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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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17th Oct 2019, 6:42 pm | #21 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,883
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Re: Bush AC11 - Newbie Project
The Trader Service Sheet 951 values and your measured values agree, I don’t know about the Bush service sheet. From your pictures, plus your readings, I would suggest the transformer is ok.
Enjoy your restoration project. Cheers John |
17th Oct 2019, 7:07 pm | #22 |
Dekatron
Join Date: Oct 2003
Location: Croydon, Surrey, UK.
Posts: 7,567
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Re: Bush AC11 - Newbie Project
Don't worry too much about mains transformer (or any transformer for that matter) DC resistances. The values given are only a guide but if you think about it, you only need one turn to go short circuit and it wouldn't make any difference to the reading you get BUT the transformer would not work....it would overheat rapidly and probably fail spectacularly if not disconnected pretty quickly. If the radio is working, the transformer is OK. Replacing the leaky old waxies will reduce HT current possibly by quite a few milliamps and will certainly help to prolong the life of the mains and output transformers.
If the DC reading is wildly out then obviously that would be cause for concern but 10 or even 20 ohms or more doesn't mean there is a fault.
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17th Oct 2019, 9:11 pm | #23 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,383
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Re: Bush AC11 - Newbie Project
Thanks for the close-ups of the transformer. Photo #3 doesn't look good, with evidence of charring and so it's obviously been very hot at some point. It is quite possible that you might have some shorted turns. If so it will start to smoke again soon after you apply power. Try powering up without the rectifier fitted and do some voltage checks on the secondary windings. If the transformer is getting hot off-load you will soon smell it. Cheers, Jerry
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18th Oct 2019, 4:15 pm | #24 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
So, taking out V5 (Trader Sheet) leaves just the mains comming into the set connecting to the transformer and everything else out of circuit. A nice easy test. Presumably I can measure the AC voltages at the secondary side (being careful) to see what kind of range they are in.
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18th Oct 2019, 4:37 pm | #25 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,383
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Re: Bush AC11 - Newbie Project
That's right. You'll need a multimeter on the AC volts range capable of at least 250v. If the max secondary voltage is around 200v AC that's a good sign but keep a lookout (and sniff out) for transformer burning. If you see or smell smoke then turn off power immediately. Don't leave it running for any length of time unattended.
If, as I suspect, there is a winding short then option 1 is you'll need a replacement transformer. These sets are fairly common so if you post a request in the parts wanted section you might find somebody with a scrap set willing to salvage the mains transformer for you. Second option is to get it rewound and Ed Dinning on this Forum can probably do it for you for a fee. However, let's do the power test first. Be careful removing the rectifier (and any of the other valves). Some have a metal skirt which isn't a problem but the ones with a moulded glass base are held in place by a small glass pip that slips behind a metal wire spring on the valveholder. If you yank out the valve it is easy to shear off the glass pip and the valve then loses vacuum and is useless. Take care and release the wire spring first if poss. Cheers, Jerry Last edited by cathoderay57; 18th Oct 2019 at 4:45 pm. |
18th Oct 2019, 8:18 pm | #26 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,883
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Re: Bush AC11 - Newbie Project
In your first post #1 you said when you first switched on it worked for a short time before fading and only a buzz, did you detect a suspicious smell or any smoke? Did you notice any wax near the Mains transformer or in the cabinet, when you were taking the pictures?
Cheers John |
1st Nov 2019, 2:06 pm | #27 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Managed to find some time to play radios again...
When I switched it on previously there were no burning smells. I've removed recifier valve - moving the retaining spring out of the way first. I switched the set and on and kept a close eye on the transformer - no smoke or anything else I'm pleased to say (though I still don't like the look of the transformer). I've measured the AC Voltage at the taps on the secondary side of the mains transformer - see attached. Voltage comapres quite well to Bush service sheets (no load): Scale 10V - Mine 10V Heater 130 - Mine 127V HT 285 - Mine 270V |
1st Nov 2019, 3:43 pm | #28 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
I'm guessing the wheel in the attached photo is some kind of flywheel. It currently is loose on the tuning shaft despite there being two screws that could secure it. Am I right in thinking that this has become loose and I should just tighten the screws?
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1st Nov 2019, 4:25 pm | #29 |
Dekatron
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,535
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Re: Bush AC11 - Newbie Project
Yes, the two screws to lock it to the shaft can just be tightened.
The flywheel is simply there to give a nice feel to the tuning and it also allows for quick "spin and freewheel" end to end tuning, though it's not a good idea to get too enthusiastic and let things run hard into the endstops!
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1st Nov 2019, 4:28 pm | #30 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Thanks, screws tightened now
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3rd Nov 2019, 8:19 pm | #31 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Knobs Cleaned & felt spacers washed.
New bulbs fitted for tunning dial Refitted the rectifier valve & started her up heaters glowed and after a short while I managed to get Absolute Radio (I've learnt something;-) ). Sound is a bit poppy and cracakly but its kind of working. Dial glowing nicely. No burning or smells from the transformer (though it still looks a bit sad). I think there is more work to do here but at least there is progress... |
4th Nov 2019, 11:21 am | #32 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,883
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Re: Bush AC11 - Newbie Project
Glad you making progress, I was wondering what aerial are you using?
Cheers John |
4th Nov 2019, 7:48 pm | #33 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Stock internal loop aerial only.
I remember you said you could run it outside of the cabinet it you made your own and used and extension lead ofr the o/p tx. I was wondering how you get the plugs/sockets to make an extension lead ? |
4th Nov 2019, 8:32 pm | #34 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,883
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Re: Bush AC11 - Newbie Project
I had some from an old scrap chassis, AC34, so I removed all the useful parts, the cabinet was badly damaged and full of woodworm so I binned it.
Cheers John |
5th Nov 2019, 9:39 pm | #35 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Ah right - that makes a lot of sense
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30th Nov 2019, 3:31 pm | #36 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
Not found much time to work on the radio recently but had clean up the knobs and felt washers - see photo. I never rememer them having coloured lettering but tempted to dowomething subtle with them... Any recommendations?
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30th Nov 2019, 6:16 pm | #37 |
Nonode
Join Date: Oct 2017
Location: Bristol, UK.
Posts: 2,383
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Re: Bush AC11 - Newbie Project
Here are some ideas https://www.vintage-radio.net/forum/...read.php?t=781 Cheers, Jerry
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30th Nov 2019, 7:13 pm | #38 |
Nonode
Join Date: Nov 2016
Location: Aberaeron, Ceredigion, Wales, UK.
Posts: 2,883
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Re: Bush AC11 - Newbie Project
If you follow the advice,which Jerry attached, you will get good results. I simply used a very fine art brush and white acrylic paint, that’s all I had, and filled in, then whiped away the surplus.
John |
3rd Dec 2019, 6:42 pm | #39 |
Triode
Join Date: Jul 2017
Location: Bridgend, Glamorgan, Wales, UK.
Posts: 44
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Re: Bush AC11 - Newbie Project
With mine i got a metalised gold paint pen filled in where the lettering is and wiped off the excess with great results
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27th Dec 2019, 2:29 pm | #40 |
Triode
Join Date: Sep 2019
Location: Chelmsford, Essex, UK.
Posts: 30
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Re: Bush AC11 - Newbie Project
So not done the lettering next but have got some other progress done:
Radio sounding better now and to my delight the secnd track played in the radio was "Comfortably Numb" - excellent result. I think there is a bit more work to do here ;-) Last edited by RetroGuy527; 27th Dec 2019 at 2:34 pm. Reason: (photos attached) |