Hi!
few years ago my son unfortunately overloaded Technics SU-A900MK2 amp, full volume on 2x 100W 4ohm speakers... This exact device was in 2 service shops and both told that it has faulty AMP and it's not worth it repairing so they put their hands away from it.
AMP "does not amplify", it just leaves the sound that comes into the AMP
I haven't seen any burnt transistor, shorted capacitor or burnt route on the PCBs, relays do turn on so the protection is fine
the 2 power modules - SVI3205B + RSN6000B seems also fine, zener diodes checked with multimeter, nothing weird 🙁
RSN6000B does have a power transistors which can be purchased from link below - 2SJ338 + 2SK2162
https://www.ebay.com/itm/192202054620
17.2V rail does provide 17V
Q751 + Q752 are quite hot -- they wobble so the solder is melting
I will try reflowing the PCBs, desoldering the transistors and checking them.. in best scenario I wish hopefully the transistors inside the RSN6000B are faulty and nothing else 😀
Does anyone had a similar issue with Technics AMP ?
Schematics included in the attachment
Thanks a lot for your thoughts!
few years ago my son unfortunately overloaded Technics SU-A900MK2 amp, full volume on 2x 100W 4ohm speakers... This exact device was in 2 service shops and both told that it has faulty AMP and it's not worth it repairing so they put their hands away from it.
AMP "does not amplify", it just leaves the sound that comes into the AMP
I haven't seen any burnt transistor, shorted capacitor or burnt route on the PCBs, relays do turn on so the protection is fine
the 2 power modules - SVI3205B + RSN6000B seems also fine, zener diodes checked with multimeter, nothing weird 🙁
RSN6000B does have a power transistors which can be purchased from link below - 2SJ338 + 2SK2162
https://www.ebay.com/itm/192202054620
17.2V rail does provide 17V
Q751 + Q752 are quite hot -- they wobble so the solder is melting
I will try reflowing the PCBs, desoldering the transistors and checking them.. in best scenario I wish hopefully the transistors inside the RSN6000B are faulty and nothing else 😀
Does anyone had a similar issue with Technics AMP ?
Schematics included in the attachment
Thanks a lot for your thoughts!
Attachments
Last edited:
Hello
I also would like to buy such a 900mk2 amplifier, but I put some questions. Does it sounds good?
My other question is regarding the fan on the back. Is it switch on/off many times? I was thinking maybe there is a possibility to completely disconnect it somehow? Honestly I never ever had any amplifier with fan with it. I don't know why Technics installed that fan that ig can be annoying some time. How warm generally the amplifier? Thank you.
I also would like to buy such a 900mk2 amplifier, but I put some questions. Does it sounds good?
My other question is regarding the fan on the back. Is it switch on/off many times? I was thinking maybe there is a possibility to completely disconnect it somehow? Honestly I never ever had any amplifier with fan with it. I don't know why Technics installed that fan that ig can be annoying some time. How warm generally the amplifier? Thank you.