Posted previosly in Vintage solid state.
I just finished recapping my two SX-1280's with MARK's help and I'd like to give it one more shot. I had a technician (that specialize in vintage audio!!!!)to look at it, but he could not fix it. So, here are the symptoms:
When powering the unit ON, with or without any input, tone amp switch ON or OFF, filters ON or OFF, volume control HI or LO there is NO pop. Immediately after powering, turning the tone switch ON or OFF, it results in loud pop in both speakers. At the same time, with the tone amp switch OFF, turning the LOW filter ON or OFF will also result in pop, but not as loud. The pop is louder when turning both switches OFF!!! After about one minute of a warm up time, OR flicking the tone switch ON/OFF, there is NO pop!!! Turning the unit OFF, with or without any input, with volume all the way down, there is NO pop. However, with the volume up, there is a pop in both speakers. So far I changed the position of caps C29 and C30 on tone amp AWG-039, cause on the board they show different hook up then in the schematics (pin #1 and #3 goes to plus in the schem. and to minus on the board). The schematics of SX-850 also shows pins #1 and #3 connected to plus side. So I did what the schematics shows. Not much inprovement. Unless the schematics are wrong, all the caps are hooked up accordingly, using Nichicon UKL's in all sensitive places.
There it is, any ideas?
Thanks
I just finished recapping my two SX-1280's with MARK's help and I'd like to give it one more shot. I had a technician (that specialize in vintage audio!!!!)to look at it, but he could not fix it. So, here are the symptoms:
When powering the unit ON, with or without any input, tone amp switch ON or OFF, filters ON or OFF, volume control HI or LO there is NO pop. Immediately after powering, turning the tone switch ON or OFF, it results in loud pop in both speakers. At the same time, with the tone amp switch OFF, turning the LOW filter ON or OFF will also result in pop, but not as loud. The pop is louder when turning both switches OFF!!! After about one minute of a warm up time, OR flicking the tone switch ON/OFF, there is NO pop!!! Turning the unit OFF, with or without any input, with volume all the way down, there is NO pop. However, with the volume up, there is a pop in both speakers. So far I changed the position of caps C29 and C30 on tone amp AWG-039, cause on the board they show different hook up then in the schematics (pin #1 and #3 goes to plus in the schem. and to minus on the board). The schematics of SX-850 also shows pins #1 and #3 connected to plus side. So I did what the schematics shows. Not much inprovement. Unless the schematics are wrong, all the caps are hooked up accordingly, using Nichicon UKL's in all sensitive places.
There it is, any ideas?
Thanks
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