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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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17th Jun 2021, 9:04 pm | #1 |
Heptode
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GEC BC402 receiver.
I am very much a novice so I need help I have the above radio and I think the smoothing capacitor has gone on this model it has four connections and it is 50uf+50uf +50uf 275v could any one tell me where I could get hold of one of these please.
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18th Jun 2021, 10:20 am | #2 |
Dekatron
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Re: Gec bc402
Wrong thread? This one is for giving info on where sets and parts can be found AFAIK.
Anyway, you may not find any exact drop in replacement but you may be able to gut and restuff the can with four suitable modern 47uF parts or if function takes priority over form you could simply use four individual capacitors under the chassis leaving the (disconnected) original in place for appearance sake.
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18th Jun 2021, 10:58 am | #3 |
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Re: Gec bc402
What makes you think the cap has failed? Is it hum?.
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18th Jun 2021, 11:01 am | #4 |
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Re: Gec bc402
It is a valve radio. All valves light up but absolutely no sound at all. I think the output transformer is ok
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18th Jun 2021, 11:24 am | #5 |
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Re: Gec bc402
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18th Jun 2021, 11:27 am | #6 | |
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Re: Gec bc402
Quote:
Voltage checks are the key point here. Tell us what you have measured otherwise we are all guessing. Triple 50uF caps are still available from specialist suppliers but they are not cheap. You don't want to change on guesswork just because you think it might be faulty. Most times, they would fail O/C and cause a very loud hum.
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18th Jun 2021, 11:36 am | #7 |
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Re: Gec bc402
Wrong section anyways for parts needed info.
Lawrence. |
18th Jun 2021, 11:37 am | #8 |
Heptode
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Re: Gec bc402
When I connect my multy meter to the input terminals on the output transformer I get a crackle noise in speaker. So I assume it is OK. I have replaced all valves with good ones apart from that I don't now where to go I am a novice I assumed then it was the smoothing capacitor =
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18th Jun 2021, 11:42 am | #9 |
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Re: Gec bc402
Certainly not smoothing cap at this point. Needs basic checks for starters. Just take care, lethal voltages.
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18th Jun 2021, 11:45 am | #10 | |
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Re: Gec bc402
Quote:
Lawrence. |
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18th Jun 2021, 1:18 pm | #11 |
Heptode
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Re: Gec bc402
Voltage on pin3 is 547 to 577
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18th Jun 2021, 1:23 pm | #12 |
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Re: Gec bc402
Sounds a bit high even without a load, if for instance a feed res was o/c.
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18th Jun 2021, 1:24 pm | #13 |
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Re: Gec bc402
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18th Jun 2021, 1:27 pm | #14 |
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Re: Gec bc402
Check what is on either side R36 and if needed the circuit is at the top of this page RHS.
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18th Jun 2021, 1:47 pm | #15 |
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Re: Gec bc402
477 voltage on pin 3 DC
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18th Jun 2021, 1:52 pm | #16 |
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Re: Gec bc402
R36 reads 560 one end 580 other dcv
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18th Jun 2021, 1:58 pm | #17 |
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Re: Gec bc402
I think I've got R36 wrong I have 2 service sheets for this model and R36 is different on both is R36 according to you on smoothing capacitor or on dropper please
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18th Jun 2021, 4:40 pm | #18 |
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Re: Gec bc402
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18th Jun 2021, 7:30 pm | #19 | |
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Re: Gec bc402
Quote:
You'll need to do some more voltage checks. I'm not trying to be unhelpful but the only way to learn, is by doing and looking at the circuit. Clue...the radio needs a LOT more than 48 volts HT to operate. So what does it say on the circuit? Your move..... I'm looking at the Trader sheet and there is a table showing all voltages.
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18th Jun 2021, 8:10 pm | #20 |
Heptode
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Re: Gec bc402
I am very grateful for your help. I will start again tomorrow. And re check if I am reading things correctly and let you now when I get some decent results
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