as a joke

author: lpc32
author_rank: Frequent Contributor
timestamp: July 13, 2015, 09:17:32 am
content: Quote from: Psi on July 13, 2015, 06:10:53 amI guess you're not planning on tripping the new fuse.Quote from: Jay_Diddy_B on July 12, 2015, 04:28:08 pmWell, they failed.

author: amyk
author_rank: Super Contributor
timestamp: July 13, 2015, 10:15:30 am
content: Even the cheap Chinese hot air stations have the fuse in a holder (although not always connected to the right side of the mains)...

author: lewis
author_rank: Frequent Contributor
timestamp: July 13, 2015, 10:59:12 am
content: Here's a little gem from a class D power amplifier:

author: Psi
author_rank: Super Contributor
timestamp: July 13, 2015, 10:59:14 am
content: whats why i think it was done deliberately as a joke

author: lpc32
author_rank: Frequent Contributor
timestamp: July 13, 2015, 08:35:21 pm
content: Quote from: lewis on July 13, 2015, 10:59:12 amArt?

author: GoneTomorrow
author_rank: Regular Contributor
timestamp: July 13, 2015, 10:16:24 pm
content: Quote from: Psi on July 11, 2015, 10:14:26 amThe question would be why is blew. I'm sure Hakko did the maths to ensure that the fuse is specced to handle all normal conditions, something must have gone funny. I suppose a large voltage spike might cause a blown fuse. I'd be worried about the poor transformers primary winding in that case though.

author: lowimpedance
author_rank: Super Contributor
timestamp: July 13, 2015, 11:22:37 pm
content: Quote from: SeanB on July 11, 2015, 09:23:19 amInterestingly the 630mA is the most common value I have found in domestic electronics of the dvd / video and similar for 240V mains at least.