Hello all,

I have an AWA 467MA radio as my first attempt at restoration. Whilst I have managed to source the circuit diagram and BOM and feel confident in replacing components that have died (capacitors) and those that have drifted out of tolerance (resistors), what I am seeking is instructions for aligning this radio.

The circuit diagram indicates there are four capacitive trimmers. Looking at the filters, there is only one trim pot on the top, so I am assuming the other is accessed via the bottom?

Whilst I have viewed several videos on how to tune radios, I just wanted to ask if anyone was aware of detailed instructions on how to carry out the process using a signal generator and a meter, or scope.

Thank you

Some nomenclature issues here. A direct couple is one I do for alignment only of the IF transformers of which there are two, slug tuned not trimmer. Rarely does one have to touch the bottom slugs. It is ideal for the signal generator to be reasonably accurate. Normally one does not use the generators ground.

That looks like the signal grid is pin 7 of the 6BE6. That will often be able to be picked up on the aerial gang of the tuning gang. you only need around 50uV so I use a series cap of around 100pF. To much signal will cut in the AGC and you will never get it right. Minimum signal.

I use an oscilloscope usually on the plate of the Output tube as the meter. The meter method (Astor) is done on the low AC range with a 0.1mfd HV series cap hooked to the plate of the output tube pin 2. There were meters like "Peak" 200H that had that feature built in. The meters cap will likely need replacing.

Tuning & setting of the oscillator is C8. Antenna at high frequency last C2; All with no direct couple to the set. Coupling with throw it off frequency. Iron drivers will also throw it off frequency.

https://www.kevinchant.com/uploads/7/1/0/8/7108231/467-ma.pdf

Lloyd

Have just sent a couple of articles on alignment to your email. One from Electronics Australia, one from Silicon Chip. Both are detailed and thorough.

One may find adjustments fairly close, or if the Monkey has been in there, adjusting anything that moves to see if that fixes it (I fix: I see it) they may be miles off.

It is never unusual to have to adjust, via the grid of the tube feeding it, the last IF transformer first. I always adjust the IF first.

If you are not sure: Ask.

Marc

Thank you all for your responses and help.

Ultimately, I am hoping I do not have to touch anything regarding alignment if at all required.

This particular radio did not work at all, did not draw any current. An eyeball of the underside has confirmed all black cased capacitors will need to be replaced, including the two electrolytics to start with.

Have confirmed the transformer is OK.

Have also confirmed the 6X4 power supply valve heater is not open circuit, approx 3.0 ohms. But according to the 6X4 data sheet, at 6.3 volts heater supply, the current draw is 0.6 amps. This implies that the heater element should be 10.5 ohms. Three times what I am measuring. What am I missing?

Regards

Lloyd

Your not missing anything. Your getting a reading on the filement which means its ok. Getting 3 ohms instead of 10 could be anything but isnt a issue.
Remember the .6 amps would be when the filement is hot, when your checking continuity the filement would be cold.

Lloydc, the heater in a valve is made of stuff whose resistance varies with temperature.
You will always read a lower value cold than hot.
Once heated the 6X4 heater will rise from the 3 you read to the 10 quoted.

Fred.

Fred , great minds think alike

Is there a on/off switch on this Radio and is it actually working. If it's not working is it a on/off tone or volume switch. Let us know and tell us what the value of the pott is.

Be very careful as to which "black" capacitors you are replacing. AWA made black cased rectangular caps that were in pF, OR were marked in uμF. It must of cost excess money to put a leading zero on anything of decimal value & that applied to circuits as well.

I have never replaced one of those nor the un-jacketed type of the same thing. Its usually the "mud" type bigger value ones that tend to crack the jacket & go short when the end breaks off.

There is actually a book available through the HRSA which is very detailed. It's in their yellow pages.

It may pay to post a photo to see what you have, to avoid removing mainly caps that should not ever be touched.

The other reasons for sharp photos of everything is for senior moments, when you put the new part where the old one wasn't.

Marc