ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
A little warning when you are replacing semiconductors in B&O products.
You can find a lot of B&O products 1960 -> 1980 where some semiconductors a "painted" on the top.
This means the parts is a selected type and NOT a standard.
Unfortunately B&O do not give much information of which parameter the selection is done, but I know it can be be noise, hFE, UCE as examples.
/Frede
I've noticed the same while repairing a Beomaster 4400 (see thread on the forum). If the part is marked with an asterisk (*) in the schematic, it's a "specially selected part". In my case, I noticed this at the long tailed pair. Ideally, you want high HFE, matched pairs there.