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July 25, 2017, 06:44:58 pm

Author Topic: New build blowing fuses. [resolved]  (Read 138 times)

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Offline kellanved

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New build blowing fuses. [resolved]
« on: July 15, 2017, 08:50:00 pm »
Working on my first crack, all resistances are exactly what the manual says they are supposed to be, but as soon as the power is connected it blows a fuse, so I have no chance to check anything else. I have checked for shorts, and don't see any. I have also re flowed all of the joints to see if that would help, but with no success.






« Last Edit: July 17, 2017, 09:41:58 am by Caucasian Blackplate »

Offline fullheadofnothing

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Re: New build blowing fuses.
« Reply #1 on: July 16, 2017, 07:50:22 am »
These images are far too small to see any details. Could you please repost using the internal attachment option (i.e. when creating/editing  post, click the orange text below the box that says "Attachment and other options")?
Joshua Harris

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Offline kellanved

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Re: New build blowing fuses.
« Reply #2 on: July 16, 2017, 08:31:17 am »
Sorry about the wrong picture format, here is round two.

Offline fullheadofnothing

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Re: New build blowing fuses.
« Reply #3 on: July 16, 2017, 09:04:53 am »
Thank you for reposting. These are now much more useful.

It appears that you have generally not followed some of the specific instructions about component placement. For instance, your LEDs are installed upside-down, making it impossible to tell at a glance if they are backwards.

Far more troubling is the fact that the 270KΩ resistor appears to be missing. Perhaps you just chose to install it on the other side of the terminal strip, making it again impossible to tell at a glance if it is there or not. If you have left it out entirely, DO NOT turn on your Crack until it is properly installed between terminals 12 and 13. This is a crucial safety feature that is there to drain the capacitors after the amplifier has been turned off. Leaving it off creates dangerous conditions specifically called out in the safety section at the beginning of your manual.

Only the inboard side of your 17-22 terminal strip is visible in your pictures. The UF4007s on that side are installed correctly; you need to verify that the ones on the outboard side are installed correctly and/or post picture showing that they are. If any of these are backwards, or connected (intentionally or not) to wrong terminals, that would cause your fuses to pop.

The error that is most likely causing your problem is the capacitor on that terminal strip. It is supposed to go banded to 20U, unbanded to 21U. Yours is banded to 19U and unbanded to 20U. This needs to be fixed, but if you have unseen diode issues, it will not resolve your problem.
Joshua Harris

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Offline kellanved

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Re: New build blowing fuses.
« Reply #4 on: July 16, 2017, 04:30:40 pm »
Thank you very much, the capacitor was indeed the problem.