Also on the issue with condenser replacement:

Whilst it is true that Ducon condensers had a wide tolerance range at manufacture I would always recommend replacement with the same values, paying special attention to the voltage rating.

Electrolytic condensers are readily available in 10μF, 16μF and 22μF values at ratings of 450 volts from Australian Vintage Wireless in Perth, WA. Contact details are on our Service Directory. If you are going to go to the trouble to buy condensers you may as well get the correct type.

Great many thanks,

Do you think that that three other capacitors / condensers are .25μF rated at 500vdc,

They are all dimensionally the same size and colour, a light brown wax coated about 2 inches long by 1/2 inch across. one is marked 0.25MFD, 2nd marked .25 MFD, and third marking is 25 MFD.

Would I be right in assuming that these older paper condensers would not be 25MFD at 500vdc at the actual that they are.

The rest are "Black Beautys" with no markings so they will not be replaced for now unless I can track down a circuit diagram.

Marcc, the positive of the two 16μF electrolytic capacitors appear to be connected to the speaker transformer.

Cheers Roger

Get hold of a circuit diagram at all costs. It will often be the only way to confirm condenser values. By my reckoning the wax coated condensers will all be 0.25μF and two of them will simply have worn markings however I cannot guarantee it. A lot of radios used several condensers with this value and they can be replaced with brown coloured polyester condensers with the same value and voltage rating.

The idea of the 16μF condensers is to help prevent mains hum coming through the speaker.

This is why we need a circuit diagram.

One 16 mfd may be on the speaker transformer. The other the Cathode of the 6X4. This is where lack of data becomes a hassle.
Even a photo may be of benefit.

There are two things that look like a speaker transformer. One is the real McCoy and the other is a choke. The choke has two wires the speaker transformer four (and two heavy ones go to the speaker). The only time that both positives end up on HT is when the choke is in the earth lead of the transformer. In this case one16 mfd cap. would be insulated from ground

The paper caps are commonly brownish yellow and wax coated and commonly in the range from 0.01 to 0.47mfd in a range from 200 to 400WV in most domestic radio's.

Most of those "Black" Mud capacitors did have numbers on them, often this was in brown or yellow and damn difficult to read. Often they were underneath to make ID as difficult as possible. AWA did make a rectangular Mud like Silver MIca (rarely fail no touch) there are also brown bakelite coated ones that are Silver Mica (rare failure no touch). Some mud's lost their jacket, that sent one to the circuit.

25 mfd is not a paper, it should have a polarity on it. Some older ones had a red slug in one end, that was positive. I would expect one of those to be on Pin 2 of the 6AQ5 negative too frame. These can be mistaken for papers.

For the benefit of the inventory and the fact that most suppliers etc. have standardised with non polarised caps. For valve radio's just buy 630 Volt DC types Like the tubular Metalised type offered by those such as EVATCO. The red greencaps often do not have the range of values and their leads are often too short.

Keep hunting for a circuit, that will save a lot of hassles.

Marc

Thanks so much, circuit diagram a priority. Kind regards Roger

Roger,

Study this site and you will find educational and of great help.

http://funwithtubes.com/

Regards

Rudy

PS. Stick with it.

Sorry,
Meant to put "it" after find.
Rudy