[Catkins]

To continue the restoration...

After restoring the PSU, the next chassis I worked on was the CRT enclosure. This was for two reasons, firstly it showed quite a degree of corrosion at floor level like the PSU, and secondly the CRT enclosure contains the EHT bleeder chain/capacitors/focus-circuit, and so it was a logical continuation of the work on the PSU.

I'll let the photographs do most of the talking.

Photo 1 shows the lower half of the CRT enclosure. You should be able to see that there is a thickish layer of white silt covering the bottom, and underneath that is a layer of rust. If you look at the large green capacitor, you should also be able to see that the top half is disconnected (the large connector ringed in black). The resistor which should lie between the two capacitor connections is dangling off the lower connector. This means the upper part of the capacitor has likely failed at some point, and it has been taken out of circuit.

The brown paxolin board at the back of the EHT enclosure holds the EHT bleeder resistors and focus circuit resistors (electrostatic focussing hence no focus magnet around the CRT neck, only deflection coils).

Photo 2 is a composite photo, which shows on the top the rotten state of the cotton wiring at floor level. The rubber EHT wiring was found to be in good condition and not perished. The lower photo in Photo 2 shows the removed paxolin board and the various connections to it.

Photo 3 is a composite photo showing both sides of the paxolin board, and the EHT bleeder chain resistors/focus-circuit resistors. Three of these were found to be open-circuit or very high.

The paxolin board was stripped down, the corrosion removed and generally cleaned. The failed resistors were replaced by high voltage (10kV) resistors. Due to the high voltage drop across each resistor, you should always replace using high voltage types.

Photo 4 shows the new cotton wiring bundles, and Photo 5 shows the replaced wiring and resistors.