In Future restorations if you have a 80 or 5y3 rectifier valve you need the main filter caps to be rated at 600 volts! They are available and they do surge to 650 volts. Quite often the 80/5y3 will surge past 500 volts on warm up and most of the 450 volt electros dont surge much past 450 volts.

Thanks guys much appreciated
Yes one of the caps I replaced was rated at 600V and I have used a 450V so will replace it with a 600V all others are the correct values

Re resistors I need to replace the following can I ask what do I ask for when ordering

Red green yellow 25 4 ?
Brown black yellow 10 4 ?
Green black orange 50 3 50K and how many watts

I will keep notes of this info for further repairs

Regards
Brian

It is always a good idea to trace it on the circuit. I will never go below 500V on a set with #80 / 5Y3 feeding heater tubes & that also applies to Silicon rectifiers when replacing metal rectifiers where often you need to cut the value of the first cap, before the choke,some times to removal.

Now do I assume these are the old type? Red body 2 green spot on end 5 yellow dot 250K (not made) use 270K Red Violet Yellow order by resistance. 1Watt.Jaycar RR2832 Pack of 2 web page is like dogs dinner.

Brown Black yellow in same type 100K RR 2822 Picture is not it.

50K use 47K 1Watt RR2814

There are other suppliers on this forum.

Depending on the circuit source you should be able to compare the part number to the circuit and it will list wattage. As before; Inventory comes at a cost 1Watt will replace the lower wattage & the voltage rating should be higher.

I do have a thing about purveyors of resistors that do not list their voltage rating.

Marc

An update and I hope you can understand my descriptions

Replaced 250K resistor that comes off the 6B8 tube powered it up and got nothing until I tapped the cap of the 6K7 metal tube with an insulated screwdriver and it burst into life with low volume

Replaced a 50K which eventually goes back to 6B8 much better volume which faded back to low volume after one minute

Replaced a 50K from pin 6 of 6K8 low volume which appears to surge a bit.

Replaced 500k from pin 5 to pin 6 on the 6F6 good volume then fades and surges

Just an observation if I touch the resistor wire going to the 6K8 tube all sound is gone

Could any of this problem be to do with the speaker ?

I always search online for answers and info to try and get things sorted but can someone recommend a good site for learning to read a schematic for beginners

Thanks
Brian

Speakers tend to have a pass fail and nothing else. Monitor the voltage of "B" & see if its stable? Digital meters are not good at that.

An open resistor on a grid can cause the time out as can a bad heater on a valve.

A bad underrated filter cap can cause that but it should be picked up by the voltmeter the set can be destabilised if the first filter cap is wired to ground, not the centre tap.

Marc

Thanks Marc sorry but I don't know how to do any of those tests. I might see if I can find some one here to test the valves for me
Thanks
Brian

A dodgy heater in dim light should be conspicuous as as it dims. I usually make a point of running tubes in a tester as that tends to rid the set of gassy & shorted ones. It is not common for failures but in one Airzone, the #80 rectifier was still in situ; Gassy, wired in & bypassed with diodes. To top that off a 6D6 left its base behind & there was neither balsam on the base or solder on the wires.

That's why you look first as initial assessment.

Most of the time a speaker either works, or it doesn't. Failures are rare.

Basically the rest is just voltmeter work & learning faults. If you study how the elements of a radio work & integrate, that is a big help in determining why it won't work: That bit does not require test equipment.

With a fast acting #80 filament rectifier, it will get mobile faster than the heater tubes can get to conduction. So on start-up I will (using IC clips) have an analogue meter clipped to the "B" rail. What should happen is that the voltage will rise to a surge voltage, only restricted in yours by having a candohm across "B". That can in many sets get close to 500V (set meter accordingly) and then drop back to running volts as the tubes come into conduction.

If the start-up voltage fails to move within a few seconds, or only goes a few volts then there is likely a short, like a filter cap failing. That can also manifest as getting to a voltage below spec & suddenly falling away, normally before tube conduction. That is indicative of a faulty cap on "B".

Fixing is fun & can cause hair loss.

A tube short dragging down "B" substantially, in a tube will often happen as it comes into conduction. Flashovers, normally immediately you get DC.

If a control grid is open, to ground, or the coupling cap is leaking it will gradually see that grid become positive and the tube will become a diode, possibly damaging it.

If a cathode goes open all of the tube elements plate, grids & cathode pin, will move toward B+ voltage.

Thanks for that yes I have a lot to learn
Excuse my ignorance but if I don't ask I won't learn, can the volume control have anything to do with it
Ive noticed that the 6B8 valve is loose at the base as in the glass moves a bit seperate from its base as a process of elimination I will source another valve and try it. Each time I turn it on there seems to be a different reaction
I will spend time tonight online trying to learn about how valve radios work
Thanks
Brian

Corrosion of the tube pins is always possible, removing & replacing often cures that, but cleaning may be necessary.

Loose envelopes & top caps are not unusual, this can be brought about by using the envelope as a grip to pull out the tube by its base and failure to prise both the fly lead terminal off of the top cap and the tube out by its base. I have had published articles on fixing that damage, in many cases.

Breaking the bond & loosing the grounding on metalised Philips tubes is a bigger issue, but it and the loss of the metalisation can be addressed and I have repaired a couple. One appeared in HRSA Radio Waves.

You can get fluctuation from a bad potentiometer, but its rare in carbon ones.

My normal way of dealing with loose tube envelopes, on good tubes, is to use a bit of Araldite on it. I have a Philips 506 Rectifier sitting in a tube tester while the glue cures, for having a loose base.

I use the High strength Araldite, wipe, not plaster some Araldite around the interface between envelope & base (you can leave a couple of gaps) then using insulation tape at not the tension of a tow rope. wrap it around the interface of base & envelope (sticky side in) to hold the Araldite in place while it reacts.

Repairs are not just electrical; Woodwork, Turning & Fitting, Metal Fabrication Work , & sometimes Welding, all get a Guernsey. I have the cabinet of the 3003 PSU in the machinery paint line already.

Photos uploaded to Post 16.

Now after the site locked up yet again:

I have sent Brad a picture of the Philips 506 Rectifier, in its spot in the 3003 PSU. Note only glued in 2 places. The cabinet was corroded & paint missing. It was such that it is not in the best interest of longevity to leave it original.

So there is no way it can be left original but will be sprayed with an industrial paint in the same colour (Dark Blue). Already treated & Primed On that basis I may as well get some film caps & replace the lot in the two cans & make it a worker.

Marc

One hint is to use a old toothbrush or a plastic chopstick and lightly go tapping around the valve tops and under the chassis on resistors or caps. This sometimes reveals dry solder joints or faulty valves or even cracked resistors. Or once the sound fades away spray a bit of contact cleaner on any suspect resistor. This cools them down and often causes cracks to close and the device will work again till it heats up.

All of the valves have been checked and I'm running out of resistors to replace. At the moment I power it up from cold and get low distorted volume or nothing until and it's happened twice now is tapping the tuning gange with a screwdriver it comes alive be it still low distorted volume. Could it be something with the tuning gang as I can only get one station ?
Cheers
Brian

The art of changing anything & everything is called "Shot Gunning" & is rarely successful as it often introduces new faults & it ends up being like a dog chasing its tail.

Fault finding involves methodology also morphing into a systematic approach. Normally one starts at the power supply which in this case, is from the mains socket. You sort that out and move to the audio. Then the IF & front end. The point to be made is that you will not be able to sort out the front end if the signal is not able to progress to the speaker.

If you have a voltmeter (essential) you check the B+ rail and all of the voltages on the valve elements. If they are wrong: Why?

My normal technique as I have the gear, is to fire it up monitoring "B" via an isolation transformer with a "Kill Switch". If it behaves & makes radio noises I will run an IF alignment; any distortion will show up on the Oscilloscope. I will then know, either all is well from IF to speaker, or fix it if its not.

Only then does one attack the front end. Now if you can prove that the IF & Audio is working and the speaker is OK we move on.

A week un-tuneable signal is normally one bypassing the IF and getting in via the AVC / AGC. That means that either the converter valve is is a dud or the oscillator is dead. Pentagrids are notorious for shorting and gang plates getting bent, or shorting via dirt & corrosion. Get a transistor radio really close to it, it in most cases the frequency of the radio station plus IF frequency is what you are looking for. E.g. 1000kHz Will be at 1445 for a 455kHz IF.

Do make sure its on broadcast band.

Are there any perished rubber grommets between the tuning gang and the chassis. If so try replacing them as this can be a issue.