11-98 transformer
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 414
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No valves lit up or anything
Did you check the 6 volt winding on the transformer, will be pins 4 and 5 on the 6V4?
Pin 3 is the cathode, if it is open circuit, there will be no HT anywhere, so that may be your only problem.
Harold
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Location: Belrose, NSW
Member since 31 December 2015
Member #: 1844
Postcount: 2520
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The socket has unused contact tags in it. One of those can be moved to Pin 3. There is no need to replace the whole socket.
Just pick an unused tag, squeeze the tag firmly near the insulator with a pair of long-nose pliers, and push it out the top.
Fit it in place of the damaged one and give the locking tab a stab with a jeweller's screwdriver. Then solder its wire back on.
Old servicing trick!
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 414
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Your question prompted a fair bit of discussion, how did you get on?
Was the transformer OK and were you able to fix the rectifier socket?
Harold
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5459
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You can if the socket is a write off, drill out rivets. However, anything like that I prefer to do with the tubes out. If you are going to buy in a new socket, I prefer Ceramic ones on rectifiers & output tubes as most damage to the Bakelite fibre ones is caused by heat, tracking and overloads.
I would concur with Harold: One does like to see operational dial lights & heaters. A faulty AWA dial light socket was reported recently and I had one of the same do the same thing. This does not come under unusual faults, I have also had a HMV / Marconi and a Breville, Kriesler plastic, and a 5Y3 with socket and wiring shorts.
Marc
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Location: Newcastle, NSW
Member since 6 June 2020
Member #: 2422
Postcount: 19
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Hi All,
Sorry been in hospital. Not electrocuted some mystery rheumatoid thingy.
I replaced the socket. Easy enough to do
Still no lights, but I haven't checked the globe.
I have 280 volts on pin 1 and pin 7 on 6V4 so that part of the transformer is ok.
I had a spare 6V4 but the readings are the same for both.
Pin 4 drops from 3.7 down to .7 quickly and stays there.
There is no power on any of the other test points.
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6797
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Pin 4 drops from 3.7 down to .7 quickly and stays there.
6.3 volt winding or heater circuit shorted? Is the transformer humming and/or getting hot?
There is no power on any of the other test points.
Do you mean other valve heater connection points?
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Location: Newcastle, NSW
Member since 6 June 2020
Member #: 2422
Postcount: 19
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So there is no power at the light socket
is that where I should get 6 volts?
Thanks all
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 414
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Yes, you should see 6V at the dial lamp.
Can you go back to where the 6V winding wires come out of the transformer and see if there is voltage there? If not, then unsolder the 6V lead and see if there is voltage at the transformer. If yes, there is either a short or a break in the wiring. If no, and you are getting the high voltage correctly, then the transformer is suspect.
You didn't, by chance, have your meter on DC volts?
Harold
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5459
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Getting AC & DC mixed up is quite common. It is critical to know the difference & where it is liable to be.
There is a recent post where two of us repairing the same model radio both had shorted globe sockets, fortunately I had seen the burnt wire & did comment to the owner at the time, we examined it that that looked sus and it was.
One must be careful with soldering. Leaving tails and large blobs of solder can lead to shorting. Failing to check for debris prior to start up, is another methodology fail.
I did have an Astor RK, where I recovered pretty much a packet of needles, one of which destroyed the rectifier. Tubes do go heater to cathode short. Often that can be picked up by a common ohmmeter.
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Location: Newcastle, NSW
Member since 6 June 2020
Member #: 2422
Postcount: 19
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Hi All,
Yes I had my meter on AC.
Is there a diagram of the transformer anywhere?
There are no markings on the transformer that I can see.
I will track it back from the light socket.
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Location: Newcastle, NSW
Member since 6 June 2020
Member #: 2422
Postcount: 19
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So I have 8 volts with the wire removed and a dead short between pins 4 and 5 on 6V4 and earth.
So this could be my problem?
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Location: Cameron Park, NSW
Member since 5 November 2010
Member #: 770
Postcount: 414
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Pin 4 or 5 is connected to earth so measuring from the pin to earth will show as a short.
With all valves and dial globes removed and the transformer wire disconnected, what resistance do you measure between pins 4 and 5 on the 6V4 socket? If this is still a short your problem lies in the heater/dial lamp wiring. Look for solder blobs or valve socket pins touching adjacent pins.
Your transformer seems to be OK.
Harold
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Location: Sydney, NSW
Member since 28 January 2011
Member #: 823
Postcount: 6797
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Do they have to be drilled out. Looks like its riveted in.
Yes.
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Location: Wangaratta, VIC
Member since 21 February 2009
Member #: 438
Postcount: 5459
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The rivets have to be drilled out. As before no tubes in place its then a case of 1/8" blind rivets if you have the apparatus, or 2.5mm screw (metal threads) are gettable, as are most sizes like 3mm.
With hot tubes like rectifiers I use ceramic types.
Marc
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Location: Newcastle, NSW
Member since 6 June 2020
Member #: 2422
Postcount: 19
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Ok, With all lights and valve out the short is gone.
Replacing the valves one by one shows the short back on all the valves.
Could they all be short? I don't have a valve tester.
I did find one solder blob, I think between pins 3 and 4 of 6V4.
How should the lights be connected? At the moment they are connected in series, which makes sense. But I haven't changed them so I don't think it affects the problem.
Thanks
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