I don;t think any suction device will stick to the tolex or tweed or whatever covering you have over the wood. I’ve experienced this with my Mesa cab and a couple of Vietnamese made Marshall cabs. Those were MDF (medium Density Fiberboard) which is even worse than chip board. I took a butter...
You guys got me on this one. I don;t mess with amplifier internals, other than replacing tubes, and maybe adjusting the bias. I find I live longer that way, or at least get electrocuted less…👌🐸