I had been after one of these for some years due to the design and a few years ago I managed to get one from a very nice seller in Liverpool.
After some time in slumber in my workshop and some persuading that dual standard sets aren't very difficult even for those with relative inexperience (as Sideband suggested), I got it up on the bench. (My hernia recovery helped in this decision, originally I was going to tackle my Ultra V14-53, but as that's heavier, I decided to put that one off and restore this one first, so I could restore for some of the time I was off, when my surgery was well enough to do it).
An inspection inside revealed a set that had been dry stored, but was covered in coal fire dust. More importantly, the standards switch was left untouched, no soldering shut or ripping out! The spring on the standards switch was quite rusty but still had considerable spring in it so has been left alone. It looks a right swine to disassemble just to replace the spring!
A snip of a mains filter cap and first power up, very promising results, just a raster with cramp at the bottom. Applying testcard also revealed a few linearity problems, too.
On the second night, I decided to get down to some diagnostics and component changes. Firstly, a replacement of the cathode bias cap and resistor did bring some improvement to the frame cramp but not enough. Now, the testcard was folding over on itself at the bottom and top and the height and linearity controls wouldn't stretch the raster any further, just cause more foldover. So, the frame linearity circuit was checked and C90 and C88 were tested leaky and replaced. C88 I had a perfect value replacement in stock (0.01uF), but the 0.03uF C90 had to be replaced with a 0.022uF, near enough for almost perfect linearity. Again, the linearity controls didn't sort this, but checking R111 (100K) and R113 (120K) revealed both to be just over tolerance, so they were replaced. Perfect linearity now.
The next night a bit more progress, but a new fault - frame lock very weak, which within 30 seconds disappeared entirely. In the past, the frame area had been repaired before, with Plessey caps. C79 (0.003uF) was faulty so replaced with a 0.0022uF. This restored an oscillator running at half speed, with correct lock only achievable at one extreme end of the vertical hold pot. This was revealed to be the work of the previous repair man, who had put in a 0.015 Mullard tropical fish cap here. Replacing with the correct value restored normality.
Next up, a slight rippling on the line stage which was not viewable on my photos - C100 (1uF) (HT rail decoupler electrolytic for the line and frame stages) was checked and found to be the cause of the fault so replaced. Perfect line scan. Line lock was weak, so the line sync capacitor C104 (0.01uF) was checked and found to be crumbling to bits (well, it's a Hunts). The replacement resulted in strong line lock.
Next up was sound, which was distinctly buzzy in spite of position of the cabling or the system being used or the fine tuning. So, a component fault it had to be!
C77 and C75 had both gone totally o/c so were replaced, slight buzzing on sound now, but nothing more than is normal for a TV of this period.
Testing the UHF tuner, which is of the valve type revealed very good results. I was expecting low gain or something from these, but no, absolutely fine!
Next, on both VHF and UHF, there was a black streaking to the right of anything bright on the screen that didn't show up on testcard. Both C35 and C41 looked distinctly unhealthy so I replaced those. Now that has been resolved.
Next up, a strange fault. Whenever VHF was used with no UHF plug in the socket, the picture would be OK and vice versa on UHF with nothing in the VHF socket. But with both plugged in, a slight buzzing on UHF and severe cross-patterning on VHF. Giving one of the VHF tuner valves a new screening can didn't resolve the issue (the old one was missing when I first took the back off). A close inspection of voltages around V3 revealed the screen grid was at 104V and the anode at 201V. This revealed R15 (39K) and R16 (68K) had both gone to over twice their value! After replacing these but before powering up the set again, I tested C10 (0.001uF) as I thought this could be at fault for the rise in value but nope, it turned out to be fine! As a result, the voltage for the screen grid of the valve was now down to 25V, 20V lower than it should have been, but I thought my digital meter may have been loading the circuit. The anode was now at 190V. This made no difference either, but as this was the point at which I had noticed something else which I was certain to be the cause, I stopped investigating around here.
Purely by chance I had found that the core of the VHF coaxial had split from the core of the VHF aerial socket and that someone had wired in an ordinary cable between the socket and the VHF tuner, with the original cable still present, but only connected by it's screening side.
Taking this cackhanded but well hidden work out and soldering in a new brown 75Ohm coax resolved that problem!
Next was the simple job of resoldering all of the components that were (just about) handing on to their solder at the factory!
One accident with burnt off track, though. Even with my iron down at 25W and the tip being rather small and the iron not touching a joint for more than 4 seconds and the track still began lifting slightly.
A final adjustment of geometry and both linearity controls and height restored picture perfect to 405 and 625.
Now, just a cabinet repair.
What needs doing:
All front panel gold trim, including the gold strip repairing, a new foot and the cabinet revarnishing/restaining and the UHF tuning dial needs looking at, the tuning dial and the fine tuning ring behind it are intermittently twisting each other when one is turned. Do these both turn independently (assuming it has a fine tuner) or is the ring just a backing to make it look a similar design to the VHF tuner?