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 Prophesy fulfilled
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 Return to top of page · Post #: 1 · Written at 11:09:18 PM on 21 January 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

From time to time I give prophesies of dire consequences from turning on old valve radios that have been sitting a long time, unused.

Well today was the day, on top of pump & other failures here and being at plan D before noon, I received a desperate phone call from a collector. The vendor had assured him that dad (another bower bird) had sorted this one out (Airmaster?) ….. Yeh right!

So with the claim he had had it running & some trepidation from the collector, it was fired up. I would have loved to been a fly on the wall. The #80 lit up with a spectacular display of sparks & a blue glow…. So undaunted, they got another #80 from another apparently goer:That one fared better, the plates only went red.

So it’s now on my bench, this after getting a blower & brush and removing that which was inside of the first cap from everything in the inside of the pan & cabinet base. Rather like the “Mr Bean” skit with the big bunger in the can of paint. Genuine "Hissy fit"

The last #80 tested OK in the VCT tester, when the collector sheepishly asked me to test to see if they had killed it. They have actually killed something as it’s back biased & there is no resistance CT to ground. As back bias R is part of a long multi-tap “Candohm” type resistor, it’s likely cooked that end.

It’s an untidy incomplete job, that has been got at; It may have been a factory conversion in production, but sockets are marked with 2.5V valve numbers, but it has 6V equivalents with the exception of the Pentagrid which has perhaps had a socket change & instead of 6A7, it has 6A8.

What has happened here, is what makes the job of fixing, one step more expensive.

I have not chased up a circuit (time) but it’s the early round 0-100 550-1500 dial (with hole burnt in from using the wrong globe) 6D6, 6A8, 6D6, 75, 42, 80. (3Gang sections); BC only) Fairly std line up for a set with RF pre-amp.

Marc


 
 Return to top of page · Post #: 2 · Written at 11:30:03 PM on 21 January 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1575

Oh Dear me ( or words to that effect but not printable here ) . I have won a very nice looking AWA 467-MA from eBay. Apparently its a goer but I will never ever believe that until I have tested it. I can see from the photos that its been very neatly recapped but I spied a wire with the insulation falling off of it and two grey 24 UF Ducon electros . Other than that its a beauty. Oh well it looks like you have some work ahead of you.


 
 Return to top of page · Post #: 3 · Written at 11:40:03 PM on 21 January 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Not the worst one, I have a set here with 175kHz If's & both were fried, finding some would be ideal, but finding the time to try & resonate the rewinds is an issue as more important things keep cropping up.

If what I see is wrong, is all that is wrong, & I get a circuit it should not cause much stress on a wet afternoon, sorting it.

Marc


 
 Return to top of page · Post #: 4 · Written at 11:43:40 PM on 21 January 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6013

So undaunted, they got another #80 ...

What was it that Einstein said about doing the same thing over and over again and expecting different results?

I'm also reminded of the old joke: The professional photographer told his Irish assistant that none of the flash bulbs were working. The assistant replied "That's odd, they all worked okay when I tested them".


 
 Return to top of page · Post #: 5 · Written at 12:07:17 AM on 22 January 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

I kept it: I was sent a photo of some firemen with a pumper. They ran out hoses and used the triangular blocks either side to protect the hose from vehicle wheels running over it......... pity they were used on a railway track............?


 
 Return to top of page · Post #: 6 · Written at 7:41:51 PM on 22 January 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6353

To be honest I do not know what more can be done to stop anyone plugging old stuff (of any sort) into the mains to see if it works. Even if we were to set up a dedicated single page website at some easy to search domain name like "electrical-warning.com" and simply say "if you plug something old and dusty into a power point then you are a D/H with a death wish" I am certain that it'd have no effect at all.

Back in the good old days before Facebook and Twitter ruined the Internet I was a server administrator on an Australian IRC (chatrooms) network. My default reason for banning a user who was doing something seriously stupid was "Please pack your computer back into its box and return it to the place of purchase - you do not deserve to own one".

I think something similar applies to people who do stupid things with the electricity network because a lot of people think that 240 volts is a plaything with no dire consequences for a lack of common sense.

The Ebay sellers default comment of "I plugged it in and the valves lit up but no sound came from the speaker" translates into "I am a fool and as an added bonus I also look like a fool" applies. Yes, this is abusive but I've never been one to sugar-coat stupidity.


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A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 7 · Written at 8:04:25 PM on 22 January 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1575

I was 13 years old when I built my first power board . Even then I knew how bad things could get if I wasn't careful. I had the common sense to compare things over and over again to make sure the wiring was all going to the correct place. It really is a matter of sense that's it. some people don't have that at all.

I have to admit that I learnt about how old caps can go bang from a old valve tech that I was lucky enough to work with and befriend. But even then I had a very healthy respect for 240 volts.


 
 Return to top of page · Post #: 8 · Written at 5:09:43 PM on 23 January 2017.
Vince Graham's Gravatar
 Location: Goulburn, NSW
 Member since 28 December 2016
 Member #: 2026
 Postcount: 9

I saw an old set on ebay once, and the description was"works ok but no sound comes out". Staggering.


 
 Return to top of page · Post #: 9 · Written at 8:37:29 PM on 23 January 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6353

If you want some real examples of people who should not be dealing with any aspect of vintage radio, take a look at these threads, and an argument I had with another Ebay member once.

https://vintage-radio.com.au/default.asp?t=103
https://vintage-radio.com.au/default.asp?f=1&th=508
https://vintage-radio.com.au/default.asp?id=debate

It's a case of some people just can't be helped. I should add that the most frequent cause of electrocution in Australia is complacency.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
 Return to top of page · Post #: 10 · Written at 9:37:27 PM on 23 January 2017.
Flakes's avatar
 Location: Adelaide, SA
 Member since 27 February 2010
 Member #: 630
 Postcount: 392

It wont let me just post
"Gold!"


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Valve radios, They just don't make them like they used to

 
 Return to top of page · Post #: 11 · Written at 9:43:35 PM on 23 January 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Now I can identify with & give provenance to the figure eight cables. I had a set come in with severe hum but a goer. Love those, more than half the tests in the book you can ignore. The mains cable was original & just like one of them. I am amazed that it did not start a fire, or kill him unplugging it. Two others were a series of beads, but undaunted, they plugged them in?

More candidates for Darwin Awards.

I have noted that this one is a classic untidy Barbarian job. Too lazy to clear terminals, terminations in mid air, old caps left in there and no idea of how to solder. Naturally most of the resistors not changed or tested are way out of spec.

Unusual way of coupling the grid of the OP valve & it does look original. I have found a Breville 100 with a #42 wired similar, but this one has the field in negative, by the look of it.

Marc


 
 Return to top of page · Post #: 12 · Written at 9:57:37 PM on 23 January 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1575

They are radio techs who repair them.

now if you cut the lead off all you are doing is making work for the tech to find the correct polarity of the electric current that needs to be re -attached so that active goes to the active.

OMG I am just a hobby repairer, even as a kid I knew more than this guy. LOL.


 
 Return to top of page · Post #: 13 · Written at 1:40:27 AM on 24 January 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4347

Yeh! I have been at this game for better than 50 years & its amazing some of the things I have seen.

I have sent Brad a photo of one of the caps in the radio that has a slight issue (The monkey that half fixed it) You will note the "steam boiler*" innocence of the untouched one, compared to the one of exactly the same that I cut the cover off.

Capacitor


That white powder should be on the inside of the can. This is a classic example of a cap that should never have had power applied to it. As is obvious, it has deteriorated from sitting unused and it will of course have lost its polarity ("form"). The insulation that gives these their polarity is an oxide.

This oxide is maintained by a flow of current through them (yes they do leak: they have to). With no current the oxide layer is lost and they present as a short.

* I was told by a Professor, (and have seen examples) that a boiler is one of the things that can explode & demolish everything in a radius of it and not have so much as a scratch on it.

Marc


 
 Return to top of page · Post #: 14 · Written at 6:58:55 AM on 24 January 2017.
Clive Durham's Gravatar
 Location: Grenfell, NSW
 Member since 8 July 2015
 Member #: 1771
 Postcount: 212

I just loved the debate.

Whats is it they say about digging a hole and burying yourself.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Clive

 
 Return to top of page · Post #: 15 · Written at 9:48:28 AM on 24 January 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6353

It was a few years ago now but I still remember the gall of the bloke. The thing is, the buyer is not in a position to make demands at an auction. A product is on the table and people are free to either bid or just observe. In my mind any radio that hasn't been refurbished in the last ten years or so should automatically have its cord cut off so the seller has some protection against possible litigation. Unfortunately we live in that sort of world these days where people don't accept responsibility for their own actions so we all spend more time protecting others than ourselves.


‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
A valve a day keeps the transistor away...

 
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