|
Vintage Radio (domestic) Domestic vintage radio (wireless) receivers only. |
|
Thread Tools |
17th Jan 2018, 12:28 am | #1 |
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.
|
17th Jan 2018, 12:36 am | #2 |
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 |
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 |
Dekatron
Join Date: Apr 2011
Location: Cornwall, UK.
Posts: 13,454
|
Re: Bush VTR103 capacitor type
Interesting circuit, chassis is B -ve.
Lawrence. |