Hi all, new to the forum, retired TV/Audio tech now dabbling in tube musical amplifiers and looking at getting into some early am radio. Came across this little leather case HMV J316 set,and would like to get it going. Has some low ''white'' noise from the speaker and probing around, the audio amp output appears to be there. The fault appears to be it the early stages, maybe in the IF, but as this is my first RF project, a circuit would be nice, but as yet I haven't been able to locate one via my contacts in the TV industry,which is probably the norm for one of these. Maybe someone has some ideas on what to look at with it, as I am going into it blind at this moment. Regards. Geoff

Welcome to steam radio.

Your radio doesn't appear here
http://hws.org.au/RadioHistory/manufacturers/HMV.htm
but a lot of information remaining is incomplete.

It would be handy if you could come up with a list of the valves in the radio and a year of manufacture. Have a look for date codes stamped on output transformer or speaker. Sometimes there is a date left by a quality control inspector on the chassis somewhere, usually in pencil.

You could also post a photo - this can be done by emailing it to Brad.

Hopefully then someone will come up with an answer.

Take care - the collecting bug is virulent.

Thanks for that, it is solid state, not valve. Will post a pic. Regards.

Some of that "white noise" in early transistor sets, was actually due to the leakage withing the transistors themselves.

Marc

All good, it;s a J316 set, and a circuit would be much appreciated if anyone has one, or a place to find. Regards

One HMV J3-16 circuit at the link below.

HMV J3 16 Circuit Diagram

You can probably trace which stage has the fault, without too much equipment. If the hiss varies with volume setting, then the problem is likely in the front end.

Even without the circuit, a photo, or the numbers on transistors, may show what is in it, that is known to fail. What are proving unreliable are the electrolytic coupling caps (what's new, with them drying out) and some little 1/4" by 3/8" axial caps, that just love cracking & exploding.

It has also been noted from my experience & other sources, that Mixer / Oscillator, and dedicated Osc. transistors are dying at an alarming rate. It is not always possible to find a transistor that will oscillate in the current circuit.

Marc