Bigguy2017

Similar experiences here; barrel jacks just don't last. Genuine Switchcraft seem the best of the bunch. Pure Tone do one BUT I don't think it's multi-contact like their fancy open jacks... One thing I have noticed is that the jack's rotational position relative to the pull on the cable makes a difference - a pull in one direction causes signal loss but the other three cardinal directions do not. If you're getting signal drops from cable wiggles try rotating the socket 180 degrees.

Fender Rumble 200 block diagram shows a second order (12dB/octave) HPF. No indication of cut-off frequency.

First try putting a jack cable between effects send and return - it's common for the switched jacks to play up when rarely used. Then try plugging effects out into another amp - this will show if the preamp is working. Also plug a line level signal into the effects return - this will show if the power amp is working. Power down, isolate and do a thorough visual inspection - replug any connectors, look and smell for burnt components and swollen caps.

Or just bolt it to a 2U rack shelf.

Hotter pickups = more wire = louder + less bright (or hotter pickups = stronger magnets = louder)

Yes, A to D spacing is very wide - looks like the string positions on the saddles

My ballpark setup is a 10p piece on the 12th fret just drags on the string (2mm). The Stingray is a bit lower - 1.75mm.

The Quiklok BS317 Amp Stand is solid, inexpensive and works for me... £39.00 + P+P https://www.andertons.co.uk/guitar-dept/electric-guitar-accessories/electric-guitar-hangers-stands/quiklok-bs317-amp-stand

Try Matty Dread on eBay - he's in Ireland and made me some replacement string pullers for a Hohner headless bass Steinberger tailpiece. https://www.ebay.co.uk/usr/mattydread2012 drop him an email...

Yes, if you spray some Deoxit D5 on some black plastic, like a CD case, and let it evaporate it leaves a lube residue.

Check the wiring of the cable - if it's an XLR is ground on pin 1?

Got a batter one?

Wow, that's a bit flash... A bit like the Tzar's toilet - in a nice way.... 😉

Obviously belonged to Jacques Cousteau...

Similar experiences in my teens. Jack cables were jack cables (and generally crap). But then again no-one was using more than 100W - usually less. Big transistor PA amps were what first raised concerns - MM Electronics rack units were 400W (?) and used XLRs - that's when we started making 'speaker' cables with mains twin core. The jacks themselves were always border line, XLRs not much better, current wise, and then Neutrik introduced Speakons.

Some in-out with a Krackle Killer and Deoxit D5 works wonders. Bending the contact is a bodge - better to order a new Switchcraft jack... which will last decades... The worst are the tubular jacks which need replacing every few (?) years. Avoid cheapo 'gold plated' connectors - whatever they are plated with (it aint gold) quickly wears off and gums up the jack contacts.

Best would be try for spares from the manufacturer. As other NZ poster suggested, try your local model shop for someone with a small lathe who can turn you up some new ones. A harder type of brass or bronze would be better. A cheap fix would be to clean and degrease the holes, fill with metal loaded epoxy (Epoxy Steel etc. from eBay) then cut and file screwdriver slots.

First try re-seating the valves.

Can you reverse the magnets? If so you could do a RWRP humbucking thing. EA in parallel, DG in parallel, then EA in series with DG like a P bass...

Nah, it needs a tone control.

Try lowering the pickup(s) on the G side.

Not perspex - too brittle and will likely crack when drilling fixing holes near the edge. Some sort of styrene / ABS ? What do people generally use? 2.5 - 3.0mm sheet.

Double a piece of wet and dry around a thinner string (the old set will do nicely) and use that to form the slots. Start coarse and polish with fine. Cut slots at the same angle as the headstock - angle A + D slots toward the tuners. Mask off the headstock (remove truss rod cover) and fretboard to avoid scratches. Measure / offer up string frequently. Capo on fret three and 10-20 thou between fret one and string is a good start... You could improvise a GroovBar type of thing to get the depths in the ball park and prevent cutting too deep. Cutting too deep is bad... very bad. Take your time, measure often and all will be well - worst case is a new nut. 😉

As suggested clean the FX send + return jacks. It sounds more like a intermittent dry joint coming and going with warm up Do a thorough visual inspection looking for bad soldering, leaking or domed capacitors, loose connectors etc. To localise, try powering it on with the cover off and tapping / poking with a wooden chop stick. Tap the components and connectors. Flex the PCB. If you do reproduce the fault then reflow the solder joints in that area.

On your exterior door you need to weld the hinge pins in place, otherwise they can be drifted out and the door removed.