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Old 8th June 2021, 09:26 AM
Dave999 Dave999 is offline
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Join Date: Dec 2007
Location: Twickenham,Middlesex, GB
Posts: 36
Default Re: Depressed Amplifier Chassis - K5881

eminently fixable but in theory you will need to remove most of the internals

you can leave sockets and wireing if they are out of the way of where you need to work just get the txs and the boards out

next find a workshop with hydraulic press

amp face down on rubber mat, use the press with a flat round foot on the plunger. a square one might mark at the corners

press the chassis back to where it should be

any workshop that does automotive repair will have a floor mount or bench mounted press. good for a couple of tonnes

this works on chrome bumpers off 60s/ 70s cars. so should work on your chassis

other tempting option is to try to lever it with a pri-bar or screw driver... this invariable ends in tears as the section by the lever deforms and stretches. The bit you lever against and the bit you are trying to correct both bend
you end up with the middle of the low section too high and the sides of the low section 50% higher than they were but still too low and not right.

the chassis is a bit thick for panel beating and that tends to damage paint.

other option uses a different type of press in reverse and you pull the low section by its mounting holes. again this tends to get the mounting holes back to where they should be but it leaves the rest behind, usually used for getting car door hinge mounts back to where they should be after a crash and before panel work is re done....pressing is best.

home method

flat bench bolted to floor or with something exceedingly heavy on it or held down by timber fence post between it and a window lintel or roof joist Be careful do not jack the roof off you garage.

support amp chasssis from the inside, on specially cut section of kitchen work bench on the cup of a trolley jack
jack the kinked bit into the base of the bench
the flat kitchen bench is usually robust enough to apply pressure over a wide enough area

used his method to straighten the rear of a lambretta that had been stacked vertically on its rear/number plate with many others in a van for its trip from spain or italy into the UK.
had to build a wooden fixture to jack against,bolted to engine mount, moved the rear back again and in line by 2-3 inches, side panels now fit.

proper press is probably best

Dave

Last edited by Dave999; 8th June 2021 at 09:38 AM. Reason: further explanation forgot this isn't an automotive message board :)
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