Welcome to Australia's only Vintage Radio and Television discussion forums. You are not logged in. Please log in below, apply for an account or retrieve your password.
Australian Vintage Radio Forums
  Home  ·  About Us  ·  Discussion Forums  ·  Glossary  ·  Outside Links  ·  Policies  ·  Services Directory  ·  Safety Warnings  ·  Tutorials

General Discussion

Forum home - Go back to General discussion

 Don't power up vintage electronics - the message is getting through!
« Back · 1 · 2 · Next »
 Return to top of page · Post #: 1 · Written at 8:30:27 PM on 28 September 2017.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 1906

Yesterday on American Pickers they found an early portable TV. The issue of "Does it work?" soon came up.

The guy got it right. "Never plug in vintage electronics without first getting it checked by an expert".

Good to see.


 
 Return to top of page · Post #: 2 · Written at 9:40:49 PM on 28 September 2017.
Marcc's avatar
 Location: Wangaratta, VIC
 Member since 21 February 2009
 Member #: 438
 Postcount: 4344

I did post a link to an idiot on Utube that was spotted by someone on the American forum, demonstrating a way to get killed, by powering. I believe there was consensus that Utube was to be asked to remove it.

I have told a local collector never to power: Despite this he and another did on a set that "Daddy" restored (who knows when). That saw the demise of one #80 in spectacular fashion & the powder coating of the pan & floor. Fortunately the transformer survived: That was my major concern.

This is what can happen: Many of those old AA5 American sets (and European) have no transformer and could "unchecked" prove lethal and I have seen several local sets where it is miraculous that they were not electrocuted just unplugging it.

Agree: valuable & excellent comment.


 
 Return to top of page · Post #: 3 · Written at 9:42:17 PM on 28 September 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6012

It's good to hear that the message getting out. Whether or not it's getting through is yet to determined.


 
 Return to top of page · Post #: 4 · Written at 7:10:11 AM on 29 September 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

Marc, the link you posted to that video should still be here somewhere. I wonder if people are still bagging that bloke. I remember having something to say about it there. The bloke was a walking disaster area, from memory.

UPDATE: https://vintage-radio.com.au/default.asp?f=1&th=1162#9398


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

 
 Return to top of page · Post #: 5 · Written at 4:02:40 PM on 29 September 2017.
Flakes's avatar
 Location: Adelaide, SA
 Member since 27 February 2010
 Member #: 630
 Postcount: 392

Gota Love the KFC buckets on the desk.... Quality storage of parts Sad


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

 
 Return to top of page · Post #: 6 · Written at 7:51:59 PM on 29 September 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

This gorgeous Philips may just qualify into this discussion.

I love this receiver, it's got LW, fantastic listening to NAV Beacons spelling out their call sign in Morse. What's more, it is exceptionally light for a valve radio.

Yep! No mains transformer. It works well, outstanding sensitivity, very pretty dial lights and, oh yes, all it's metal parts are live---------

240V WRTE.

It failed to kill its last owner (even though he was well earthed) because the RCD tripped when he touched the volume shaft (no knob)

That is how I ended up owning it, because it kept "blowing the breaker." A very lucky man--there are still plenty of houses in VIC with no RCD protection. ( Shouldn't the government worry more about this than ramming greeny light fittings down peoples throats)

Check out the mains inline wire-wound assembly. The original (green enamel) cracked and sagged, so clever repairer attaches wire-wounds across the cracked assembly.

The assembly sags and one of the WW resistors makes contact with the body of the audio output tranny.

Result: Live chassis.

Now, a question for historians. All through my training I was led to believe that we had the safest electrical standards in the world, and these standards were based on England's standards.

So how is it this set (made in Great Britain) is not earthed. Did Australia have an earth-mains system before England? Surely not!

And this set is not that old, by the look of the valves, I'm guessing circa mid to late 50's. (I shall research this later when I hunt for a circuit diagram)

Apologies in advance if I cock up the photo uploads---I am new at this.

Philips Mantel Radio
Philips Mantel Radio
Philips Mantel Radio
Philips Mantel Radio


 
 Return to top of page · Post #: 7 · Written at 8:22:58 PM on 29 September 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

So how is it this set (made in Great Britain) is not earthed. Did Australia have an earth-mains system before England? Surely not!

Earthing systems have almost always existed for power outlets, both in Australia and Great Britain. The problem here is that many appliances were not wired to take advantage of it. Lighting circuits in Australia were not required to be provided with earthing until the late 1970s or early 1980s. Fixed appliances such as a water heater or range were and are required to be earthed.

Don't try earthing a radio with a live chassis. You have a 50% chance of "blowing fuses" via such a radio forever more. It may also be deemed illegal as it would provide a second MEN (Multiple Earth Neutral) link in your dwelling. At your main switchboard the neutral and earth conductors are bonded together to create extra earthing integrity in the electrical supply. This is the only point at where such links may be provided however.

Earthing of receivers that are fitted with an isolating transformer is fine, and probably recommended.

As for the electrical supplies of these two great nations, they are very similar indeed. Britain didn't have it all her way though. With regard to many things, Australia tended to adopt the best of British and the best of American, blend those and benefit from the results. Australia does use the British 415/240V three phase, four wire electrical system for all standard extra-low voltage installations. Colours for hard wiring are red, white, blue, black and green/yellow for the three actives, neutral and earth respectively, though in old installations you may see red, yellow, blue, black and green. America supplied us, entirely by accident, with the pin layout for our general purpose outlets (power points). Whilst the US was deciding on what pin layout to standardise, we were doing the same thing. The US rejected the layout that is now known as the "Australian pattern" for one with two parallel pins (for 110V circuits) and Australia standardised with the pin pattern we have almost always had. Again, we added some British flavour to it by requiring the outlets to be individually switched.

That said, Australian appliances were still optionally being fitted with bayonet light socket plugs up to around 1950 for the benefit of those who didn't have many power points in their home. Typical homes would have had three or four power points at the most in those days.

You are quite correct that many homes don't have RCDs fitted. There are a lot of older homes that are still wired in VIR - the old cotton-covered cable that was installed in split-seam conduits for protection. At the Old Gladesville Hospital site there is still a Doctors Cottage there that is wired in VIR, has the original round Bakelite electrical fittings on cedar mounting blocks and also has working gasolier lamps on the walls. I doubt these were re-jetted when coal gas was replaced with natural gas in the 1980s though. This building remains abandoned more than 20 years after I worked at this hospital.

If you would like to have photos published in your comments, e-mail them to me as per Point 6 just above the comment field and I'll upload them for you.


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

 
 Return to top of page · Post #: 8 · Written at 11:34:40 PM on 30 September 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

Photos uploaded to Post 6.


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

 
 Return to top of page · Post #: 9 · Written at 12:33:26 AM on 1 October 2017.
Tallar Carl's avatar
 Location: Latham, ACT
 Member since 21 February 2015
 Member #: 1705
 Postcount: 1574

Omg what are those wire wound resistors like that for . They do not look correct.


 
 Return to top of page · Post #: 10 · Written at 1:12:31 AM on 1 October 2017.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6012

Transformerless sets were designed to be able to run from both AC and DC mains supplies. (Australia also had DC mains. There's a table of dates of conversion of states and regions to AC somewhere on this site)

Secondary benefits for the manufacturer were avoiding the expense of, and space occupied by, a power transformer.

There can be no earthing of transformerless sets if the chassis is used as a common "bus" which was usually the case with such sets. They needed to be carefully insulated, including sealing the hole containing the grub screws in knobs. Nowadays they are usually potential death traps, such as the one you have.


 
 Return to top of page · Post #: 11 · Written at 3:42:38 AM on 1 October 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

The resistors positioned that way does look unusual but if the set is AC/DC and was originally fitted with a back then anything can be expected, especially if there is a risk that the chassis and even pot shafts could be live under normal use.

Even if and when serviced and proven to be in working order I would not operate an AC/DC receiver without an isolating transformer.

When reading an article on Pyrmont Power Station tonight it mentioned that no new DC mains customers were connected in Sydney after 1935. After this, all loads had to either work from AC mains. Loads could still be configured to work from either system by leaving out the transformer, in the case of a radio or the use of a mercury-arc rectifier in the case of a lift or escalator or an industrial application such as a plating bath.


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

 
 Return to top of page · Post #: 12 · Written at 9:44:14 AM on 1 October 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

It seems like I have created some confusion here, so a little clarification:

a) The mains is NOT connected to the chassis. The mains is in series with the green enamel WW resistor and the valve heaters, as well as a PTC resistor.

b) The green WW resistor cracked and failed. The repairer fitted the mess of grey WW resistors, using the original green WW for support.

c) The green WW sagged and one of the grey WW resistors made contact with the chassis. Only then did the chassis become live.


 
 Return to top of page · Post #: 13 · Written at 10:09:30 AM on 1 October 2017.
Wa2ise's avatar
 Location: Oradell, US
 Member since 2 April 2010
 Member #: 643
 Postcount: 766

QUOTE: Colours for hard wiring are red, white, blue, black and green/yellow for the three actives, neutral and earth respectively


In the USA, white is neutral, and black is a hot wire. There is one exception for white being the neutral, if you have a "traveler" wire going to a wall switch and back (where there is nothing else in the box holding the switch) then the white at the switch is a hot wire.

Also in the USA, hot chassis radios evolved to have more user protection. At first, the chassis was wired directly (usually through a power switch) to one side of the mains powerline. The cabinet, being wood or bakelite, would insulate the chassis from the user. And knobs were also plastic like bakelite, and usually a cardboard back kept you away from the chassis. But pull off a knob and you have exposed powerline waiting to bite you. Later, they made the powerline be a B- bus, with a usually 0.1μF cap providing an RF ground to tie the chassis to the B_ line. Somewhat better, as the cap would limit shocking current. Later, the volume control and tuning would have plastic shafts. And more later on, the plastic knobs would be captive, in that you couldn't remove them from the plastic cabinet (sometimes if you removed the chassis you could twist the loose knobs enough to fit a keyhole slot to remove and lose them). This last essentially made the radio a fully enclosed (but with vent slots) plastic box that you could not touch any internal metal. We had long used internal loops or ferrite rod AM antennas, and no maker used long wires as antennas. Oh, we did have long wires, but every maker quit that pretty much before WW2.

Aussie makers could have used the power plug to mandate that the chassis was near ground earth potential, IF there was a polarization standard. \ / instead of | | Heard that there was no standard until sometime in the 1960's? And this also assumes electricians never wire powerpoints backwards.


 
 Return to top of page · Post #: 14 · Written at 6:22:46 PM on 1 October 2017.
BringBackTheValve's Gravatar
 Location: Linton, VIC
 Member since 30 December 2016
 Member #: 2028
 Postcount: 240

I WAS WRONG!

Correction on my last post, regarding chassis/mains isolation. Neutral is connected to chassis.

So yes, correct everyone, this set can easily become lethal with an incorrectly wired mains plug (or outlet, as Wa2ise pointed out)

It is AC only, draws 70 Watts, and since bending the WW resistors away from the speaker tranny I have been operating it with an earthed chassis.

I am not a sparky, I'm an electronics tech., so I do not know the legalities here. I love this set, best sensitivity I have ever come across, so I intend to restore it fully.

I intend to keep the chassis earthed, not only for protection, but it helps with performance, especially long distance reception.

I realise I have tied earth to neutral inside the appliance.

Question for sparkys: Is this OK with VIC regulations??

Many thanks,

G.


 
 Return to top of page · Post #: 15 · Written at 6:31:36 PM on 1 October 2017.
Brad's avatar
 Administrator
 Location: Greenwich, NSW
 Member since 15 November 2005
 Member #: 1
 Postcount: 6349

I intend to keep the chassis earthed, not only for protection, but it helps with performance, especially long distance reception.

I realise I have tied earth to neutral inside the appliance.


If you mean the neutral and earth from the mains cord is bridged inside the receiver then this is a bad practice, a very bad practice.

At the very least, if you plug the radio into an incorrectly wired GPO the circuit breaker will trip and may likely fail to reset because it'll start self-destructing in the milliseconds prior to it tripping.

It also breaches the deal with MEN links as I mentioned above. There will be an Australian Standard for appliance earthing though I do not know what the number is.

If you want some protection whilst using an AC/DC set you should use an isolation transformer instead of earthing the set. Most agree, however, that general use of these receivers isn't worth the risk and they usually end up as display items even after restoration.


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

 
« Back · 1 · 2 · Next »
 You need to be a member to post comments on this forum.

Sign In

Username:
Password:
 Keep me logged in.
Do not tick box on a computer with public access.