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 Commodore Identification
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 Return to top of page · Post #: 16 · Written at 5:30:28 PM on 5 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

You sell yourself short Fred. I've seen pictures of your work and can only describe it as 'outstanding'.

As for antennas and radio propagation etc. I am quite at home with those.

I have a few chassis of radios which I will never restore, and I intend to use those as modules for the telescope. Antenna pre-amp, RF/IF and detector, signal strength metering and power supplies will all be built on these chassis, as modular units. This is where I will hopefully be able to draw on your (and others) experience. Chassis metal work, punching out new holes for valve sockets, etc. is where I have no experience.

I will construct my own antenna array. This will be the most inefficient radio ever built, as far as energy equations are concerned. It will draw relatively large amounts of power for very little results, but that is not important here, I just want to be able to fire this thing up from time to time on weekends where off-peak power rates apply, watch all those heaters glow and enjoy a cold beer while listening to the cosmos hiss.

Sheer madness, can't wait till it's finished.


 
 Return to top of page · Post #: 17 · Written at 7:31:01 PM on 5 September 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1470

Sounds like you and Fred should colude on this . you do the chassis and fred ressurects a non existant cabinet hey lol.


 
 Return to top of page · Post #: 18 · Written at 8:02:58 PM on 5 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Hmmm----didn't think about a cabinet. Now that you mention it, a nice old ex Telecom equipment rack would be perfect.

I was given one years ago as a non-official retirement gift, I promptly turned it upside down on four red gum stumps and made it into the most solid work bench you have ever seen.

I installed it in the garage of my old house. How I regret not taking it with me when I moved. Many regrets from those days, I dare not write here the goodies thrown out/left behind. Kicking myself, but, live and learn, as they say.


 
 Return to top of page · Post #: 19 · Written at 8:41:09 PM on 5 September 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 5514

I dare not write here the goodies thrown out/left behind. Kicking myself, but, live and learn, as they say.

Keep an eye on Gumtree. You never know what's going to turn up.


 
 Return to top of page · Post #: 20 · Written at 9:52:44 PM on 5 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

ARRL handbooks I think have antenna's if we are going into off world stuff.

Back to the Salt mines: The 6A7, 6B7 & 6D6 were released in 1934; 42 well before. The resistors look 30's.

Now the interesting bit: Aerovox is not Ducon and it has both. The resistors & Aerovox could have come via Continental Carbon Co & Simplex sold their stuff.

Ducons were also made across the ditch & the one rolling around on the floor that came out of one of their sets has made in NZ on it: Check

Mud nest was made locally.

Marc


 
 Return to top of page · Post #: 21 · Written at 7:41:50 AM on 6 September 2017.
STC830's Gravatar
 Location: NSW
 Member since 10 June 2010
 Member #: 681
 Postcount: 878

 
 Return to top of page · Post #: 22 · Written at 9:28:01 AM on 6 September 2017.
Robbbert's avatar
 Location: Sydney, NSW
 Member since 18 September 2015
 Member #: 1801
 Postcount: 1178

Thanks for the extra photos. The underside looks clean and easy to work on. If you're intending to make it work then I'd replace the 5 wax capacitors (ducon and sealdtit), as they would have turned into resistors by now. The electros may or may not still work after a slow application of voltage to rejuvinate them. It's a bit of a lottery with them.

Very important - make sure the speaker field coil and transformer are conducting before applying power. After a new 6A7, I'd expect it to start making sounds.


 
 Return to top of page · Post #: 23 · Written at 10:14:38 AM on 6 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

I would neither dare to reform, or leave any electrolytic cap, of that type in it. as it's a #80 500V minimum electrolytics on "B" :Check resistors as you go. One hopes the new cap is the right value? I have a HMV here that had wrong parts.

My advantage was a circuit & experience that said it was probably wrong, when I looked at it: New work equals suspicion. Then, "is in on my bench as something done is wrong", often like this HMV, it is.


 
 Return to top of page · Post #: 24 · Written at 10:29:52 AM on 6 September 2017.
Fred Lever's Gravatar
 Location: Toongabbie, NSW
 Member since 19 November 2015
 Member #: 1828
 Postcount: 671

Think of this as the first step to making a radio telescope. Get this set working, switch to short wave and listen to Mars from your dish antenna.

1/ replace twin death cord with 3 core power cable and connect the greenish wire to a chassis lug. This is an absolute must!
2/ replace all wax and electro caps with newies trust me they will all be leaky or go up in smoke.
3/ lift one end of each resistor and measure, if over 20% replace with 1 watt from Jaycar or the other place like Altronics or somewhere like the junkbox.
4/ scab up a permag speaker, use a 240/12 volt power tranny or some output tranny to couple.
5/ scab up a choke to take place of speaker field, or use a old power tranny primary or stick in a 1000 to 2000 ohm 10 watt resistor to get the HT to the valves.
6/ apply limited power say 1/4 volts via a variac or say through a 100 watt old school light globe and form up new electros.
If the power tranny does not smoke and your ECLB does not trip up the volt level to full 240 and watch for glowing heaters, unwanted smoke issue.If nothing smokes and ELCB is still hanging in you now have a chance. Check the HT level is not stupidly high, 200 to 300 volt?
Start off without that 6A7 and see if the audio works and I assume you have to fix some of those top cap leads that look missing.
7/ get new 6A7 or find that the original is ok and then connect aerial wire to dish, listen to Mars.
Simple!
Fred.


 
 Return to top of page · Post #: 25 · Written at 1:21:44 PM on 6 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Thanks everyone for good advice and interest.

Restoration may not happen, I have several radios which I will not replace original components. These are my 'museum pieces'.

My restoration efforts are radios from 1948 to 1958. I don't mind doing total recaps to these.

Older ones I clean, dust and polish only. The components are part of their historical charm.

My main interest with this particular chassis was identification, and you guys have given me several good leads, many thanks.

Regarding the RT, I have several basic working models, my latest is made from a salvaged varicap VHF/UHF tuner module, coupled to an IF/Video detector module. Video output is fed to a monitoring amplifier and signal strength meter. Video output, of course, is AM noise, not pictures. It is this noise which I study.

There are some interesting 'natural noise' sources to be found for anybody interested in such things, as long as you have the patience to weed out the other hundred or so made-made electrical sources continually swamping the 'good stuff'.

The Valves Only RT is more of a nostalgic novelty rather than a serious contender for my solid state gear, and for now is quite low on the 'things to do' order.

Cheers and thank you everyone.


 
 Return to top of page · Post #: 26 · Written at 3:57:32 PM on 6 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

If you want just AM noise I sure can help. RF from power lines, The NBN set up, different lights with electronic ballast, one computer & the PSU from a set of lights on the work bench. Unlimited entertainment.


 
 Return to top of page · Post #: 27 · Written at 4:52:22 PM on 6 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

Yes, sadly, this is the problem. Once upon a time we had a species living amongst us called Radio Inspectors. Their job was to keep the airwaves relatively noise - free so it could be used for serious communications.

These guys were so good in their job that they actually had the power to tell the SEC to clean their arcing insulators, and the SEC would comply, as we all would if our emissions strayed over the top of the other guy's frequency.

We are now swamped with every possible spark, arc, spurious data spurts and streams rich in harmonics spraying crap everywhere, and thanks to the growth of digital transmission techniques, nobody notices or cares except fossils like me still playing with antiquated 20th. century analogue AM gear.

By the way Marcc. You mentioned the 42 pre-dates the other valves. Does this mean there is a possibility that the rest of the valves are not original but more modern equivalents??


 
 Return to top of page · Post #: 28 · Written at 9:26:31 PM on 6 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 3967

Valves are a way of dating: 42 was released 9/32 in 5/35 it was reincarnated with a changed base & was called 6F6. So assuming they built with the latest valves. We are looking at a radio likely built 1934 but after that date could have been still built with the same circuit, but with 6F6.

6A7 had a base change & became 6A8 (originally starting as 2A7) 6D6 had a base change & became the still cantankerous 6U7. Similarly 6B7 became 6B8 & #80 became 5Y3.

So that has nothing to do with wrong valves.


 
 Return to top of page · Post #: 29 · Written at 3:06:02 AM on 7 September 2017.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1490

The ARTS&P transfer has a B so that makes it 1935. Easy!


 
 Return to top of page · Post #: 30 · Written at 3:36:12 AM on 7 September 2017.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1490

It's a Tasma. I can't tell you the model because I'm on the other side of the world right now and I can't open PDFs on this device. But it's a bit older than my Tasma 360. Look under Tasma on Kevin Chant's site. The 360 has an 'audio' volume control, yours has no AGC and a 'bias' volume pot. Tasma models are not necessarily in number order.


 
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