Hi all, I am in need of a bit of advice with transistor substitutions in AU-9900. Mine is in need of repair, having issues with unstable bias and slight distortion in one channel. I was thinking of replacing the usual suspect transistors on the driver board (F-2583) as it still has original transistors there which might be giving up their ghosts now... I have prepared a list of transistor replacements primary based on this extrmely helpful substitution list here: http://audiokarma.org/forums/index.php?threads/once-more-sansui-transistor-substitutions.583009/ But I have also noticed some alternative transistor substitutes being mentioned here and there, so I just wanted to get it reviewed by the experts and experienced people here to make sure I have got the replacements right (e.g. based on the location and usage on the particular board) For the F-2583 driver board, I have the following: Tr01, Tr02, Tr03, Tr04 2SA726 KSA992FA Tr05, Tr06 2SC1628 KSC3503 Tr07, T708 2SA818 KSA1381 Tr11, Tr12 2SC735 BC33716 Tr13, Tr14 2SA562 BC32716 Tr15, Tr16 2SC1124 KSC2690AYSTU Tr17, Tr18 2SA706 KSA1381ESTU Tr19, Tr20 2SD382 MJE15030G Tr21, Tr22 2SB537 MJE15031G Does this list look Ok? For easy reference, I have marked the replacements based on the position on the board, Please see this image here: I am also a bit confused with the Transistor list given in the service manual for F-2583, in particular for Tr05/06 and Tr07/08. The list has 2 different transistors printed for both set of positions, grouped by a big curly brace e.g for Tr05/06 both 2SC1124 and 2SC1628 are given (see image below). However, on the schematics Tr05/06 are given as 2SC1628. Similarly, Tr07/08 are given as 2SA818 only. And lastly, I may also need replacement Molex socket connectors for the driver board. Whoever serviced it before decided to solder the wires directly into the pins! I have searched and found this post here with a suggestion - http://audiokarma.org/forums/index.php?threads/au-9900-pcb-connector-blocks.398717/#post-9626896 Is the pitch value of 5.08mm right for F-2583 as well? If anyone has replaced or fixed the sockets on this board, any suggestions or tips would be very helpful. Thanks guys. Really appreciate the help.