ht-1 problem

Discussion - HT-1 amplifiers
FranP
Posts: 12
Joined: Sun Nov 06, 2011 1:00 am

Sat Sep 15, 2012 2:29 pm


Hi,


My HT1R had the same problem and thanks to you guys I sorted it out !!

I just wired the two sides of the fuse ( bypassed) so It works but it is not protected (no fuse ) ....
....my worry is what is the risk without fuse ???.
What can create an over tension ??

Thanks !![img][/img][img][/img]

ULTRAMEGA
Posts: 4
Joined: Wed Feb 13, 2013 8:56 pm

Fri Mar 08, 2013 6:11 pm

Thank you very much for the info!

I had the same problem. I don't think I would have figured out this was a fuse, and that it had blown, for a long long time on my own.

The fuse on the board wasn't easy to find (to buy that is), not super cheap at about £3.50ea. or more + delivery, and would be an ar5e to replace ... and if it blew again?

Instead of replacing like for like, I removed the top of the fuse on the circuit board and soldered a 20mm glass fuse holder to it. Cable tied to the existing cables, it's nice and secure.

I bought a pack of ten equivalent 20mm glass fuses for about £2.50, and it's a doddle to replace them should it happen again. In fact, I tested with the old valves still in, and it blew again. Bad valve proved. New fuse & swapped valve and now happily playing again for less than a fiver (not including the valve).

I did consider drilling the chassis to make changing the fuse possible without opening it up but, in the end, I decided against it.

Thanks for saving me taking this for repair, which I'm sure would have relieved me of much money, and it was quite satisfying to fix it myself.
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bluesoverdrive
Posts: 8
Joined: Wed Jun 05, 2013 12:25 pm
Location: Brazil

Wed Jun 05, 2013 2:05 pm

Hi there Dawnson_25!

I am looking for the fuse online, find this one: http://www.ebay.com/itm/EFT-T-80mA-Time ... 337c4c414a

My amp is 120V, does it matter?

Is it the right one? If not where can I find it?

Thanks

Stu1111
Posts: 3
Joined: Wed Aug 06, 2014 2:25 am
Location: Scotland

Wed Aug 06, 2014 2:33 am

Hi folks, I'm wondering if this problem is the same for what's happening to a Blackstar HT1R I have. When I turn it on it plays fine with no popping noises or cutting out for about 5-10 mins every time. Then it starts popping and cutting out making crackling/popping noises until my guitar signal is barely audible, this only happens through the speaker but when I'm connected to the emulated output/headphones socket the sound is unaffected through headphones except the speaker still does the same popping/crackling noises as if I was playing through the speaker, I hope someone can point me in the right direction to fix this that would be great, I've tried swapping valves and that's definitely not the problem here. The amp is only around 6 months old.

ULTRAMEGA
Posts: 4
Joined: Wed Feb 13, 2013 8:56 pm

Wed Aug 06, 2014 8:08 am

I would keep a fuse in there. I think the same failure without the fuse will burn out something expensive. Maybe the power xformer or something else. I wouldn't like to find out the hard way

Stu1111
Posts: 3
Joined: Wed Aug 06, 2014 2:25 am
Location: Scotland

Thu Aug 07, 2014 1:10 am

Ah ok, I'll just call Blackstar for this problem then since it maybe isn't a fuse problem I don't want to go ahead and replace it.

ULTRAMEGA
Posts: 4
Joined: Wed Feb 13, 2013 8:56 pm

Thu Aug 07, 2014 7:05 pm

Stu1111 wrote:Ah ok, I'll just call Blackstar for this problem then since it maybe isn't a fuse problem I don't want to go ahead and replace it.

I had a few problems posting from my phone. The post I think you're replying to is not the one I meant in response to you ... same result, though.

for the sake of clarity, what I tried to post (but lost), in response to your initial post, was that I don't think that your problem could be caused by the fuse (although I can't say anything with 100% certainty as I've seen too many strange things in my life) ...

but, if the fuse were blown, you'd get no sound from the speaker at all from power on. I'm guessing the same from headphones, although I don't remember if I tested that when mine was blown. I have a suspicion I would have ... and I guess heard nothing.

This fuse blows when the valve fails/is faulty and, In my inexpert understanding, ... draws too much current from the power transformer

Stu1111
Posts: 3
Joined: Wed Aug 06, 2014 2:25 am
Location: Scotland

Fri Aug 08, 2014 4:57 pm

Oh ok, thanks for clearing that up. Yea amps do strange things at times. Do you know if this a problem for a lot of HT1R's or is it rare? If not its a poor design. I'll just have to get it to an amp tech cause I've no idea what else to do. Cheers.

ULTRAMEGA
Posts: 4
Joined: Wed Feb 13, 2013 8:56 pm

Fri Aug 08, 2014 6:53 pm

Stu1111 wrote:Oh ok, thanks for clearing that up. Yea amps do strange things at times. Do you know if this a problem for a lot of HT1R's or is it rare? If not its a poor design. I'll just have to get it to an amp tech cause I've no idea what else to do. Cheers.
I think it's probably quite rare so, maybe, forgivable. Perhaps the tube/valve has to fail in a certain way to for it to blow that fuse.

It's repeatable. Since I had 10 fuses, I tried a fresh fuse with the same valve, and it immediately blew again. Changed the valve and another fuse; no problems since.

I guess there could be a reluctance to mount something at the back that could, potentially, expose someone to mains voltage (or worse), but I would have thought it would be possible to make it safe.

Anyway, a pretty easy fix for the mildly electronically adventurous.
Your problem sounds like it will be a bit more involved to fault find.
Sorry I can't offer anything on that score, but perhaps someone else on the forum can.

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