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AMPEG Micro VR head_ No sound after removing its cooler

A

Ampeghead

Jun 20, 2019
2
0
#1
My Ampeg Micro VR bass amp, complete w/ its original cabinet, was brand new when I tried to get rid of the noisy cooler.
I simply removed the cooler from the circuit by disconnecting its mini switch. But, as I turned the amp on, I heard a loud pop, and that was all, no more sound came from it.
I tested the cabinet on a different amp head and it sounded perfect, no damage. I also tested the "Phones" output, located at Micro VR's front panel, and it was also working fine. But no sound from the SPKRS output at the rear panel.
I tried to put the cooler back hoping that it would help but it just didn't.
What could have happened?

Thanks in advance for any help.

.
 
#2
You'd have been better off disconnecting the fan itself instead of its switch. Doesn't it just attach to the PC board with a molex plug? I have one but the fan noise never bothers me so I never checked it out, but I thought that's usually how they do it.
 
#5
The headphone out is before the power amp. Since that is working, it appears that the problem is in the next stage which is the power amp.

Look for any obvious signs of damage and show that to your tech. Unfortunately, there isn’t a simple solution.
 
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#6
I did not modify the amp. The noise from the fan was really disturbing and I simply could not concentrate on my playing. There are several people on the web complaining about Micro VR's noisy cooler/fan. Yes, there is a Molex plug on it and I pulled it out from its socket.
I will look after a technician, a very hard job here because I live outside the US.
Regards.
 
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#7
Unplugging the fan is modifying the amp. The manufacturer put a fan in there for a reason, perhaps you discovered that very reason?

Some fan circuits detect the fan load and/or RPM and will not operate with the fan disconnected, a form of protection against what might happen in the field.
 
#8
Ampeghead said:
Yes, there is a Molex plug on it and I pulled it out from its socket.
Click to expand...

Poor idea. You never know what it a “must have” part for an electronic device unless you designed it. I guess now you know the fan is important.

I had a Fender Frontman 100 guitar amp a few years back that I’d decided to change the power indicator LED on. Well, turns out on a Frontman 100 the damn power LED indicator is a vital part for signal flow, put in the new LED and there was nothing but dead silence. Put the old one back in and I got lucky; it worked.

You don’t know what you don’t know, but you can rule out courses of action based on not knowing certain things. I don’t work on cars because I don’t understand how they work. At all. I’ve refinished a couple, because paint is something I understand, but I’m not going to replace a water pump because I have no idea of what it looks like and a minimal idea of what it does. Similarly, I wouldn’t go yanking a fan out on an electronic device because, aside from “keeping something cool” I don’t know what it does.
 
#9
Believe me, wherever you are in the world, if you walk into an Authorized Ampeg Service shop (and this is a business authorized by Ampeg and/or your distributor to do warranty work in your country), and tell them what you did, unless they are being very charitable in what they will cover, you have, indeed, 'modified your amp' and it won't be repaired under warranty.

I'm sorry this went wrong for you, but I can think of no manufacturer of most any product that will cover something that was working as intended . . . . . until you 'fixed' it and the product failed.
 
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