[miniman82]

No polarity, it's heaters.

The wiring doesn't typically go 'bad' per se, but rather begins to leak HV the older it gets. Thus you won't typically have a direct short in the filament windings (which usually results in an audible hiss and the smell of ozone), but you will sometimes have quite a lot of leakage which tends to drag down the power supply wholesale. Remember that any current lost in the HV circuit is also current which is unavailable to drive the CRT, which is one reason I pay so much attention to the horizontal section. The other being unobtanium flybacks.

This problem is exacerbated by the attractive properties of HV, leading to the accumulation of potentially conductive dust and in turn more leakage. The cure for this is of course cleaning, but if you're gonna go that far you may as well just restring it anyway. I keep a spool of Belden 40kv stuff around for precisely this purpose. Don't forget to look for tin whiskers on the HV tube sockets either, those took my Hoffman out of service for a little bit and the length of them can be really surprising. If you see any, clean with fine grit sandpaper. A rag will just move them around, and they really need to be broken up to be rid of them. Protect bare metal from corrosion with WD-40, or other light water displacing oil. Do not paint!

Your problem happened all of the sudden though, which makes me think a doorknob failed on you.

Let's get systematic about this: Set the chassis up so that you can read horizontal cathode current, and take a reading with the whole circuit in play. Next see what happens if you pull V24 and V25, if cathode current is in a more or less normal range and you have good focus voltage, reinstall V24 and see what happens. Isolate the problem by process of elimination. You should expect to see a slight bump in cathode current with each tube that is reinstalled because of the heater, but if it jumps significantly it may point to a problem.

Don't forget to rule out the CRT either, if it suddenly went gassy it would cause these problems. I hope not, but something to look for. Your shunt tube grid circuit is another area to investigate, the 6BK4 will drag HV down real fast if something went wonky with it. Could be tin whiskers in the HV pot as well, just gotta get to eleiminating each part in turn.