I'm either stupid or a sucker for punishment.

[Refugee]

There is not a lot of solder on mine.
Just use a little bit of rework flux and a hot soldering iron.
It just slips out of the U shape if it gets too hot in use.

[boater sam]

Will do. Should be simple.
Wonder what the solder is? Woods metal?
Sam.

[Refugee]

I have no idea about the kind of solder used.

[boater sam]

Had the time to replace all the pitch paper capacitors today.


Set works, tunes stations but with bad whistling either side of strong stations and obvious IF oscillation.
A quick valve swap solved nothing so its going to be more complicated than a recap.

Soldered the thermal link back together and hooked it onto both hooks on the transformer, done.
 Fitted a fresh 3 core mains lead and earthed the chassis, transformer is not distressed, I feel happier with a proper lead and an earth rather than my temporary two core suicide lead.
Oh, and fitted a new light bulb, one of the originals is still working!

[Terry]

Are there any capacitors in the IF strip that you haven't changed? Are there any missing metal screening cans?

Another possibility that comes to mind is the possibility of oxidisation of any solder tags if they are riveted.

Could be high ESR in the electrolytics. Should be possible to prove by temporarily shunting them with a suitable polyester or similar cap.

[boater sam]

Thanks Terry.

The sun is shining so its boat painting today.

Did replace all the paper capacitors, all that are left are the Philips tubular ceramics which are usually reliable. But they will have to be checked.
There are many riveted earthing tags, already thought of that one, its a favourite  for this problem. I will go around bridging them all.
The electrolytics are all new and there are low value poly caps across the HT rails now.
The mixer/frequency changer and the IF amp valves share a screen resistor and capacitor, I'll try splitting them if all else fails.
Had the same problems with a couple of Bush chassis with EF39s before and the judicious addition of a grid stopper often works. Its not common with EF41s.
There is no sign of the twiddler, thank fully.

[Terry]

Would this be of any use to you? https://golbornevintageradio.co.uk/forum...p?tid=7022

It was intended for finding decoupling faults in TV IF strips, so you might need a different value capacitor.

[boater sam]

I use something similar on pcbs but with a hand wired Philips set its a rats nest of unsleeved component leads, too many shorts/shocks.

[boater sam]

Played around with this chassis without finding any simple reason for the howling instability.
Its not earth rivets or paper capacitors, there are no valve screening cans fitted. HT line RF decouplers are new and correct. Valve swaps do nothing.
The internal screen across below the chassis  is in place.

Did find a cracked ceramic insulator on the aerial side of the tuning capacitor. I unsoldered the 3 wires and carefully removed tha capacitor with the drive wire still attached. A dose of Araldite secured the insulator. I managed to get it all back together without losing the drive, Philip's multiple wire tuning drives are not to be disturbed if your sanity is to be preserved.

[Terry]

This might be worth a try. Get a strip of copper laminate or metal. Insulate one end with tape to prevent shorts, etc. and use it as an extension finger by gripping the uninsulated end and probing the rat's nest.

See if the extra capacitance this provides has any effect on various parts of the circuit, other than detuning, of course.

Direct further examination to any sensitive area this identifies.

Agree with your comments about Philips tuning drives! I defy anybody to rewire one without a good diagram - and even then, it isn't easy!

Hands up all those who think they've been successful after multiple attempts and then found that the dial pointer travels in the wrong direction!