Bush TUG24. Buzzing on sound. - UK Vintage Radio Repair and Restoration Discussion Forum

FERNSEH · 22nd Sep 2015, 11:24 pm

Just two minor jobs to to a Bush TUG24 and then it can be returned to it's owner.
First is the slight damage to the top left corner of the cabinet, see the attachment.
The other fault that has manifested itself since the set was serviced earlier this year is a buzzing on the sound, also loss of interlace. This will be almost certainly be the decoupling electolytic capacitor in the HT supply to the RF deck. It is located on the main deck.

DFWB.

Heatercathodeshort · 23rd Sep 2015, 7:21 am

Quote:

Originally Posted by FERNSEH

First is the slight damage to the top left corner of the cabinet, see the attachment.DFWB.

That damage appears to have been carried out by Jerry. I think you may require the services of Tom..J.

FERNSEH · 23rd Sep 2015, 1:18 pm

Hi John,
Tom doesn't do this job, it's up to me to do it.

Sure enough there is a 10 volt P - P 50hz ripple on the receiver section HT supply. Connect a 15mfd elco between the HT line and chassis and the buzzing dissappears. Also an improvement to the picture and interlace.
The scope probe was connected to the B5 plug on the main deck.

DFWB.

beery · 23rd Sep 2015, 4:26 pm

Hi David,
I've usually found the main resivoir capacitors (C61 & C62 on Trader sheet 1003) to be very reliable. However I've never had much luck trying to re-form the single 16uF cap (C63).
The giant waxy 0.75uF cap (C60) is also key to removing the ripple. I don't know of any other make of set that uses a capacitor in this way as a sort of anti phase ripple injector (anti to the phase shift in L24).

I used to have some 1990s manufactured dual caps that are a suitable replacement for C61 and C62. I will have to have a look next time I visit my parents place.

Cheers
Andy

22nd Sep 2015, 11:24 pm	#1
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Bush TUG24. Buzzing on sound. Just two minor jobs to to a Bush TUG24 and then it can be returned to it's owner. First is the slight damage to the top left corner of the cabinet, see the attachment. The other fault that has manifested itself since the set was serviced earlier this year is a buzzing on the sound, also loss of interlace. This will be almost certainly be the decoupling electolytic capacitor in the HT supply to the RF deck. It is located on the main deck. DFWB. Attached Thumbnails

23rd Sep 2015, 1:18 pm	#3
FERNSEH Dekatron Join Date: Mar 2005 Location: Gateshead, Tyne and Wear, UK. Posts: 7,444	Re: Bush TUG24. Buzzing on sound. Hi John, Tom doesn't do this job, it's up to me to do it. Sure enough there is a 10 volt P - P 50hz ripple on the receiver section HT supply. Connect a 15mfd elco between the HT line and chassis and the buzzing dissappears. Also an improvement to the picture and interlace. The scope probe was connected to the B5 plug on the main deck. DFWB. Attached Thumbnails

23rd Sep 2015, 4:26 pm	#4
beery Heptode Join Date: Jun 2006 Location: Ware, Hertfordshire, UK. Posts: 988	Re: Bush TUG24. Buzzing on sound. Hi David, I've usually found the main resivoir capacitors (C61 & C62 on Trader sheet 1003) to be very reliable. However I've never had much luck trying to re-form the single 16uF cap (C63). The giant waxy 0.75uF cap (C60) is also key to removing the ripple. I don't know of any other make of set that uses a capacitor in this way as a sort of anti phase ripple injector (anti to the phase shift in L24). I used to have some 1990s manufactured dual caps that are a suitable replacement for C61 and C62. I will have to have a look next time I visit my parents place. Cheers Andy __________________ www.youtube.com/user/andyvalve100