ht-1 problem

Discussion - HT-1 amplifiers
dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Thu Jul 05, 2012 4:14 pm

Hi, just today i was playing my Blackstar HT-1, unplugged the instrument cable, inserted another. Once i'd done this the sound from the amp went off.

The red on light is still displaying on,
The valves are still glowing,
Ive tried using an alternative power cable,
Tried using an external speaker,
Tried various instruments and cables but can't seem to get any life out of the thing.

Im unsure what to try next so thought i'd try asking you guys for some inspiration to what the problem could be.

dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Thu Jul 05, 2012 6:25 pm

Anything obviously abnormal looking inside I've missed?Image


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majikmojo
Posts: 1329
Joined: Mon Mar 21, 2011 1:00 am
Location: hollywood florida

Thu Jul 05, 2012 7:33 pm

does the instrument input jack on the amp have a good connection?

dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Thu Jul 05, 2012 10:04 pm

Thanks for the idea, Its possibly a little loose, il have a potter with it tomorrow, would of thought there would have at least been some occasional crackling when i put a cable in if it was the jack unless its completely u/s

Before it happened the amp was crackling and popping a little, went to change the instrument cable thinking that was the problem then no sound at all came out.

Cheers.

dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Fri Jul 06, 2012 2:54 pm

Checked the input today, seems fine, besides changing the valves, every other option is more drastic & potentially costly.
The speaker is giving off a gentle hum but not a peep of noise from the knobs or input.

Service@BlackstarAmps
Posts: 30
Joined: Thu Aug 18, 2011 12:00 am
Location: Blackstar HQ Northampton England
Contact:

Fri Jul 06, 2012 3:26 pm

It sounds like the ECC82 may have failed and has taken the PCB mounted (T80ma) fuse with it.
I'd get it in for a repair.

dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Fri Jul 06, 2012 5:09 pm

If i was to pop a multimeter that measured continuity on each end of those little fuses would that be a giveaway of wether it has blown as you would a regular fuse?
Presumably id need to take the fuse out first to do this also. Could be an interesting challenge for me to get the thing back up and running.

superfurry
Posts: 1
Joined: Sat Jul 07, 2012 12:00 am

Sat Jul 07, 2012 1:02 am

The exact same thing happened to mine. It was as the Blackstar guy says the ECC82 failing and taking out the PCB fuse. Pretty poor design imho

I fixed it myself, following the excellent instructions from TheDude in this thread http://blackstaramps.forumotion.com/t10 ... nyone-help

I didn't solder the new fuse to the old prongs though. I took the old fuse out completely and soldered in a PCB micro fuse-holder, then pushed the new fuse into that. It works like a charm and It'll make it easy to replace if it happens again. I should repeat his warning about the possibility of the PCB tracks lifting if you do it this way though.

Hope this helps.


dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Sun Jul 08, 2012 5:14 am

Cheers, this is a massive help, given me a real boost of confidence to crack on and get it sorted. Ive got the parts ordered and shall post my results on here once I've fitted a new fuse & valve.

dawson_25
Posts: 8
Joined: Thu Jul 05, 2012 12:00 am

Fri Jul 27, 2012 10:45 am

Thanks to the help i've had from here ive managed to get the amp back up and running for around £15.

I took a slightly rougher approach to applying the new fuse by just soldering it on top of the prongs of the old fuse, i'l post a photo of the quick fix below.
I also changed the ECC82 valve although i'm not sure there was anything wrong with it.

The T80ma fuse was a little hard to source but after a while of scouring google i found one for around £3 posted.

Image

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