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Vintage Audio (record players, hi-fi etc) Amplifiers, speakers, gramophones and other audio equipment. |
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14th Jan 2021, 10:27 am | #41 | |
Tetrode
Join Date: Nov 2020
Location: London, UK.
Posts: 87
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Re: CCL Capacitor for Deccasound 600
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Thank you again. |
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14th Jan 2021, 10:41 am | #42 |
Dekatron
Join Date: Feb 2009
Location: Chesterfield, Derbyshire, UK.
Posts: 3,737
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Re: CCL Capacitor for Deccasound 600
Hi it looked like the choke was o/c from the start , but I missed a load of threads, it would be unusual for a low tension choke to go o/c they are wound with quite thick wire. It looks like it is going to be sorted with a competent person, good luck with it . Mick.
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14th Jan 2021, 1:09 pm | #43 |
Tetrode
Join Date: May 2014
Location: Bridgnorth, Shropshire, UK.
Posts: 51
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Re: CCL Capacitor for Deccasound 600
Well after following these threads it's like going back in time. I spent some very happy 20 odd years working in the Decca service dept at Bridgnorth working as technical support. In all those years I cannot recall one of these chokes going faulty in any way they were more or least used on all Decca audio products of a 6 Watt nature at that time. The transformers count those on one hand even the rectifier does not look original. So I still think the best advice is to strip back checking the mains Tx fitted is correct for the job and rewire back to spec. After a successful repair the end user will find he has got quite a nice sounding system even though it must be now some 40+ years old able to support a ceramic cartridge Decca used a Sonatone 9TA series which in its day was able to hold its head high . The speakers supplied by Decca were the L100 an 8ohm system which to my younger ears sounded quite good not having the colouration some units in plastic boxes have today Decca sold these items though as separates so the end user could choose an alternate deck and speakers hence the model no i.e. 6 meaning 6 Watt 0 series reference 4 of course there were 4 items and it did produce 6watts RMS per channel The amp had a mains output for a auxiliary source
Sorry if I have gone on a lot but it does bring back so many memories of things going right and wrong I still have a great many Decca manuals I retained when I left Decca the company selling out to Tatung . I will make some arrangement for them to be either copied or given to an organisation that will look after them some of them don't appear even on this site. |
14th Jan 2021, 4:02 pm | #44 | |
Moderator
Join Date: Feb 2006
Location: Wembley, Middlesex
Posts: 7,219
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Re: CCL Capacitor for Deccasound 600
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I can get a 20V 20VA transformer which should be sufficient to power the modules and the pre-amp. One could easily change the lamp to a 24V type. You are unlikely to get a new choke, which means either having it rewound, fitting a resistor of say 47 ohms, or leaving it out altogether and increasing the reservoir capacitor. You will probably find that back in the days when these were manufactured, the rectifiers couldn't handle large inrush currents, so the smoothing caps were limited in size. Today one could fit say an 8A rectifier and a 6800uF capacitor which would probably give the same or better ripple. However this is only speculation until we can work out exactly what has failed and possibly why. |
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15th Jan 2021, 10:42 am | #45 |
Tetrode
Join Date: Nov 2020
Location: London, UK.
Posts: 87
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Re: CCL Capacitor for Deccasound 600
I'll have a look over weekend, take some measurements and update you. If it's something complicated for me, I'll ask for help for sure.
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15th Jan 2021, 7:47 pm | #46 |
Tetrode
Join Date: Nov 2020
Location: London, UK.
Posts: 87
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Re: CCL Capacitor for Deccasound 600
Hi everybody,
Firstly, I've found what's wrong with the circuit. Cable which comes to HT fuse was not soldered. I've soldered it and managed to get sound from one channel. I have loud hum even when nothing is connected. (from transformer maybe?) If I connect speaker to fine channel hum increases, if I connect other channel hum level is same. But unfortunately, while I move it upside down to bring it normal position, I've lost the sound, there is just loud hum now. (I think I've touch volume knob while I moving it. So it's better to look for professional solution. I'll send private messages. Thanks for all your help, at least I'm learning something. Fatih When I moved it upside down to bring it to a normal position |