Please help! Fuse blows immediately; can't find issue.

TheCoolDoc · 4695

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Offline TheCoolDoc

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on: January 16, 2015, 02:01:11 PM
I've checked everything everywhere and can't find any issues other than a few terminals in the resistance check.
At terminal 13 is 0.05. If I tap my MM probe on the connection it skyrockets to the correct range (270K and sometimes ridiculously above that), but that is only when I tap it.
I've installed the speedball already and the terminals 1 and 5 don't read anything. I get no reading at all. 2 and 4 are insanely high in the Mega Ohms.

Why is the fuse blowing up all the time. I've also re-soldered each connection to make sure it is a good one, but clearly I haven't done a good enough job.

I can't do the voltage check because the fuse keeps blowing. It's a 1A Slow Blow fuse by the way.

I have provided pictures below, but they might not be of much help because the speedball is in the way.

How/Where to I start troubleshooting? Also, are the tubes supposed to be such a tight fit? I felt like I would break them pushing them all the way in, but I did it nonetheless and they seem snug. They haven't made me snug yet though... :'(

All help is greatly appreciated from this great community. I am not an avid DIY builder (I'm trying to be though) nor do I have expertise in this field. Thank you!



Offline fullheadofnothing

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Reply #1 on: January 16, 2015, 03:13:37 PM
Start by removing the Speedball and installing the resistors. Once you have a working Crack, then you have a baseline to compare the upgrade to.

Joshua Harris

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Offline TheCoolDoc

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Reply #2 on: January 16, 2015, 03:48:58 PM
I disconnected everything from terminal 13 and reconnected and bingo! Things seem good currently, but I've yet to do the voltage check.

Is the 6080 supposed to glow? It's warm, but I don't see any sort of orange glow. The 12AU7 has two orange lights on the top.



Offline TheCoolDoc

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Reply #3 on: January 16, 2015, 04:31:19 PM
Terminals 1, 5, 7, and 9 have 0 Voltage. I don't know if it's a cold solder or because the speedball is attached.

Two lights on the speedball main pcb doesn't turn on and one on the B pcb doesn't. The power tube doesn't have any glow but is hot.

How should I proceed further?



Offline TheCoolDoc

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Reply #4 on: January 16, 2015, 05:31:31 PM
I got a short circuit spark when I voltage checked terminal 3. When I plugged in my headphones I got a shock. Is this a grounding issue? The speedball LED's aren't on anymore.



Offline Strikkflypilot

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Reply #5 on: January 16, 2015, 05:34:43 PM
The fuse blows because something is shorted!
If it didn't, It could have severe consequences. Death. Fire. Etc.
Did You build the crack and speedball without checking if the stock crack without speedball works?
If You did, remove the speedball and restore it to stock and check all resistances before going forward.

Home system:
Sources: Ibasso DX90, Google Chromecast Audio optical out
DAC: Schiit Gumby
Amp: Bottlehead Mainline
http://bottlehead.com/smf/index.php?topic=7463.0
Phones: HD800S

Office:
Sources: Iphone/ Ipod
DAC: Dragonfly Red+Jtrbug
Amp: Crack/Speedball heavily modded
Phones: HD580,HD600 grilles


Offline TheCoolDoc

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Reply #6 on: January 16, 2015, 05:51:19 PM
The fuse blows because something is shorted!
If it didn't, It could have severe consequences. Death. Fire. Etc.
Did You build the crack and speedball without checking if the stock crack without speedball works?
If You did, remove the speedball and restore it to stock and check all resistances before going forward.

Fuse isn't the problem anymore. I just got a short circuit when voltage testing terminal 3. Is that very bad? Will things still possibly be functional? I'm removing the speedball now.



Offline Strikkflypilot

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Reply #7 on: January 16, 2015, 05:54:24 PM
Hard to tell.
Remove the speedball. Make sure everything looks built to stock. Check all solder joints, check if any cable stumps are touching adjacent terminals. Do the resistance check and take it from there.

Home system:
Sources: Ibasso DX90, Google Chromecast Audio optical out
DAC: Schiit Gumby
Amp: Bottlehead Mainline
http://bottlehead.com/smf/index.php?topic=7463.0
Phones: HD800S

Office:
Sources: Iphone/ Ipod
DAC: Dragonfly Red+Jtrbug
Amp: Crack/Speedball heavily modded
Phones: HD580,HD600 grilles


Offline TheCoolDoc

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Reply #8 on: January 16, 2015, 06:24:23 PM
Hard to tell.
Remove the speedball. Make sure everything looks built to stock. Check all solder joints, check if any cable stumps are touching adjacent terminals. Do the resistance check and take it from there.

I'm back to stock and every single resistance tests are perfect except for B6/9 which are giving me 0. I'm going to try to fix the connection, but any ideas?



Offline Strikkflypilot

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Reply #9 on: January 16, 2015, 06:30:55 PM
Got some pictures of the sockets and terminals?

Home system:
Sources: Ibasso DX90, Google Chromecast Audio optical out
DAC: Schiit Gumby
Amp: Bottlehead Mainline
http://bottlehead.com/smf/index.php?topic=7463.0
Phones: HD800S

Office:
Sources: Iphone/ Ipod
DAC: Dragonfly Red+Jtrbug
Amp: Crack/Speedball heavily modded
Phones: HD580,HD600 grilles


Offline TheCoolDoc

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Reply #10 on: January 16, 2015, 06:42:06 PM
Got some pictures of the sockets and terminals?

I just re-soldered it and now every single resistance value on the stock crack is perfect. Do you recommend I do a voltage test now? Sorry for the delay as I am working on it alongside.
Thank you so much for the help btw!



Offline TheCoolDoc

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Reply #11 on: January 16, 2015, 07:05:12 PM
Got some pictures of the sockets and terminals?

I plugged in the amp and the only issue is the power tube 6080 is getting warm but not glowing at all. Maybe I haven't waited long enough, but I think 1 minute is a fair amount. The other tube glows immediately.

Is this supposed to happen? It's still getting very hot so I would think it is functioning. I don't want to do the voltage tests before I know it's alright.



Offline Strikkflypilot

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Reply #12 on: January 16, 2015, 07:10:33 PM
If the Crack is back in stock form, all solder joints look good, and the resistance check went ok...
I don't see why not do the voltage test. You won't find out whats wrong if You don't.
Would like to see another close up of the octal socket solder joints though.

Just remember rubber soles, left hand in back pocket, and don' touch the curcuit with finger.
Good luck!
« Last Edit: January 16, 2015, 07:13:23 PM by Strikkflypilot »

Home system:
Sources: Ibasso DX90, Google Chromecast Audio optical out
DAC: Schiit Gumby
Amp: Bottlehead Mainline
http://bottlehead.com/smf/index.php?topic=7463.0
Phones: HD800S

Office:
Sources: Iphone/ Ipod
DAC: Dragonfly Red+Jtrbug
Amp: Crack/Speedball heavily modded
Phones: HD580,HD600 grilles


Offline TheCoolDoc

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Reply #13 on: January 16, 2015, 07:22:19 PM
If the Crack is back in stock form, all solder joints look good, and the resistance check went ok...
I don't see why not do the voltage test. You won't find out whats wrong if You don't.
Would like to see another close up of the octal socket solder joints though.

Just remember rubber soles, left hand in back pocket, and don' touch the curcuit with finger.
Good luck!

Any word on the 6080 warming up but not glowing?

I've attached some images (not too great quality) of the octal socket.




Offline TheCoolDoc

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Reply #14 on: January 16, 2015, 07:38:56 PM
7, 9, B3, and B6 were 0 in the voltage test. Voltages that are supposed to be 170 were up around 230-245. The rest of them were in the upper end of their range such as 99 out of the recommended 90 or 100.

The 6080 tube not glowing is the only other indication to something being wrong. The resistance tests were flawless.

I'm lost.