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Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
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19th Feb 2023, 1:45 am | #1 |
Hexode
Join Date: Sep 2010
Location: Stourbridge, West Midlands, UK.
Posts: 434
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Beolit 600 No FM
Hello, I came by a nice condition Beolit 600 radio today which I obtained for just £25! It works very well on MW/LW but FM is silent, I cleaned the wave change switches with servisol as they were noisy but still no FM, I'm not too familiar with these sets, so I'm asking if someone with B&O knowledge could point me in the right direction as there seems no obvious reason for the dead FM.
It's the slimline Beolit 600 from the early 70s. |
19th Feb 2023, 10:29 am | #2 |
Octode
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,731
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Re: Beolit 600 No FM
I have repaired a number of these sets. Can you confirm exactly which model it is though, as there were a few model 600's, and the circuits are somewhat different. I can probably picture your set, (slim, black with metal dial and controls on the top) but my circuits don't indicate which. Beolit usually included a schematic in a small envelope stuck to the inside of the set. Do you have it? What 'TR' number is that showing?
Generically, you need to check the voltages on the FM front end transistors. The transistors themselves are probably fine, but you may be missing a power supply to them. |
19th Feb 2023, 2:38 pm | #3 |
Hexode
Join Date: Sep 2010
Location: Stourbridge, West Midlands, UK.
Posts: 434
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Re: Beolit 600 No FM
Type 1501 is showing on the schematic.
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19th Feb 2023, 3:23 pm | #4 |
Octode
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,731
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Re: Beolit 600 No FM
Ah, so this is the one with the separate FM module? Check for the 5.8V rail going into the module. I have had this reading very low, usually due to the wavechange switches still not making good contact, but also due to a very bad dry joint on the coil between the switch and module. From memory, the module will cease to work if the voltage has dropped below 4.5V.
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19th Feb 2023, 3:32 pm | #5 |
Dekatron
Join Date: Dec 2004
Location: East Yorkshire, UK.
Posts: 3,958
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Re: Beolit 600 No FM
I have the Beolit 700, I think it may be very similar to your 600. Mine had a wood shaving strategically placed in the wave change switch to make FM work. I would double check the contacts.
Just seen the above post, re W/C switch. BTW £25 for a Beolit, you have done very well. One hard to find part is the loudspeaker, but you have been lucky there. John.
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My favourite text message "I'll be there in five minutes, if not read again" Last edited by 60 oldjohn; 19th Feb 2023 at 3:38 pm. Reason: Added two comments. |
19th Feb 2023, 5:58 pm | #6 |
Hexode
Join Date: Sep 2010
Location: Stourbridge, West Midlands, UK.
Posts: 434
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Re: Beolit 600 No FM
I've got a fresh set of batteries in giving 7.7v, the set is drawing 18ma on MW/LW and 19ma on FM, I have measured 6.7v entering the FM module, the schematic is showing 5.8v on wire orange.
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19th Feb 2023, 6:34 pm | #7 |
Octode
Join Date: Sep 2020
Location: Thetford, Norfolk, UK.
Posts: 1,731
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Re: Beolit 600 No FM
It sounds like the FM module is not operating, as that voltage seems a bit high to me. Have you tested TR1 and TR2? And do you have a signal generator? Would be nice to feed 10.7Mhz into the IF strip to eliminate it.
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