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#1
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Sony ES op. amps/transistors: no nte cross reference / NLA ?
Hello Sirs,
I (hi-fi newbie)just bought a rough end sony es home amp from a pawn shop, m# tda-330es, that the protection circuitry comes on and stays on once the unit is powered up, I can only guess some homer didnt use proper pre-amplification/switching and/or cross phased the speaker output leads when he or she hooked this up last and cooked one of the final or main "stereo hybrid" op. amps, on diode/continuity test, this one transistor, p/n 2SA2921 (sanken), is wide open, and the body of the part looks like it got burned by an clutzy/overzealous "tech" with not enough time and too much soldering iron, it has a melted dimple in it, the solder leads for all four of these that go onto the final amp pcb look ratty also as the "tech" didnt clean up the rosin left in between the leads etc. Q: Are these transistors still available ? nte's cross ref. shows them both as obsolete and NLA, 2sa1215 and 2sa2921, HELP !!! Mouser shows some older jap p/n's like this in an older catalog from around 1999, I went to there 'site and did a search and nada. The unit is switchable between mono and stereo on the back panel, which works, indicating to me the unit still has logic/smooth 5vdc, on power up, the mono or stereo led lights up breifly but then goes back to the protection led, and stays on. Qv2.0: Are these sanken transistors origional equipment parts that came in the unit ?? if so, sony used way too much heat sink grease on these !! Also, should anything else be tested related to this besides the complimentary transistors etc ??? Any other suggestions or comments would be much appreciated, and forgive me if I have offended anyone in this group in any way by placement of this post .. Thanks in advance, Dave Carper .. |
#2
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Sounds like the burned one is bad all right, time to get it to a shop for
repair. Even if you manage to get some transistors to replace them with, the market has been flooded with substandard counterfeits. A knowledeable shop would be able to get high-quality replacements, hopefully. The 2SA1215 and 2SC2921 have been discontinued by the manufacturer, so any new ones with those numbers are fake. Mark Z. "Dave C" wrote in message om... Hello Sirs, I (hi-fi newbie)just bought a rough end sony es home amp from a pawn shop, m# tda-330es, that the protection circuitry comes on and stays on once the unit is powered up, I can only guess some homer didnt use proper pre-amplification/switching and/or cross phased the speaker output leads when he or she hooked this up last and cooked one of the final or main "stereo hybrid" op. amps, on diode/continuity test, this one transistor, p/n 2SA2921 (sanken), is wide open, and the body of the part looks like it got burned by an clutzy/overzealous "tech" with not enough time and too much soldering iron, it has a melted dimple in it, the solder leads for all four of these that go onto the final amp pcb look ratty also as the "tech" didnt clean up the rosin left in between the leads etc. Q: Are these transistors still available ? nte's cross ref. shows them both as obsolete and NLA, 2sa1215 and 2sa2921, HELP !!! Mouser shows some older jap p/n's like this in an older catalog from around 1999, I went to there 'site and did a search and nada. The unit is switchable between mono and stereo on the back panel, which works, indicating to me the unit still has logic/smooth 5vdc, on power up, the mono or stereo led lights up breifly but then goes back to the protection led, and stays on. Qv2.0: Are these sanken transistors origional equipment parts that came in the unit ?? if so, sony used way too much heat sink grease on these !! Also, should anything else be tested related to this besides the complimentary transistors etc ??? Any other suggestions or comments would be much appreciated, and forgive me if I have offended anyone in this group in any way by placement of this post .. Thanks in advance, Dave Carper .. |
#3
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You should have an experienced shop service the amplifier for you. If any of
the outputs are blown, you can be sure that there are other faults that must be serviced. Usually when there are blown outputs, the drivers, and other support components are also damaged. If this is the case, the new outputs will blow again as soon as the power is re-applied. The best transistors are the original ones, or ones that are a very close match to the original specs. It is also important that the transistors are pair matched to make sure that the cross-over distortion is kept at a minimum, and that the current balance is as accurate as possible. -- Jerry G. ===== "Dave C" wrote in message om... Hello Sirs, I (hi-fi newbie)just bought a rough end sony es home amp from a pawn shop, m# tda-330es, that the protection circuitry comes on and stays on once the unit is powered up, I can only guess some homer didnt use proper pre-amplification/switching and/or cross phased the speaker output leads when he or she hooked this up last and cooked one of the final or main "stereo hybrid" op. amps, on diode/continuity test, this one transistor, p/n 2SA2921 (sanken), is wide open, and the body of the part looks like it got burned by an clutzy/overzealous "tech" with not enough time and too much soldering iron, it has a melted dimple in it, the solder leads for all four of these that go onto the final amp pcb look ratty also as the "tech" didnt clean up the rosin left in between the leads etc. Q: Are these transistors still available ? nte's cross ref. shows them both as obsolete and NLA, 2sa1215 and 2sa2921, HELP !!! Mouser shows some older jap p/n's like this in an older catalog from around 1999, I went to there 'site and did a search and nada. The unit is switchable between mono and stereo on the back panel, which works, indicating to me the unit still has logic/smooth 5vdc, on power up, the mono or stereo led lights up breifly but then goes back to the protection led, and stays on. Qv2.0: Are these sanken transistors origional equipment parts that came in the unit ?? if so, sony used way too much heat sink grease on these !! Also, should anything else be tested related to this besides the complimentary transistors etc ??? Any other suggestions or comments would be much appreciated, and forgive me if I have offended anyone in this group in any way by placement of this post .. Thanks in advance, Dave Carper .. |
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