Chinese amplifier LSV PM 2568 overheats transistors.
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Greetings from Valledupar Colombia.
You say that the amplifier is almost complementary but the diagram you upload suggests that it is complementary by the signaling of the resistance at the output stage, although in fact the diagram is almost complementary.
Does that amplifier use four NT2625N transistors per channel?
If friend on the card is marked NT2625N which uses 2 pairs per channel, the diagram used as a reference, the resistance of 0.33 in this equipment is different. as a highlight, pay attention to any comments ..!
I am doubtful to replace the 2sc5200 because it differs in Ib = 1.5 amp in the 2sc5200 and in the NT2625N IB = 3 amp. but together I thought about that friend.
Regarding Ib = 1.5A in the 2sc5200 and in the NT2625N IB = 3A, what I can tell you is that this is a type of amplifier that does not require greater care, this one that I am repairing uses the transistor 2SD1047 and complementary.
I have put the 2SC5200 on several occasions and I have not had difficulties.
test with two transistors 2SC5200, if the stages of the drivers are fine it should not have that problem that you refer, I check that the isolation of the power transistors is fine ???
get me out of a doubt, what voltages are in the collectors of the power transistors in the two rows of transistors
TR1 voltage relative to ground
Vb = +0.3
Vc = +42
Ve = 0
TR2 voltage relative to ground
Vb = -42.2
Vc = 0
Ve = -43.4
ok brother as I was saying following his indication he had also chosen to replace these transistors with the 2sc5200, and for days I sent the owner to buy them, only he was afraid that the 2sc5200 would also heat, anyway in case they warm up a bit of the 0.33 ohm resistors taking them to 1 ohm, since it has been verified that what is heating it is the collector current, any news will be informing, we wait for the 2sc5200 to be achieved.
That transistor has become a universal component for many amplifiers and very commercialized worldwide.
You can upload more images showing the output transistors and the part where the drivers are, also the printed circuit which has to do with the amplifier stage.
My name Olger Quintero Tapia.
The 2SC5200 are a very good transistor for that amplifier, check all transistors and diodes that have to do with the amplifier stage 5551 _ 5401 _ 9014 especially those that are attached to the heatsink, that is not leaking or short.
I see in the images that there are burnt resistors which must be changed so they are measuring, I did not see the load resistors of the power transistors.
The load resistors are inside the friend aluminum duct and as I was saying it sounds like hair and the bias is excellent, they only heat the final transistors, the owner does not get the 2sc5200, since this country is blocked there are no foreign imports due to the sanctions Imposed you don't get something so simple, grateful for the support ..!
if there are two different ones that I have, I repair many of those and those two are my headaches, well I only have this one left, the other hand over
Another transistor that I recommend and that is very popular is the 2SC3858.
So to speak jokingly, that amplifier would laugh at life if it manages to get them and install them.
Close brother in Venezuela, the order also any questions we are here to help us ak my number +58 04248824639
greetings solve the problem by replacing these transistors with the 2sc5200 and increasing the emitter resistors to 0.5 ohm since the latter were still heating a little less than the previous ones, apparently the Chinese amplifier has some design problem.
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