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Before the chassis is reassembled, every original fastener is polished up to shine - with steel wool.

The scan coils are given a continuity check and the capacitors and resistors attached to them are replaced. Although this is not a 'hiding new capacitors in old' restoration, nevertheless the new capacitors are hidden in black neoprene sleeves so they will merge in better...

The EHT smoothing capacitor is checked and passes with flying colours. This original feature will be used again.


The EHT heater transformer is megger checked for isolation of the windings. It proves to be in excellent condition.

The line output transformer is meter checked and seems fine. It's carefully cleaned - many of the connections are very delicate - and then sprayed with a moderm anti-corona lacquer - to ensure a long life in the future. This appears to be a later type 'ferroxcube' (replacement?) transformer. It will be interesting to see later if the associated component value changes recommended by Baird have been carried out.

The attached EY51 EHT rectifier is replaced as a matter of course.

The array of pots that operate the volume, brightness, focus and contrast is now tackled. All the pots are cleaned, then opened and stuffed with waxoyl. I find this treatment successfully refurbishes 95% of old pots and should ensure decades more of noise-free life.

Never put WD40 on a pot track, or it can get dissolved !


On Monday morning I decide to have a go at reforming the electrolytic capacitors before getting to work in earnest below decks...

I built up this little reforming box a long time ago to Paul Stenning's design. The meter shows a leakage current of 20mA. Although this is just the start of the reforming process, this is a huge amount and doesn't bode well.

A little while later it becomes clear that reforming isn't going to be the way to go on this set! Instead, I'll take them all off, remove their insides and hide new electrolytic capacitors inside.

There is a row of pots at the rear of the chassis - the 'occasional' rear controls including the notoriously unstable (on this set) line hold. The one on the end I thought was the white spot limiter but - looking at the set's card back - claims to be another 'width' control. I'll sort this out later. For now, I replace it with a similar pattern replacement (and parallel resistor) to get its value right. Its wire winding had been clearly broken. All these controls are then waxoyled.
Previously you'll recall I had built up a complete set of good valves for this set. These are now cleaned. Glass cleaner is carefully used, so as not to attack the valve markings. The pins are cleaned and left coated with a thin film of WD40 to discourage future oxidation. Black bases are dressed with Amor All so they now shine...

The frame blocking oscillator transformer turns out to have one o/c winding. Here it is before cleaning. This transformer is removed and the inside from a spare TV22 transformer (previously rewound by Ed Dinning) is substituted inside its frame. This way, the 'new' transformer looks exactly like the old.

The original 2-pole mains connector is today only legal for 50 volts so has to go. It's replaced by an insulated aluminium panel bearing a sleeved grommet, through which passes a new mains lead. In this way, it can be positively ensured that the chassis is always connected to mains neutral, whereas before it could have on occasion been live.

All the more necessary, because the toggle of the nearby mains switch is only isolated from chassis by a thin paxolin ring. Now, to be absolutely sure of safety, the switch body is earthed.


Getting to work now on re-stuffing the electrolytics. The replacement capacitors have arrived this morning from RS. The first one is a real toughie... it's remarkably hard to drill and scoop out the insides.

The new capacitor fits snugly inside the old for easy re-connection..

Andy Beer has kindly found me a suitable replacement dropper for this set. With one subsidiary resistor, it will function as an exact equivalent.

This is what's so nice about the vintage television business. Everyone does their best to help everyone else. You can visit Andy's site HERE.

This unsightly mess is the stack of surge limiter resistors going into the four rectifier anodes - all in parallel.

Most of these, along with every winding on the old dropper, are found to be burnt out. This old set must have undergone a red hot emergency when it finally gave up the ghost before !

Here's the replacement. I have made up a bus bar for easier mounting at the commened ends of the resistors. The original 75 ohm resistors have been replaced with 82 ohm for slightly better buffering, although this value is still less than the 100 ohms shown on the schematic. In this and various other respects, slight differences from the schematic have been found.

At this stage, the capacitor across the mains is replaced with a modern 'Y' rated component. Some of the original capacitors are still to be seen in this picture. They're to be tackled next...

Talking of which, here's one of the dreadful Hunts capacitors. This one was in a safety critical position but nevertheless has 'melted' over a long period where a wire was pressed against it. Either they do this, or more often their cases simply break up. Hunts capacitors should always be replaced, in whatever condition they are in.

The story continues - click here...

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