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ARCHIVED FORUM -- April 2007 to March 2012
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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 01-30-2009 5:56 PM by tomsloat. 12 replies.
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  • 01-30-2009 12:43 PM

    Beolit 707 sounds terrible

    hi all just wonderd if i could draw on you'r experiance of these little radios. i received one today from ebay and it sounds awful there is no specific fault with the sound it's just not nice

    i read some where there are adjustments that can be done on this unit does anyone know what these are. the radio is complete and in otherwise good condition so i'd like to get it sounding nice.

    do these suffer from the usual capacitor problems?

    many thanks

    tom

  • 01-30-2009 12:50 PM In reply to

    Re: Beolit 707 sounds terrible

    Could well be the actual speaker - if you move the cone when the radio is off, does it sound coarse? It should move relatively easily and with no sticking.If it does seem to stick, the sound can be very poor. This would mean having the speaker rebuilt as drive units are very difficult to find. It should have a warm and full sound when working.

  • 01-30-2009 1:05 PM In reply to

    • Stonk
    • Top 50 Contributor
    • Joined on 04-16-2007
    • Marlow, Bucks, UK
    • Posts 1,688
    • Founder

    Re: Beolit 707 sounds terrible

    I agree with Peter. The speaker problem is very common as they tend to get 'stuck' losing all the bass. Can you describe the sound? Does the sound differ between FM & MW?

     

     

                                                                                                  

    If you think nobody cares, try missing a couple of payments.

  • 01-30-2009 1:05 PM In reply to

    Re: Beolit 707 sounds terrible

    hi peter the speaker feels free enough there is no noise i can hear (just ran to the kitchen and gave it a poke ) it sounds reasonable untill there is any bass which ruins the sound but it does not sound like normal distortion more like it's running out of power

    thanks for the reply

    tom

  • 01-30-2009 1:09 PM In reply to

    Re: Beolit 707 sounds terrible

    I have two of these and both seem to have problems in the presence of strong signals (not necessarily the one you are trying to tune in). So as silly as it seems, try with the antenna down if you haven't already!

    -mika

  • 01-30-2009 1:11 PM In reply to

    Re: Beolit 707 sounds terrible

    hi stonk thanks for the reply

     just tried the speaker again it moves freely without noise . to describe the sound it sounds like the bass is distorting at any volume doesent get any worse with volume untill i get to silly levels

    i noticed some of the little red electrolictic capacitors on the card could these be dead

    thanks

    tom

  • 01-30-2009 1:20 PM In reply to

    Re: Beolit 707 sounds terrible

    One more idea - if you have a suitable source, try connecting something to the tape input and use the radio as an amplifier (press both FM & MW down to select the function). If the problem persists, we can then rule out the radio part as the source of the problem. The amp part will probably be much easier to fix, then we will just have to wait for Dillen to tell us what part usually fails Laughing

    Come to think of it, Beolits have an external speaker connection as well - try some other speaker if you have one available! If the sound still distorts, at least your Beolit speaker is probably all right...

    -mika

  • 01-30-2009 1:21 PM In reply to

    Re: Beolit 707 sounds terrible

    i read somewhere that someone measured the Quiescent current and centre point voltage this is forigen to me but i have a meter and a love of twiddling  does this make any sense to anyone?

    thanks

     

  • 01-30-2009 1:23 PM In reply to

    • Stonk
    • Top 50 Contributor
    • Joined on 04-16-2007
    • Marlow, Bucks, UK
    • Posts 1,688
    • Founder

    Re: Beolit 707 sounds terrible

    Tom,

    I'm afraid my electronic tech knowledge leans more towards the hit or miss side. However, I have repaired various Beolits and have found a few with dry joint problems. Worth checking that out. The speaker can't be ruled out still and if you're on the right side of London near me you are welcome to bring it over to try it with a good one that I have here.

    Capacitors certainly can't be ruled out too. do any look like they've leaked or discoloured?

    Steve

                                                                                                  

    If you think nobody cares, try missing a couple of payments.

  • 01-30-2009 1:26 PM In reply to

    Re: Beolit 707 sounds terrible

    tournedos:
    One more idea - if you have a suitable source, try connecting something to the tape input and use the radio as an amplifier (press both FM & MW down to select the function). If the problem persists, we can then rule out the radio part as the source of the problem. The amp part will probably be much easier to fix, then we will just have to wait for Dillen to tell us what part usually fails Laughing

    hi tried this and sounds the same but quiet (with bleed from the radio) so probably the amp section at fault

    thanks for the input

  • 01-30-2009 1:33 PM In reply to

    Re: Beolit 707 sounds terrible

    Stonk:

    Tom,

    I'm afraid my electronic tech knowledge leans more towards the hit or miss side. However, I have repaired various Beolits and have found a few with dry joint problems. Worth checking that out. The speaker can't be ruled out still and if you're on the right side of London near me you are welcome to bring it over to try it with a good one that I have here.

    Capacitors certainly can't be ruled out too. do any look like they've leaked or discoloured?

    Steve

     

    thanks steve i will look for dry joints i'm in bromley would love to hear one that works properly to compare i dont know if i'm expecting to much of it

  • 01-30-2009 1:39 PM In reply to

    Re: Beolit 707 sounds terrible

    tomsloat:

    hi tried this and sounds the same but quiet (with bleed from the radio) so probably the amp section at fault

    OK, I guess we better wait for the experts before getting further... I can only give general ideas; the amp stage certainly has a quiescent current (or idle current) setting as well as a midpoint voltage setting, and those might cause this. The same looking trimpots are known to go bad in many 70s-80s B&O kit.

    The power amp seems to use two germanium transistors (ACsomething) and those sometimes fail partly, i.e they work but just not according to the spec, and cause curious faults.

    -mika

  • 01-30-2009 5:56 PM In reply to

    Re: Beolit 707 sounds terrible

    thanks everyone for the help so far. looks like i'll need to gas up the soldering iron and get some parts

    tom

    sorry for delay got dragged to ikeaWink

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