Tips to remove stuck chassis from cabinet?

[misterc57]

Any tricks to getting a stuck chassis out of a cabinet?

I have a Yamaha G100 III 1x12 combo. I removed the four chassis screws from the cabinet top. This chassis is not budging a single micron from where it sits.

Thank you!

[g1]

I don't recall this exact model, but are there no screws going through the sides into the chassis?

[drewl]

I've had some tricky ones in the past.

Is there a handle? Sometimes the handle screws also secure the chassis.

Any corner protectors? Sometimes screws hidden underneath.

Use a small flashliight to peak onto any cracks between the chassis and cabinet and look for hidden screws or something binding.

[Jazz P Bass]

According to the Service manual, there are four screws to be removed from the top of the cabinet.

Remove the speaker connection & it should pull straight out the rear.

http://bmamps.com/Schematics/Yamaha/...ice-manual.pdf (Page #3)

[Leo_Gnardo]

Any tricks to getting a stuck chassis out of a cabinet?

I have a Yamaha G100 III 1x12 combo. I removed the four chassis screws from the cabinet top. This chassis is not budging a single micron from where it sits.

Thank you!

Sometimes the chassis "glues itself" to the tolex, after decades of being stuck together, they get that way. Also, sometimes there's a metal foil or screen above the chassis, stuck to the underside of the "roof" of the box. In either case I get out a handy piece of flat brass stock and slide it between chassis and box, prying apart the surfaces. You don't have to use brass, steel will work just fine. I'd avoid aluminum, worried it would bend and crumple under the strain. If your metal flat stock has sharp edges, wear leather gloves for safety, who needs to slice up your hands.

In some cases you have to pry off the grill cloth frame so there will be enough space for the chassis to move out of the box.

[misterc57]

Trying to answer everyone here.

There are no side screws. I did disconnect all wires. It should just slide out.

I think it has glued itself somehow and I will see if I can get some flat edge in there.

I appreciate all the suggestions.

MC

[Mick Bailey]

I have a very thin baker's palette knife that I use. Sometimes it amazes me how tight a chassis can be - so tight it could never have been assembled that way to begin with. Maybe some are snug fit at the start then the cabinet shrinks slightly over the years.

[Jazz P Bass]

As suggested, it may help to pull back the speaker grill. (it's held on at the corners with velcro)

That way you can see in from both sides.

Backlight it as you peer in & you may see what is holding things up.

[drewl]

I also use a putty spreader flat edge to loosen up stuck chassis, also try spraying a small amount deoxit around the cracks to help loosen the seal.

[misterc57]

Chassis is now out

This morning I sprayed a bit of wd-40 where the chassis meets the cab on both the front and back side. Tonight I ran a putty knife in and out and cut it loose. There was some kind of black rubber/felt like tape attached to the chassis that had bonded to the cab.

Thank you for all the suggestions. I never had one this difficult before.

MC

[Enzo]

Welcome to the real world. How many times have we fought side tabs catching on the cab foil, or the chassis edge catching on an upper screen or shield plate. Of just a chassis wedged into the carpet.

[Mick Bailey]

A few weeks ago I ran through a service update for a Fender '94 Twin. The Labor reimbursement in the service note was 3/4 hour - it took that long to get the chassis out. The crazy thing was the thin metal rear-panel sticker was holding it good and tight. Just longer than the chassis so it would spring during assembly but not come out. Like sticking an umbrella up your........

Hot day+Frustration+Swearing.

[Chuck H]

'Something' always seems to be catchy or sticky on half the amps I take apart. Corner protector edges that overlap the chassis clearance, panels or face/rear plates catching on the cut edge of glued Tolex, Shield plates that are wrinkled up from being stapled to the chassis, etc. I've seen the foam stuff around chassis edges too. I hate the foam stuff. It just doesn't last in a hot environment over time and turns into either powder (that is a mess) or gloop (that is a mess). I think this sort of thing gets it into the picture late in the design process once better alternatives are no longer an option and then gets carried on to manufacturing. Why else would anyone use that stuff?

[drewl]

Trying to remove or reduce vibrations is probably why they put that foam tape on the chassis.

Not thinking about us poor saps that have to work on them.

The cheap Tolex that tears, comes loose is the main pain I see alot.

[Jazz P Bass]

'Something' always seems to be catchy or sticky on half the amps I take apart. Corner protector edges that overlap the chassis clearance, panels or face/rear plates catching on the cut edge of glued Tolex,

Ahh, lest we forget the screws underneath the corner protectors.

(Eden Nemesis combo comes to mind)