Fuse SMD solder repair in the US?

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TrexXert
Posts: 1
Joined: Sun Dec 17, 2017 8:38 am

Fuse SMD solder repair in the US?

Post by TrexXert »

Hi all,

Loos like I've got a blown fuse in my Kryoflux.

In chatting with support via email, Christian stated that it should be easily replaced with a slow fuse (slow triggering) with 500mAh. Easily done for somebody who can solder SMD.

That said, I don't have the tools or skills to solder SMD.

It's a beefy expense to send the board back to German to have Kryoflux support do it - so I'm wondering if anybody can recommend somebody in the US that can do this for a fee?

Thanks in advance.

brightcaster
Posts: 249
Joined: Fri Nov 08, 2013 10:48 pm

Re: Fuse SMD solder repair in the US?

Post by brightcaster »

Every radio and television technician should be able to do that for a small fee...

David

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: Fuse SMD solder repair in the US?

Post by mr.vince »

Schematics are included with the download, I would recommend replacing it with a self-resetting fuse. We also changed latest boards to use such fuses as mainboards produced over the last couple of years dramatically cranked up USB current (to supply those power-hungry mobile phones attached for charging). It also means that a lot of "cheap" boards don't limit the port to 500 mA, instead some boards deliver 2A or more. Combined with a draining drive, the initial current when attaching it, can blow a fuse. It's still important it's there: Old floppy drives can draw a lot, and you'd be risking to burn your USB ports (a nightmare if this happens to a portable computer where the USB can't be replaced).

The solder job is done in two minutes, I must know, because I have replaced a couple of dozens when we switched to the new fuse type. ;)

drdanj
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Joined: Sat Dec 29, 2012 9:47 pm

Re: Fuse SMD solder repair in the US?

Post by drdanj »

Do you have an example part no. for the new fuse type? I might swap it over in mine when I get a mo...

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mr.vince
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Joined: Tue Oct 05, 2010 5:48 pm

Re: Fuse SMD solder repair in the US?

Post by mr.vince »

We do use 0ZCJ0050FF2G for the most recent batches.

https://www.digikey.de/product-detail/e ... SD&lang=en

Just to clarify: The culprit is not the fuse or the fact that the board _is_ fused on the 5V power rail. It's the change in USB ports and the fact that especially old drives tend do drain a lot of current (as data lines are open collectors, so when not doing / in use they are constantly pulled up to 5V and drained to 0 when active). The fuse is there for a reason - to protect drive and/or board. Exchanging the fuse does not change anything or enhance performance. BUT if the fuse is triggered, changing it for a self resetting fuse is recommended. Please note that resetting fuses do enforce a very slight voltage drop on the 5V rail.

EDIT: self-resetting fuses we use are green, the standard ones are usually just plain white. If the board is aligned horizontally, with USB left and drive connector right, just look at the quartz (the large, horizontal metal cap in the middle of the board). Then look to the left - you will see black brick with "SS14" engraved into the surface. The fuse is the next part to the left. Can post pictures, but it's sunday and there's nothing hooked up for any professional photos atm.

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