I had the very same issues with my TFM-25, including more toasted areas on the board than are shown in the Service Bulletin. The parts were cheap so, rather than just hoping nothing would fail, I replaced every part over every toasted area on the board and elevated the replacement parts 3/8" above the board to better dissipate heat. Mauser and Digikey didn't stock those 1/4 watt flame proof resistors called out in the Service Bulletin so I substituted 1/2 watt standard resistors for those. While I was at it, I replaced all of the electrolytic caps. The link at the end of this post is a write-up I did on another web site covering the recap and Service Bulletin repair. I bet your idle current alignment is way off on that weak channel (mine was).
The parts lists in my linked writeup show only the caps and Service Bulletin replacement parts, not the other toasted parts that I replaced. So, below the link is the actual parts list I used, which includes all of the resistors and transistors I replaced (probably the same parts that could be compromised in your amp too).
All parts purchased online from Digikey except for the transistors, which were purchased from online B & D Electronics. The total parts cost was about $67 including all new caps.
Anyway, this was my very first electronics repair and it turned out OK in the end. The amp now has stable rail and bias voltages and it sounds wonderful. The new caps really improve the dynamics too. Hope this helps and good luck with your amp.
Link to writeup with photos: http://thecarversite.com/yetanotherforu ... sts&t=1683
Toasted parts replaced:
Item Carver PN Qty B & D PART# Description
Q201, 2SA1370-E,F 4 2SA1370
Q203, 2SC3467-E,F 4 2SC3467
Q451 2SD2012 1 2SD2012
Q452 2SC1815-Y,GR 1 2SC1815
R201 KA25ST911J 3 910Ω, 1/4W, 5%, carbon
R205 KA25ST102J 4 1kΩ, 1/4W, 5%, carbon
R209, REPLACE WITH 62W, 1/4W, carbon, FP
R218 KA25ST122J 2.2kW, 1/4W, 5%, carbon
R229, REPLACE WITH 1.5kW, 1/4W, carbon
R243, REPLACE WITH 22W, 1/4W, carbon, FP
R245, REPLACE WITH 27W, 1/4W, carbon, FP
R281, KA25ST222J 2.2kW, 1/4W, 5%, carbon
R283, KA25ST562J 5.6kW, 1/4W, 5%, carbon
R451 KA16ST471J 470W, 1/6W, 5%, carbon
R452 KA16ST102J 1kW, 1/6W, 5%, carbon
Must verify R235-238 are 1/2W (some amps came with ¼ W)