Fuse holders on SCM19A

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Fuse holders on SCM19A

Postby highstream » Wed May 30, 2018 6:08 pm

After three changes of fuses in my SCM19A’s, two aftermarket for SQ, the holders won’t screw in. For the moment, I’ve got contact and the speakers work, but this is an unstable situation. The latest fuses are small, slow-blow, and in size are identical to the ones supplied by ATC. I can’t tell what’s blocking full entry. It’s as if the spring is not getting compressed, or something inside is not allowing the unit to be pulled in by (screwdriver) screwing. I’m told holders going bad is not uncommon for those that change fuses. Any ideas or experience with this? Assuming it’s the holder, though I’m not sure, what type of or size holders should should I be looking for? I’m in the States. Thanks,

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Re: Fuse holders on SCM19A

Postby MattSPL » Wed May 30, 2018 10:28 pm

Hi highstream,

Can you post some pictures?

I’ve changed many fuses in my Hifi and at work as an Electrician. The only time I’ve experienced a fuse holder go on Hifi equipment is the speaker output fuse holder on a Krell integrated amplifier, but this was due to extreme heat from fuse failure.

Those cylindrical fuse holders tend to have to go in a certain way, but usually find their way in.
Have you inserted the fuse fully into the holder?

Feel free to pm me.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > 2 x DIY Dayton Audio UM18-22 Sub

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Re: Fuse holders on SCM19A

Postby highstream » Wed May 30, 2018 10:58 pm

Matt,
Thanks. In an earlier incarnation I was a (steel mill) electrician, so changing fuses is somewhat normal for me. So yes, it's all the way in the holder; beyond that I'm pressing on the spring, which feels very stiff. What I've found are two things since writing. The first is that the latest fuse I've been trying, the Audio Magic Beeswax Ultimate, is because of the way they are put together, a fraction of a mm longer. I sanded it down, but that didn't solve the problem. So I tried the original ATC fuse and it does not screw in either (it's the GB value vs. U.S., but I was looking at fit). The SR Black, which I had in there since receiving the speakers until yesterday, now also doesn't go in all the way. So means the holder is not grabbing the inside. Looking inside the fuse slot, there is a groove on the bottom and presumably the top. I assume the fuse holder's flanges are supposed to grab those, which is what makes for the screw in. It doesn't look like anything is deformed or broken off, but if that's it, the two are not engaging.

The other speaker's fuse holder is also not all the way in, but at the moment it's holding firmly, so I haven't wanted to touch it (that beeswax fuse hasn't been sanded). By the way, the fuses sound great, right out of the box.

I'm not sure how to attach photos, so here are three that may be of help:

https://1drv.ms/u/s!AqsCKHVTj0ydl1c8CJ4-DcDAAIe_ (fuse holder in speaker, but not in all the way - before sanding)

https://1drv.ms/u/s!AqsCKHVTj0ydl1jTkSzVvaSr10bB (rear of speaker stock photo)

https://1drv.ms/u/s!AqsCKHVTj0ydl1lvlIvV_qrhrqDY (fuse holder and beeswax fuse before sanding)
Last edited by highstream on Wed May 30, 2018 11:23 pm, edited 1 time in total.

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Re: Fuse holders on SCM19A

Postby MattSPL » Wed May 30, 2018 11:18 pm

Thanks for the pictures.

Is the spring in the holder or inside the speaker?
If it’s in the holder, have you tried pushing the fuse into the holder manually, rather than by inserting it into the amplifier?
Also, have you tried rotating the holder in a slight twisting left, right, left, right motion once inserted?
Have you tried shining a light into the fuse hole in the amplifier to see if there’s any obstruction?

Have you tried the SR Blue fuses yet? Great upgrade over the black.

Edit: just thinking there, some of those fuse holders have like a metal
Track that the holder slides down as the fuse compresses the spring. If the 2 sides of the track don’t slide at the same time it can cause misalignment. Applying some contact enhancer grease like deoxit might help here.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > 2 x DIY Dayton Audio UM18-22 Sub

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Re: Fuse holders on SCM19A

Postby highstream » Wed May 30, 2018 11:25 pm

I was just adding something to my post when your reply came. Looking inside the fuse slot, there is a groove on the bottom and presumably the top. I assume the fuse holder's flanges are supposed to grab those, which is what makes for the screw in. It doesn't look like anything is deformed or broken off on the holder (see previous photo), but if that's it, the two are not engaging.

I didn't like the SR Blue, either in a Directstream dac or in their P10 regenerator. I've got a comparative review posted on the Audiophile Fuses thread at What's Best forum, I think post 54.

Follow up: tried again and this time the fuse came out with the internal metal "cage" attached to it.

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Re: Fuse holders on SCM19A

Postby MattSPL » Wed May 30, 2018 11:49 pm

The piece of internal ‘cage’ you say came out, does it look broken?

I’ll have a look for your posts on fuses.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > 2 x DIY Dayton Audio UM18-22 Sub

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Re: Fuse holders on SCM19A

Postby highstream » Thu May 31, 2018 12:26 am

I was wrong. The cage came out of the fuse holder and it's not broken. However, my mechanical expertise is not at the level of figuring out exactly how it attached to the spring and sat stably in the holder. So maybe I just need a couple of new fuse holders. Wouldn't that be lovely.

I think it's called a cartridge fuse holder. Not sure of the specs, though.

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Re: Fuse holders on SCM19A

Postby MattSPL » Thu May 31, 2018 9:47 am

Hopefully it’s an easy fix.
I’ll let you know if I come across the right holder, otherwise email ATC and I’m sure they will mail you new holders.

Cheers
Matt
Sony BDP-S790 > Matrix Quattro Dac > Digidesign RM2's with SB Acoustics drivers > 2 x DIY Dayton Audio UM18-22 Sub

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