Fixing a Hartke A35 Bass Amp: 220V Power Source Issue

[jkv6391]

Okay, before I say anything else, the power source here is 220V.
Right. So today I was changing the fuse on my Hartke A35 bass amp. I accidentally used a 5A fuse instead of the 1A one. now it won't work. Am I screwed?

 

[berkeman]

Did you smell smoke? Probably an output transistor smoked... Could it just be a blown speaker fuse or another blown fuse somewhere?

 

[Ouabache]

I concur with Berkeman. If you can open up the box and sniff around the circuit, you may be able to detect a burned transistor. Components that drew too much current may appear discolored.

I found a http://www.samsontech.com/products/relatedDocs/A25-35_ownman_v1s.pdf for your model on the web. It suggests a 1.6A, 3AG slo-blo fuse for the A35 (35Watt model) While you have the box open, look around inside for more fuses. It is possible they may have used internal fuses as an added precaution.

 

[jkv6391]

I just checked the internals; there's nothing that suggests a burned transistor but there is an extra 1A fuse in there. I'll get a few new extra fuses then and see if it works.
Thanks, guys.

 

[Homer Simpson]

There must be some short in the amp to make it blow fuses in the first place. Did the orginal 1A fuse burn out to require replacement?? If everything else was in good working condition, you should be able to bridge the fuse terminals with a nickle and not 'smoke' anything. So there must be some problem like a short.

 

[Ouabache]

I just checked the internals; there's nothing that suggests a burned transistor but there is an extra 1A fuse in there. I'll get a few new extra fuses then and see if it works.
Thanks, guys.

It still quite possible that some components (such as output transistor) may be blown even though they do not look burned. After replacing the fuse, see what happens.. Here are a few possible outcomes: (a) the amplifier works, (b) the amplifier does not work but fuse doesn't burn , (c) the amplifier does not work and fuse continues to blow.
For (a) you've solved your problem, yea! (b) you probably have a burned component (c) you likely have a short to ground.

For (b) and (c) if you're not electronically inclined, bring it someone who is and have them troubleshoot it. I would not use Homer's suggestion about bridging the fuse terminals with a thick conductor. If you do have a short, bridging will cause more harm!

 

[Homer Simpson]

I would not use Homer's suggestion

That sounds like good advice.



(what I meant to point out is that if everything was wired fine it should not be blowing fuses. I have a bad feeling though that it was fault current that blew your 1 amp fuse. That same fault would have been present with the 5 amp fuse, so if you are lucky the parts were robust enough to handle 5 amps and it is the fuse that blew. If you are unlucky, the 5 amp fuse is intact and somthing else opened the circuit. On the sunny side however, you would still have a perfect 5 amp fuse! )