Vintage Products

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 17:56:43 GMT

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 ikea

Re: Beolit 707 sounds terrible

tournedos — Fri, 30 Jan 2009 13:39:25 GMT

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.

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 13:33:23 GMT

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

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 13:26:51 GMT

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

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

Re: Beolit 707 sounds terrible

Stonk — Fri, 30 Jan 2009 13:23:55 GMT

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

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 13:21:16 GMT

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

Re: Beolit 707 sounds terrible

tournedos — Fri, 30 Jan 2009 13:20:27 GMT

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

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...

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 13:11:34 GMT

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

Re: Beolit 707 sounds terrible

tournedos — Fri, 30 Jan 2009 13:09:31 GMT

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!

Re: Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 13:05:27 GMT

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

Re: Beolit 707 sounds terrible

Stonk — Fri, 30 Jan 2009 13:05:16 GMT

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?

Re: Beolit 707 sounds terrible

Peter — Fri, 30 Jan 2009 12:50:45 GMT

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.

Beolit 707 sounds terrible

tomsloat — Fri, 30 Jan 2009 12:43:51 GMT

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