Joplin blown fuse

DIY HiFi Forum

Welcome! Need support, you got it. Or share you ideas and experiences.

Hi,

I've got a loaned Joplin amp here and after a few hours use it has blown a fuse. Half a second before it blew, I heard a brief, load hum and may have seen one of the valves flash or brighten out of the corner of my eye.

None of the valves has a short that shows up with a multimeter. Filaments are all fine. I've slipped off the bottom cover and I believe it's a factory build (red paint on all the screw threads) and it looks like a self bias circuit.

Can someone give me a tip on what to check? Cathode bypass caps and coupling caps are the obvious culprits to check. What else should I look at?

Cheers,

Jeff

This post is made possible by the generous support of people like you and our sponsors:

AR Sound

Topic - Joplin blown fuse - jeff mai 02:46:42 10/06/09 (2)

RE: Joplin blown fuse - bcherry 14:45:06 10/06/09 (1)

RE: Joplin blown fuse - jeff mai 12:40:43 10/08/09 (0)

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.