In an earlier post talking about the transformer, I suspected that the orange wire may be incorrectly placed as I jumped to the conclusion that the tag marked S may be a shield. I have one of these transformers on the bench now and see that there are 2 S tags, being the secondary winding, of course.
Blame it on a "seniors moment"!

Harold

Going back a step the first assessment starts a the power plug/s, then you look at the rest. Assessment is all about working out if its not only safe to power: Its also all about the viability of repair if it isn't.

At this point nothing is replaced.

One must familiarise themselves with the transformer before touching it. If you get the circuit diagram, convention 'should' show an earth, or brush symbol connected to the core of the transformer, if its a shielded type. When the windings are isolated you may find one wire that appears to be open circuit, which is, in a good transformer the shield.

If I isolate a transformer I will earth leakage test it & HV test it between windings.

Once you become a senior citizen, that sort of thing is expected. although I see some younger that can't wait that long.

Unfortunately in this thread all the valves were replaced. I got no idea why.
Then by the second owner, all the paper caps and electros were replaced.
This is before any assessment had been made.
Although with dim bulb as a safety net, Murray is now getting enough HT that should make the set work. It appears although not proven yet that the mains transformer secondary winding may have an imbalance due to I assume overheating at some point in the past.
As Marc says early assessment would have written it off. And saved the cost of valves, caps and time.
Possibly providing the transformer has no leakage between windings or to earth it still may be serviceable, or be modified with modern voltage doubler circuit or something similar.(if it is indeed faulty).
But at this stage it is still not making any noises in the audio section probably being a man made fault, and I believe Murray is still working on it.

Yeh! I maimed a hand & so far I have as noted made a pulley for one of apparently eight sets. At some stage I also need to strip down a tractor engine & that's always entertaining: Some designers should be forced do it, so they realise the error of their ways.

We really have no idea as to what the previous characters really did & therein lays the problem. When I see rework alarm bells ring. As I have noted recently, I saw an unexpected valve in a HMV & it was wired wrongly, had a wrong coupling cap & I have no doubt whatsoever that no resistors were checked, as I tossed about five.

That tells me that the set was likely flipped, as previous genius had no idea as to what he did wrong. So it really is a case with this one, of checking it against the circuit. & checking everything that looks like it been changed. One can check the AC voltage of the HV winding with the rectifier out. That creates no B+. It might be like the HMV where I spotted fault one without powering & noted it was never going to work unless I fixed the thing first: I do not use a dim bulb.

My warning as always is, where you have a HV secondary with a CT like 400 - 0 - 400; Make sure that if you measure across the outsides (800V) make sure that the meter can handle it. Many modern ones can't.

Hello , all
Thanks for all your input, I have learned much, and improved a little. Whilst at first, I read that you should replace old caps , they're all likely a problem, I also appreciate the methodology of analysing, fault finding, repairing. Ive learned way more through this process, than when I just replaced a bunch of old caps with shiny new ones.

At my last entry, I still had no audio, and very low voltage on pin 1 of 6bd7. And I did not own a digital multi.

I now have around 60 volts , and I have audio. I'm certain that you would like to know how it was fixed, and so would I!

I cleaned the pins of two valves with 100 grit paper, they were quite black and rough. I got this idea from an old V R post.
I lifted the end of that C11, 150 pf again.. It shows very high resistance.
I replaced r14, which is on the tone pot. It read very high. I don't think that would have fixed the problem though.
I bought a digital Multi.

After doing these 4 things, and staring at the circuit and diagram for 3 days, I tried it, and it went. I even patched in an mp3 player, and got some tunes through the radio. Perhaps it was a damned good staring at that fixed it. Kinda like the "Fonz" banging on the side of the jukebox..

Now the original reading I did, told me to replace all paper and electro caps, but "mica caps rarely die". Well I have four micas in this machine, Ive lifted 3, and all 3 show medium to high resistance. So I'm on the hunt, 3 of them can be bought from ebay - Evatco is nearby in Brisbane, but I have a 480pf on the oscillator coil which is not too good, it seems I can get a 470 or a 500. It looks like +- 1/2 or 1% so I need better than what's on offer there. Wes components catalogue have a similar story.

So that's about it for the moment. Until I find some little caps.

P.S. The radio was given me, in dead condition, the old feller had replaced valves, that was the sum total of his repair skills. I took it politely, intending to bin it. But then I figured it was a perfect learning opportunity. It has a good sound fascade, dial etc, but the top and sides enclosure has seen better days. I'll deal with that IF and when it works again.
P.P.S I'm not measuring my fingers.

Cheers, Murray

One can have fun with finger counting. Outpatients like to ask fifty questions. So when triage got around to missing digits, like fingers & toes, of course the LH was declared to have one finger missing: Much confusion as she counted four fingers on thumb?

Then on being informed that that one had originally six: She could not work out which was the middle. Can't take some people anywhere.

Now how did you measure those Mica caps. They have to be out of circuit, the ones on oscillator coils etc are often part off it & unmarked as they are an entity. The tuning Gang Oscillator & Antenna coils are a matched set and not necessarily, built by Kriesler. Messing with them is a no no.

Did you take one end of the cap out of circuit? The only set I have seen that had all caps & resistors fail was an Astor RK & I suspect that was lightning, valves were ok.

The 480 pf cap (C5) is the padder to keep the dial tracking correct, hence the small tolerance figure. If it really needs replacing, I suggest using a couple of caps in parallel to get as close to 480 pf as possible.

I concur with Marcc that modifying any of the tuning parts should be avoided if possible.

Harold

Yes, I lifted one end. It is a separate component, rectangular box shape, it looks similar to Bakelite , with axial leads. The value is printed on one side with dark ink. All four Mica's in this set are the same in appearance. I am aware of the importance of getting these right. You can buy 470, and 500pf, but that's not close enough. As suggested that I put two in parallel to get the value, I believe they should be equal- i.e half the value, so they work equally. Is this true?

I still wonder if this set has had lightning strike. The resistor on the antana coil being cooked, and also the rubber mounting grommets on the tuning gang have been melted. Molten. However one should say it... And also the fact that quite a few components are dead.

Given that any capacitor you buy will not be a 2 1/2 % tolerance, I would be inclined to try a 470pf . If you can measure capacitance and have a couple of caps, you could try selecting one that is closest to 480pf. Or if they are spot on, a 470pf and a 10pf in parallel equals 480pf.

Having said that, a slightly different value will alter the dial tracking, but as any stations marked on the dial may have changed transmit frequency anyway, does it really matter? You could still set the alignment at both ends of the dial, the mid dial alignment will be out slightly, but as I said, does it really matter?

Harold

There are two different test for a Non Polarised cap as there is more than one way they die. Unless it is a dead short or close too, a dead short a conventional 1.5V ohm meter is useless.

Some crack their jacket & short , others like Wax Paper: Leak. With the ones that leak, they may still test to the right capacity with capacitor tester. Electrical leakage, manifesting as resistance, can allow enough current to flow, where it is a coupling cap to wipe out the grid bias of a valve. My normal leakage test (for non polarised caps, is with an insulation tester at a voltage close to the rated DC voltage of the cap.

Those who have a Paton VCT & similar would not that it uses, for HV ones, around 225VDC in series with a Neon tube. In both cases this works on the fact that a good cap should not pass DC.

One end of the cap must be out of circuit.

For those with one of those fab little Chinese testers that test Transistors, caps, inductance etc .: Any pre-existing charge within a cap, can / will destroy it. Others have done it: no need to test for validity of comment.

Re the Mica caps, the ones that are connected to high voltage are the ones most likely to be at fault, especially if they are "Silvered Mica" types (usually marked "SM". This is a result of silver migration through the mica insulation. The ones on low or zero voltages should continiue to be "bullet proof" as we historically thought Micas were. In this case on the plates of the 6BD7 and Output valve 6M5 or 6AQ5 should be checked or replaced.