My HT1R died in 3 months! can anyone help?

Discussion - HT-1 amplifiers
Post Reply
Charvel Guy
Posts: 5
Joined: Mon Jul 04, 2011 12:00 am

Mon Jul 04, 2011 10:05 pm

Long story cut short-
For a few months I was trying to decide on the HT-1 or the Marshall class 5 for late night playing down the hall from my sleeping wife. I decided on the HT1 an the lower wattage. My brother surprized me and gave me the HT1r as a gift. He didnt keep the receipt, The warranty card was in the box when it went to the trash.

3 months later the amp dies. Korg handles the servicing out here in the USA and they wont honor any warranty. I admit, no fault of theirs. Its $100. usd plus parts to fix.

So, now what to do? The ECC82 tube has some serious burn marks internally on one side of the tube, so I bought a pair of replacement tubes that are matched internally. I installed them but there is still no power to the output jack, headphones, or speaker. The output circuit is dead.


I sent a picture of the inside to an amp builder that my band had used in the past. He wont touch it, to much solid state. Below is some of his reply:

First off, there is a lot of solid state in this amp. A bunch of surface-mounted IC's and some transistors, making it something I would not approach for repair (I only do pure tube amps).

I see what appears to be a blown brown capacitor at the lower left corner of the circuit board, white material (or just glue) next to it.

I see a dislocated, possibly burned component near the middle of the board, next to the big IC in the center (to the left of it)

Otherwise, I do not see any internal fuses or other difficulties -

Surface mounted IC's are the worst, this also has surface mounted diodes and resistors. Certainly the way of efficiency and low cost, at the expense of being very hard for the regular person to repair.

I do not see any signs of distress in the power or output trans (they would have leaking wax if they burned out) - the output trans is big for the small output of the 12AU7 - it would be hard to damage it (a 12BY7 with the bias reset would give the amp 50% more power)

I can't help any more with this


Im down to a last resort. So Im here to see if anyone else may have an idea what to do. Here are the details leading up to the amps death...

One night it started popping about 15 minutes after I started playing. I turned it off and let it cool down. Turned it on again, and 15 minutes later it starts popping again. I unplugged the speaker cab, changed guitar cord, still pops. I plugged in headphones and it still pops out of the speaker. So I turned it off for the night. Next night, I pulled the back off to see if there was anything visual (there wasnt). I plugged in and started playing with the back still off. Instead of popping, I heard a hiss that lasted about 2 seconds and the volume went to a whisper. 10 seconds later the amp was dead. I pulled the tubes thinking the hiss was vacuum being released and saw the burnt side of the ECC82. I then bought the tubes that didnt resurrect the amp.

Now Im here, any ideas before I toss the amp in the trash? Getting it fixed is not worth it when a few dollars more gets a new one.

LonePhantom
Posts: 114
Joined: Tue Apr 20, 2010 12:00 am
Location: Canberra, Australia
Contact:

Mon Jul 04, 2011 11:14 pm

Your brother should be able to go back to the store he bought it from, and they can print out the receipt again. I'm sure they'll have in on their records somewhere.

Failing that, just pay the $100 to get it fixed. Don't try and do it yourself. Note it down as a learning experience. ;)

Charvel Guy
Posts: 5
Joined: Mon Jul 04, 2011 12:00 am

Mon Jul 04, 2011 11:38 pm

The Korg guys mentioned that too, and my bro did that, They said they couldnt do it. He said it was more like "dont bother me, I have no time for you". It was the store manager too. So, thats moving on to the next level as well. But its getting to be a bit much of a pain.

And, its $100. + the cost of the parts, that will be marked up as well. I asked how much to just tell me whats wrong? $100.00

I wont fix it, For the slight difference in cost I will buy another one and send in the warranty card, and keep the receipt, and put in the aftermarket tubes from Canada that was mentioned in another thread that makes this amp even better. Of course, that will void the warranty.... :lol:




TheDude
Posts: 13
Joined: Thu Feb 10, 2011 1:00 am
Location: Northamptonshire England

Thu Jul 07, 2011 10:03 pm

This sounds like a bad ECC82 has taken out the HT fuse. The HT fuse is a PCB mounted T80mA type. I'm sure if you replace this & put in a new ECC82 it will be fine.
:D

Charvel Guy
Posts: 5
Joined: Mon Jul 04, 2011 12:00 am

Fri Jul 08, 2011 4:57 am

PCB mounted as in printed circuit board? Thats the best idea i have heard yet. Any idea what it looks like, or where on the board it might be? Im good with a soldering iron, but as far as knowing the differance between a diode and resistor im lost. I havent got a clue what to look for.
Last edited by Charvel Guy on Fri Jul 08, 2011 4:59 am, edited 1 time in total.
Reason: spelling

TheDude
Posts: 13
Joined: Thu Feb 10, 2011 1:00 am
Location: Northamptonshire England

Fri Jul 08, 2011 4:54 pm

Yes, if you look at the circuit board just in front of the 2 red wires it is the small cylindrical black component. It should say F1 next to it on the board and says T80mA/250V on the top. I suggest even if you are good at soldering not to remove the old one but leave the board in and with some long nose pliers pull the top off the fuse. You will see the 2 prongs where the fuse wire was. Solder a new fuse to these prongs but be careful to make sure they don,t short. Pop in a new ECC82 and you should be good to go. Hope this helps. Feel free to ask if you need to know anything else.

Charvel Guy
Posts: 5
Joined: Mon Jul 04, 2011 12:00 am

Fri Jul 08, 2011 11:02 pm

DUDE! YOU ROCK!

I pulled the cap, its blown. I can fix this. You are "THE DUDE"! Thanks so much. I can not express my gratitude and appreciation enough.

So where do you get the fuse wire? I havent looked on the internet yet, and I will. Is there anything that I should or should not buy? Im just going to start with searching for whats on the cap... T80ma/250V + wire fuse and see what pops up.

Again Dude, truly grateful. Thanks to you this little guy will live again.



ADDED LATER ON....

Well, I have found 2 different types of fuses, one is identical to the cylindrical black component, and another that is actually a glass tube as a T80mAL/250V. I assume the "L" is for lag. Here is a link to that one.

http://www.littelfuse.com/products/Fuse ... 8.080.html

I couldnt find actual fuse wire. Is soldering the new component on top of the old component the way to go? If so, Im thinking the glass tube fuse would look cleaner.
Last edited by Charvel Guy on Fri Jul 08, 2011 11:47 pm, edited 1 time in total.
Reason: info added-

TheDude
Posts: 13
Joined: Thu Feb 10, 2011 1:00 am
Location: Northamptonshire England

Sat Jul 09, 2011 9:06 am

That one looks fine. In my opinion it will just be a lot easier to mount it on top as the PCB tracks can easily lift when removing the old fuse leaving nothing to solder the new one to. Doesn't really matter what it looks like as long as it is safe. I think the best thing to do to save hassle in the future would be to find a panel mount fuse holder for a 20mm glass fuse and drill a hole in the back panel of the amp to mount it. You could then change the fuse (if req'd) without any soldering or even having to open amp up. Lots of options available depends how adventurous you want to get.

Charvel Guy
Posts: 5
Joined: Mon Jul 04, 2011 12:00 am

Sat Jul 09, 2011 5:22 pm

I was thinking the same thing. Install a fuse holder. I think Im going to go that direction. There are many discounted "factory refurbished" HT1's. Im betting that the tubes on the production lines are just that, mass produced production items that have a 1 in 1000 scrap rate. When they blow, they take this fuse along with it. I work in a manufacturing environment, I understand the ways of continuous process improvement. If my company was manufacturing these amps, this is something to be addressed. Continually replacing amps under warranty is not profitable. Adding a means of replacing this fuse and offering a "Blackstar Matched Tube Upgrade Kit" for sale would be a nice six sigma project that would move someone up the corporate ladder.

So you mention the word "Safe". Im thinking about cleaning the posts on the old fuse to create a male plug. Then building a female plug to snap on with wires to a fuse holder that can be mounted to the back panel. I know resistance has something to do with circuitry, so would you please suggest a wire gauge that would be appropriate?

Thank you so very much! You rock.

diyrocker
Posts: 1
Joined: Wed Nov 02, 2016 1:21 am

Wed Nov 02, 2016 1:27 am

Hi,
thanks to you all so much for this post.... I too have an HRT1 that "died" when my son was "playing" with it. Swapped the power valve and still dead, so after reading this thread I pulled off the cover on the little black cylindrical fuse... and sure enough the wire was "blown". Ordering up a new fuse-holder and fuse on ebay right now. Just to help anyone else out there.... yes, the cap/cover on the fuse does "pull" off, but it has a thread - so it looks like it would be safer and easier to unscrew the cap off the base of the fuse rather than pull it off as that will put less strain on the mounting pins.
best regards, and thanks again.

Post Reply
  • Information
  • Who is online

    Users browsing this forum: No registered users and 4 guests