Incoming B-6...Might be a basket case...will need Avionics help for sure !!! FIXED, again !!!
they go out in spectacular fashion, indeed.Have a close look at C403 .22µf @125vac .. If it is a RIFA cap replace it with something along these lines..
https://www.mouser.com/ProductDetail/EPCOS-TDK/B32922P3224K000?qs=KUoIvG/9IlYIbH277z8slA==
Right!!! ugh, but I embrace this challenge .
Solder side repair ......another set of eyes to check is appreciated. Large 3k pic added, just click on it.
Athanasios
Ι was going to use epoxy but i misplaced my supply and just went with how I did it.
I know that the GND plane was ok but I figured id just do it for a peace of mind for myself.
I checked the large caps and they seem ok, Should I still go ahead and replace all 6? I saw your PM , thanks for that.
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Its up to you..
Maybe see if I can get it up and running before I go ahead with the most $$$ parts.
Athanasios
Especially in the 220v models.
Need to plot out the debris field.. With all those shorted outputs. There is definitely alot more collateral damage.
https://audiokarma.org/forums/index.php?threads/burned-yamaha-b-6.845549/page-2#post-12147751
https://audiokarma.org/forums/index.php?threads/burned-yamaha-b-6.845549/page-2#post-12147751
You got the concept. Is the execution that has room for improvementRight!!! ugh, but I embrace this challenge .
Solder side repair ......another set of eyes to check is appreciated. Large 3k pic added, just click on it.
Athanasios
I am not familiar with this model but I am not sure Yamaha mixed toshiba and fijitsu power / output transistors. My thinking is that someone already did some changes to the unit.Well 4 outputs are bad .......
Need to find replacements.
nashou
You should be able to find replacements from Sanken. Recently discontinued but B&D might still have some and they are not going to be cheap.
You got the concept. Is the execution that has room for improvement
Always looking for better methods. What do you suggest? Fly wires instead of solder? I guess it would prevent the stiff solder from cracking again if the board
gets flexed at the joint.
One thing I did not do and now wish I did was mark the locations of the bad TR's . But I did take a picture of the board before and am lucky that
2 bad outputs are not the sankens so I can locate that field .
I'll read that post and see what else usually goes.
All emitter resistors read fine so far as do the two smaller heat sinked 2SA673's .
All I checked so far.
Athanasios
yes
They have the originals as well for 3 more dollars a piece.
I guess I should keep them matched .
But......they don't have the 2SA1095 in stock. could I use the 2SA @avionic linked to with the original 2SC2565?
Or is it best to keep both he link to together and it won't make much a difference considering all the rest are the 2SC2565/2SA1095 combination?
50mhz vs 80mhz
@avionic might opine if the 30mhz would make a difference in this design (this amp was build during the "fast" amp wars; see Kenny L-07 and others), but I highly doubt it. @50mhz the Sanken are fast enough. While the Toshibas were excellent transistors and super fast, the Sankens are LAPT devices dual diffused with much better dissipation technology and more robust than the Toshibas. Don't take me wrong, if I had the choice I would use the originals too, but I would also not hesitate to use the Sanken if originals availability was iffy.
@avionic might opine if the 30mhz would make a difference in this design (this amp was build during the "fast" amp wars; see Kenny L-07 and others), but I highly doubt it. @50mhz the Sanken are fast enough. While the Toshibas were excellent transistors and super fast, the Sankens are LAPT devices dual diffused with much better dissipation technology and more robust than the Toshibas. Don't take me wrong, if I had the choice I would use the originals too, but I would also not hesitate to use the Sanken if originals availability was iffy.