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'73-'74 Ampeg V4 - WON'T TURN ON!!!

R

rxbandit79

Feb 20, 2008
32
0
Tempe
www.listentoladylike.com
#1
alright... I'm having some major trouble with my vintage Ampeg V4...

The past few times I have gone to play, my head wouldn't turn on at first. I would pull out the fuse, check it out, everything looks fine, put the fuse back, and it turns on fine.
Turns on fine, plays fine for as long as I keep it on.
This happened about 3 times now.

Tonight I go to turn my amp on for rehearsal and the same thing happens... I go through the usual check list, plugged in, fuse is fine, jiggle the power cable from the back of the head... none of this troubleshooting worked.

someone, anyone, please give me your input. anything you can come up with as a reason or how to fix it without taking it to a shop would be greatly appreciated.

Thanks, Phil
 
#3
Sounds like a bad connection in the fuse holder-- when you pull it out and put it back in, you might be establishing a better connection.

You may be able to remove the fuseholder without cracking the amp. If so, clean the contacts and bend the contact metal back so it will make a better connection. If you can't easily remove it from the outside and are not trained on how to work around tubes-- DO NOT OPEN THE CASE. As you could die (seriously).
 
#6
alright... I'm back... same problem, only worse this time i think...

so I got the amp on last night, awesome... then when I was done playing on it, the power switch wouldn't go down to turn the amp off... finally after working at it, I got it to catch and switch down, however, now the amp won't turn on again.

I've tried fiddling with the fuse holder again and nothing seems to be working. We have a show tomorrow night and I don't think I will be able to get it serviced in time.

any idea on how to get the fuse holder out? I can't seem to get it, but it does jiggle a little.
also, any other ideas on what it could be or how to fix it would also be helpful.

Thanks
 
#9
Its the switch. You described the breaking of a switch perfectly!

This is a fairly easy fix also-- though you will have to open the case. Again- There are things inside the case that will KILL YOU! Don't do this if you don't know what a filter cap (or a capacitor in general) looks like and if you don't know how to bleed a capacitor. Otherwise, you may DIE.


First, buy a replacement switch from an on-line amp parts store. Tell them the model and they will fix you up. These are common parts and won't be very expensive.

Next, open the amp and bleed all the potentials sources of instant DEATH. There should be a nut on the front side of the switch that you can take off. Then you can slide the switch out. Disconnect it from the wires by unsoldering or unscrewing the connection. Make sure you connect the wires to new switch the same as the old one (or your off will be on and vice versa). Replace, fire up, and see if the fuse holder is still good!

If you are not familiar with electronics of your amp's vintage, take it to a pro. Its a quick, easy and cheap fix. While you're at it, have him check the amp for other issues.
 

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