Noob can't work out how to remove head from combo bass cab!

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Noob here,

When I hit low notes, the vibrations within the combo amp are causing a connection issue. The sound cuts in and out rapidly as it is vibrating. I tested the speaker on another system and it seems ok. I am trying to remove the head panel from the cab and can't seem to pull the speaker cables through the cab. I have uploaded photos. Please help!
 

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Trying to remove the head panel? It sounds like you haven't yet freed the amp chassis from the enclosure and the speaker leads remain trapped.

Have you removed any bolts/fixtures which attach the amp chassis to a shelf upon which it sits? Sometimes there are bolts securing the chassis from the top of the enclosure. What about those bolts I see in the second photo?
 
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Trying to remove the head panel? It sounds like you haven't yet freed the amp chassis from the enclosure and the speaker leads remain trapped.

Have you removed any bolts/fixtures which attach the amp chassis to a shelf upon which it sits? Sometimes there are bolts securing the chassis from the top of the enclosure. What about those bolts I see in the second photo?

Hey Galu,

Thanks for your reply.

Yes it seems that the head panel is stuck but I think the only thing holding it in place are the speaker leads. I've removed every screw on top and the head panel is movable and it seems like I might be able to slide it out the back of the chassis if only I could pull through those cables.
 
Look up through the speaker aperture - might the cables be clamped in place inside the speaker compartment?

The last resort would be to snip the speaker leads as far from the amp chassis as possible and rejoin the cables when reassembling the combo.
 
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1) UNPLUG AMP AND LET IT REST 30 MINUTES just in case.

2) Get a long thin blade knife and carefully insert it between chassis and Tolex, front and back, top and bottom, moving it towards the blunt edge.
We don´t want to cut anything, just use it as a feeler to find what´s blocking chassis , be it cabling or some unseen bolt.

So called bred knives are perfect for that.
 
Hello Galu and Fahey,

I ended up getting frustrated and cut the speaker wires and i could get the head out of the cab easier. I don't think I had to cut anything but somehow it made it easier. I want to know how to remove these clips to replace the speaker wires? Also everything seems to be making contact so I'm afraid I'm kind of stuck now in regards to the main issue.
 

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You could drill the clip out with a suitably large drill bit and replace with a simple rubber grommet.

Regarding the main issue, the intermittancy could be down to a worn volume control - did it happen at all settings of the control?

Possibly there is a bad solder joint or a cracked copper track on the printed circuit board. However, access to the rear of the board would require dismantling - starting with the removal of the nuts holding the controls and jacks in place on the fascia.

Hard to give further advice from a distance - perhaps JMF has a suggestion.
 
It is a common strain relief. Note it is two pieces, one is a U-shaped main piece and the other a smaller piece to fit into the U. Squeeze them together with pliers, and it will come out of the hole.

YouTube

Hey Enzo,

Thanks for sharing that, I finally got it undone. The interesting part seems that the end that I could pull out was really inaccessible from inside the chassis (where the speaker sat). It could have been installed the wrong way around but I'm not sure if these strain relief mounts can be removed both ways. Made my life hell either way. Thanks for your help!
 
You could drill the clip out with a suitably large drill bit and replace with a simple rubber grommet.

Regarding the main issue, the intermittancy could be down to a worn volume control - did it happen at all settings of the control?

Possibly there is a bad solder joint or a cracked copper track on the printed circuit board. However, access to the rear of the board would require dismantling - starting with the removal of the nuts holding the controls and jacks in place on the fascia.

Hard to give further advice from a distance - perhaps JMF has a suggestion.

Hey Galu,

Thanks for the advice, I will have to look into it. I don't think it was the volume control but it could be. The louder I turned the amp up, the more vibration and the more rapidly the sound would cut in and out. It wasn't occurring at a particular volume level.
 
...The louder I turned the amp up...the more rapidly the sound would cut in and out.
This could be some kind of thermal or overcurrent protection circuitry kicking in.

Look for (and sniff for) signs of overheating. Check if the heatsink is making proper contact with the output power devices, check if there appears to be the proper smear of thermal grease (or silicone thermal pad) between output device(s) and heatsink.


-Gnobuddy
 
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