Bush VTR103 capacitor type - UK Vintage Radio Repair and Restoration Discussion Forum

tim.norris · 17th Jan 2018, 12:28 am

I have been looking at a Bush VTR103, which was not working. Have got it going by swapping out the AF116 transistors for AF126. It works well apart from a bad case of excessive sibilance on FM. Looking through some old threads, C46 in the ratio detector circuit could be a culprit as well as the OA79 diodes, which check out fine, but the capacitor looks a bit of an oddball. 8uf, 6volts working but it looks like a ceramic type? Would it be OK to swap with the nearest value 10uf electrolytic? Also according to the circuit the positive end goes to chassis. Or should I try changing the red and yellow Plesseys first? all help appreciated. Regards, Tim.

Refugee · 17th Jan 2018, 12:36 am

That looks like an albino RS electrolytic from the 1960s.
The RS branded ones were usually grey.
A modern 10uf will do if you done order an 8uf as a special.

Boater Sam · 17th Jan 2018, 7:33 am

+ to chassis is correct - this time! 5uf to 10uf should be fine, the tolerance on electrolytics is wide anyway.
Sibilance on FM can also be due to alignment errors, if all else fails check it.

ms660 · 17th Jan 2018, 2:14 pm

Interesting circuit, chassis is B -ve.

Lawrence.

17th Jan 2018, 12:28 am	#1
tim.norris Hexode Join Date: Feb 2012 Location: Blackburn, Lancashire, UK. Posts: 282	Bush VTR103 capacitor type I have been looking at a Bush VTR103, which was not working. Have got it going by swapping out the AF116 transistors for AF126. It works well apart from a bad case of excessive sibilance on FM. Looking through some old threads, C46 in the ratio detector circuit could be a culprit as well as the OA79 diodes, which check out fine, but the capacitor looks a bit of an oddball. 8uf, 6volts working but it looks like a ceramic type? Would it be OK to swap with the nearest value 10uf electrolytic? Also according to the circuit the positive end goes to chassis. Or should I try changing the red and yellow Plesseys first? all help appreciated. Regards, Tim. Attached Thumbnails

17th Jan 2018, 12:36 am	#2
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Bush VTR103 capacitor type That looks like an albino RS electrolytic from the 1960s. The RS branded ones were usually grey. A modern 10uf will do if you done order an 8uf as a special.

17th Jan 2018, 7:33 am	#3
Boater Sam Banned Join Date: Dec 2013 Location: Middlewich, Cheshire, UK. & Winter in the Philippines. Posts: 3,897	Re: Bush VTR103 capacitor type + to chassis is correct - this time! 5uf to 10uf should be fine, the tolerance on electrolytics is wide anyway. Sibilance on FM can also be due to alignment errors, if all else fails check it.

17th Jan 2018, 2:14 pm	#4
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Bush VTR103 capacitor type Interesting circuit, chassis is B -ve. Lawrence.