Bottlehead Forum

Bottlehead Kits => Kaiju Stereo 300B amp => Topic started by: Why1504 on April 10, 2017, 07:12:56 AM

Title: Blown Fuse
Post by: Why1504 on April 10, 2017, 07:12:56 AM
i just attempted the high voltage test.  The fuse blew.

First, what are the specifications for the fuse? 

Second, how should I proceed?

Thanks!!

Title: Re: Blown Fuse
Post by: Doc B. on April 10, 2017, 07:30:48 AM
First, figure out why the fuse blew. Look over the construction in detail, checking in particular for backwards rectifiers, backwards capacitors and miswired terminals. Make sure everything is correct before you try another fuse and apply power or you could damage the power transformer. Fuse is 1.5A 250VAC 5x20mm.
Title: Re: Blown Fuse
Post by: fullheadofnothing on April 10, 2017, 07:41:59 AM
Dan's answer on the fuse may not be correct. More information is needed, namely:

When was this kit shipped? (this could also be answered by providing the name the kit was ordered under)
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 07:44:43 AM
Early March.
Title: Re: Blown Fuse
Post by: fullheadofnothing on April 10, 2017, 07:46:20 AM
OK. It's a 2 amp slow-blow. The fuse was increased due to some problems people had in the earlier runs, but yours is late enough that it's definitely the 2 amp.
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 08:22:25 AM
Dan's answer on the fuse may not be correct. More information is needed, namely:

When was this kit shipped? (this could also be answered by providing the name the kit was ordered under)

Frank Perkins
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 08:30:17 AM
I have looked everything over. Does anything look out of place?

http://s90.photobucket.com/user/why1504/library/

I am about to head to the airport.  I will pick this back up Friday evening.
Title: Re: Blown Fuse
Post by: fullheadofnothing on April 10, 2017, 08:54:59 AM
p. 40. Last paragraph.
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 09:29:33 AM
p. 40. Last paragraph.

Please look at last photo and tell me where I messed up.

http://s90.photobucket.com/user/why1504/library/
Title: Re: Blown Fuse
Post by: fullheadofnothing on April 10, 2017, 12:24:18 PM
You mounted a UF4007 backwards. It is clearly visible in several of your pictures. I cannot say if it is in the last one or not; that website has repeatedly crashed my browser with all the spam.

Read the last paragraph on page 40 and look at the accompanying picture.
Title: Re: Blown Fuse
Post by: Chris65 on April 10, 2017, 01:13:22 PM
Please look at last photo and tell me where I messed up.

It would be much easier to get assistance if you post photos directly on the forum, rather use those spam laden photo hosting sites!
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 01:33:03 PM
Sorry about photobucket.  I tried to post the pictures from my iPhone and it failed.
Title: Re: Blown Fuse
Post by: Why1504 on April 10, 2017, 02:14:06 PM
You mounted a UF4007 backwards. It is clearly visible in several of your pictures. I cannot say if it is in the last one or not; that website has repeatedly crashed my browser with all the spam.

Read the last paragraph on page 40 and look at the accompanying picture.

I see it now.  I swear I thought the stripes were pointed the same way. Thanks. I can fix that Friday when I get back.
Title: Re: Blown Fuse
Post by: Why1504 on April 14, 2017, 07:11:43 AM
I reversed the UF4007.  Voltages are very low.

10U  39
14U  117
15U  56

They all seemed to be falling the longer it was plugged in.

And, I just discovered the fuse blew again....
Title: Re: Blown Fuse
Post by: Paul Birkeland on April 14, 2017, 08:21:39 AM
Disconnect the UF4007's where they connect to the power transformer, then perform the power transformer test with a fresh fuse.

-PB
Title: Re: Blown Fuse
Post by: Why1504 on April 22, 2017, 04:37:55 AM
Ok. Got back from the last trip late last night. Disconnected the UF4007's from the power transformer. 

Ran the Powerline Voltage test on page 29. Power was at 124VAC

Ran the Power Transformer Secondary test on page 33.  Power was at .8 which I assume means it failed.

Please advise.
Title: Re: Blown Fuse
Post by: Paul Birkeland on April 30, 2017, 03:41:36 PM
Do the low voltage windings still measure properly?
Title: Re: Blown Fuse
Post by: Why1504 on April 30, 2017, 03:57:10 PM
Do the low voltage windings still measure properly?

I am waiting on a replacement transformer that should arrive tomorrow.