Hi,
I just finished posting my introduction in the introductions area, so I thought I might talk a little bit more about my new / old toy.

It's an AWA Radio 190 that I recently purchase on eBay.
It caught my eye as I was looking for something that didn't require any work on the case as cabinet making is not my forte.

It appears to been restored a while ago as the case appears to be in great condition and I believe it may have been re-polished.

It works OK, but has a few little gremlins, some of the paper electrolytic capacitors have been replaced, but some haven't. I imagine that a full replacement of capacitors would be a good idea as I intend on using the radio regularly.

After a bit of research online, I have discovered that it appears to have the wrong valves in it.
This makes sense as it was originally a battery radio, and it appears that the chassis has been modified to resemble a similar mains powered chassis.

I'm in the process of finding some appropriate issues of AORSM to help me out.

I have a few questions that I hope some of you maybe able to help me out with.

- Does anyone have a copy of the schematics for the model 190 / 199.
- Does anyone have a copy of the schematics for the model 95, (It appears to be a very similar but AC powered Mantle version of the same radio.

- Can anyone suggest any another 240V chassis which it could be modified to resemble? After looking at an index of AORSM, Volume 4 - 1940/41 looks like it might give some hints

- Ethically, is modifying a chassis to suit Mains AC OK for a restoration?

I never knew what it looked like before it was restored, all the stickers are missing and chassis has been painted over.

Please check out the photos of my new radio in the link below.

Thanks,

Jamie

http://flic.kr/s/aHsjvwATrK

QUOTE: Ethically, is modifying a chassis to suit Mains AC OK for a restoration?

This has been a hot topic in vintage radio circles since the practice of collection and restoration began.

The bottom line is that no-one really has the right to expect someone not to modify a radio for the purpose of bringing it to life in an economical but safe manner. Some will disagree with this and insist that any find should be left as is.

I own several sets which were battery models when manufactured but have since been converted for 240 volt operation. This is not usually an easy task as more needs to be done than simply changing the valves and adding a transformer.

Whilst some people do a neat and safe job of converting receivers, others don't and in their failure to achieve the desired result they end up leaving a receiver in an unsafe 'boobytrapped' condition for whoever acquires it at a later date.

For reasons of originality and simplicity I recommend building a battery eliminator rather than doing a conversion of your receiver. Personally, whilst I am not a member of the ultra-conservative brigade, I wouldn't commit to a receiver conversion. There are dire consequences if something is missed and the set decreases in value if it is modified.

Before committing to this you should confirm that your set is in working order with suitable batteries.

That's a tidy looking set. Yes, replacing paper and electrolytic caps is pretty much par for the course.

Are you sure that it has been converted? I note from the ad that the model 190 is described as "batteryless". I guess the model 199 was battery operated.

Unfortunately, I don't have any AWA schematics prior to 1946.

Going by the style of cabinet, and the other sets shown in the advertisement, 1948 or thereabouts would be the correct era.
What's in the set looks later.
The 12" Rola looks 50's vintage - the shape of the magnet for one thing. The wooden spacers to raise the chassis up look recent. The two pin speaker plug and socket is more of a 50's thing; prior to this a 4,5, or 6 pin valve socket would usually be used - and the speaker transformer mounted on the speaker.
The second grommeted hole next to the power cable is a sign the chassis was once part of a radiogram - another length of twin flex emerging for the turntable motor. Maybe there's still evidence of its connection on the mains tagstrip.
Just on appearances, it looks like one of AWA's last chassis to use octal valves, in the early 50's. The chassis looks like it was always mains operated. One thing to look for is evidence of a dial light switch; sometimes part of the wavechange switch - something only battery sets have, if unsure.
My comments are based on what is viewable in the pictures and may not be correct upon closer examination.

There seems to be a phobia in the valve world about anything that doesn't run off 240VAC, but I guess when you're doing up sets to make a quick buck on ebay or the antique shops, for non technical buyers, these things happen.
I met one young guy in the HRSA who delighted in telling how he went around his district getting all the valves from the the retired servicemen. Then he'd jump on all the battery valves and throw them into the tip. Any battery sets he had were immediately converted to AC. He was quite proud of his array of 'battery' sets too - all with power transformers tacked on, and even with 5AS4 rectifiers slowly overheating the 5V winding.

Battery to AC modifications like that are the kiss of death. If one want's a mains set, then that's what they should get.

Picking up on Cool386's suggestion of possibly a substitute chassis, the only one that I can find with the valve line-up as per the labels in the picture is STC model 250 of 1946/47, for which there was a radiogram version.

What are the current functions of the knobs on the front -- especially, does the band switch have a high tone and low tone position? (And I don't see the tuning knob -- is it on the side of the cabinet?)

Cool386: "Then he'd jump on all the battery valves and throw them into the tip."

What a moron! A real asset to the HRSA ... not!

Whart? Jump on them? I'll reserve my opinion but I wonder if that bloke realised he was crushing gold and keeping the quartz. Battery valves are extremely rare and most who manage to get their hands on a few do their best to hang on to them.

Thanks for the responses gentlemen, it is much appreciated.

I pulled the chassis out yesterday and took some more photos which I have published at:
http://flic.kr/s/aHsjvwATrK

The knobs on the front all work, the on on the left is volume control, and outside knob on the left is the tone control.
The right hand knob is the band switch. It switches the back lights of the dial from MW to SW.
The tuning knob is mounted on the right hand side of the cabinet.

I haven't tested it's SW reception yet as it only has a couple of feet of wire for an antenna and all my ham radio gear is packed away at the moment as I am building a new ham shack.

I'm happy to accept that the chassis isn't what it is meant to be, if it were original I would be more than happy to build a battery eliminator and keep it original.
At the moment, I'm happy to have a safe working vintage radio that will allow me to listen to 3WV on a regular basis.

So considering my current situation, what would be your recommendation in what I should do?

Should I go on the hunt for the schematics of a STC 250, (does anybody have a copy?), and repair and restore it as good as I can?.
I'm not quite the purist to insist that it should be restored to factory condition.
I imagine that trying to find the correct battery valves for it would be a big challenge.

Wimmera Amateur Radio Club, (which I am a member of), has a very large, but unfortunately unsorted collection of valves.

Leaving it as a bastardised 240V version seems to make sense to me considering it's current configuration.

Thanks,

Jamie

I have 3 versions of schematic for the STC 250, but going by the under-chassis photo, yours isn't that model. The reason I asked about the controls is that the 250 circuit shows a simple tone control via the band switch, which has these 3 positions:

1 - S/W
2 - B/C high tone
3 - B/C low tone

... and the band switch has 5 wafers, versus the 3 in your set. The parts list refers to only 1 goat valve shield, versus the 3 you have there.

I don't know what you have there. That's the first time I've seen pots ganged via a belt like that and it may give a clue to those who have seen far more sets than I have.

Apart from the apparently added-on transformer, there are other clues of workmanship that make me think it's a "bitsa", although the dial arrangement clearly belongs to that cabinet.

Given that it's working, and that you don't have another chassis to simply drop in, I'd be inclined to just re-cap it for good measure and love it for what it is.

GTC: Thanks for your thoughts,
Generally looking at it, it appears to have a lot of re-soldering done to it.
There a terminals which have solder on them, but nothing connected to the.
The Volume control and tone pots don't look original and the variable capacitor gang isn't mounted square.

Although considering how old it is, it wouldn't surprise me if these parts had been substituted during it's life as some replacement parts became non existent.

How about this for a thought.
If we look at a chassis from around 1950, as suggested by Cool386, we could look at something like the AWA 525 or 618, 721
These have a similar Valve line up with:
6J8G, 6SK7GT, 6SQ7GT, 6V6GT, 6X5
My 190 has the Valve line up of
6J8, 6U7, 6B6, 6V6, 6X5
Apparently, (according to RadioMueseum.org), the 6U7 is the predecessor to 6SK7 and the the 6B6 is the successor to the 6SQ7.
Just going out on a limb here trying to work out what has happened to it.

Thanks,

Jamie

Adjusting for the pinout differences in each case I suppose that could work and might explain the solder on the unused pins.

Looking at the schematics for the varieties of model 525, I note that it has a 2 position tone switch rather than a tone pot, and it shows a 230/250 switch on the transformer.

Model 618 shows a 4-wafer band switch, and also an input voltage switch on the transformer.

I don't have a schematic for model 721.

I had a closer look at it again today, there is wear marks on the side of the case where the tuning knob has touched the case.
The markings are indicating the original tuning knob was larger than what it currently has.

I'm starting to believe that maybe it has a chassis from a mantle version of the same type,maybe 95 to suit the 190.

I just won two auctions on eBay, so I will have copies of AOSRM '39 and '40/'41 soon, then I can compare it for myself.

I'm looking forward to the challenge.

Jamie