Not too sure on this. Advice please. I have recapped most of my 1937 reliance ( not the console ) but need a 16 MFD ( 20 now ) and two tens can I get these from Jaycar. Thanks heaps in advance.

Carl

In theory a capacitor is a capacitor though there will be no ceramic types that hold 16μF so the short answer is no they can't be interchanged. You will need to stick with electrolytic types and make sure the voltage rating is similar to that on the capacitors you are taking out of service.

Jaycar once sold some high voltage ones but I am not sure if they still do. Only way to make sure is to check their website.

If it has a 5Y3 I will not use less than a 500V cap. & depending on the set that can be underrated.

In some sets where the originals were non polarised I have used motor run types and the Americans are onto a Film type.

The last time I inquired of Steve he did not have what I wanted but may now? You will get away with 22μF but do not go bigger.

Marc

20 MFD OR pF. I will send a pic.

If the capacitor is a ceramic job it'll be in the order of pF, electrolytics are usually in μF as their capacity is far larger. Ceramics are too small to use as filters in vintage radios.

Nomenclature is important as is the position in the circuit. Physical size can be a guide to the range it may fall into.

Most Mica caps were 500V, ceramics likely followed the trend. Replacements for Wax paper & oil types & to keep the inventory down are now 630VDC.

Email sent Marcc

Evatco in Queensland have a range of electrolytic capacitors.

http://www.evatco.com.au/product-list/capacitors/cap-16500ev/

Reply sent.

Jaycar sell 10μF 450V units for a reasonable price, I have used plenty of them in the past without issue. The Philips valve book recommends 10μF maximum for a 5Y3, so this fits in nicely.

This is fine for a radio from the war years and newer, but some older radios have a HT of 400V or more, in which case you'll need a capacitor with a higher voltage rating.

Where one comes unstuck with voltage rating is that virtually none of the modern caps have a surge rating. Mouser (I think) was selling some with a surge rating. The common "universal" used in just about everything Ducon had a surge voltage of 525VDC. It was only a few, Astor built PYE was one lot that exceeded the average 250VDC loaded "B" rail.

The most stress is on the first cap before the choke, but with Filament rectifiers (with no cathode sleeve), Silicon diodes & Metal Rectifiers, they will often cause an initial surge that can approach twice EMF in some radio's before the heater valves conduct.

So suddenly the 250V rail is at close to 500V and I am note impressed with a new 500V cap that let go recently at around 450V.

So when I order these do just say 20μF or is it .20 I am going to see if I can order from the Canadian mob. They seem to have them.

Ok Guys I got onto the Canadian Mob . They were very good and reasonable prices. 10 of the 10 μF and 10 of the 20 μF cost me 89 bucks posted. they also have a very good section explaining the Capacitor values . I did not know that μF was the same as mfd . I am wondering if I can copy and paste it on this site . I found it very informative.

There were at times, charts showing the markings & values of both resistors & capacitors, in some of the cattle dogs and can often be found on the sites of the purveyors of parts. You print & laminate, then use for a coaster.

Caps alone can be marked in Pico Farads pF; Nano farads nF Micro Faras mfd or μF and then as numbers where the last of three is the multiplier so 0.1 mfd / μF is 104 and 0.01mfd is103.

Some very old circuits will have "M" on the resistances and Meg written on others, another trap for young players. "M" in this instance is Roman = 1000 "K" for "Kilo" 1000 was not adopted until much later when things were internationally standardised.

Voltage is often a letter. If you start repairing you need to be aware of all these things and familiarise yourself with them.

Everyone has differing ideas on repairing, I tend to look at it from the brutal commercial angle where time is money & the use of marginal & underrated components, is not good for the set long term nor my business. One learns in 50 years, what will not work, so you do not do it.

I am wondering if I can copy and paste it on this site

No need to copy and paste. A site link will suffice:

http://www.justradios.com/