Hello, I hope this message finds everybody well.
I recently embarked on two Pioneer Sa-7800 amplifiers: both in the HG version (i.e the 220V one, not the 120V one).
I noticed that the power assembly PCB is different for the two models, so I was wondering why?
The power assembly of the 1st amplifier is marked as "GWR-114" which is the ref. number in the schematics of several service manuals online.
The power assembly of the 2nd Amplifier, instead, is makes as "GWR-115", or GWR-1150. I can't trace back this number from anywhere.
The PCB looks similar to the previous, except for the fact there are only two fuses instead of three (the 3.15A is missing). The transformer also has a different part number, whereas the big caps are not from Nichicon.
This amplifier has a plug with only two pins thus it lacks of the GROUND connection to the chassis (the other has a 3 pins plug + chassis connection to GND). To be honest, I cannot understand how the chassis is earthed.
Yet, everything seems to be working and the chassis is not under voltage.
Apart from that, the two PCBs are very similar and both seem to work.
I guess maybe the 3.15A fuse may have been embedded in the transfo, and that there may have been some evolutions.
If possible, I'd appreciate if someone could confirm this is the case, or if the GWR-115 PCB comes from another Pioneer model.
Thanks for any help.
I recently embarked on two Pioneer Sa-7800 amplifiers: both in the HG version (i.e the 220V one, not the 120V one).
I noticed that the power assembly PCB is different for the two models, so I was wondering why?
The power assembly of the 1st amplifier is marked as "GWR-114" which is the ref. number in the schematics of several service manuals online.
The power assembly of the 2nd Amplifier, instead, is makes as "GWR-115", or GWR-1150. I can't trace back this number from anywhere.
The PCB looks similar to the previous, except for the fact there are only two fuses instead of three (the 3.15A is missing). The transformer also has a different part number, whereas the big caps are not from Nichicon.
This amplifier has a plug with only two pins thus it lacks of the GROUND connection to the chassis (the other has a 3 pins plug + chassis connection to GND). To be honest, I cannot understand how the chassis is earthed.
Yet, everything seems to be working and the chassis is not under voltage.
Apart from that, the two PCBs are very similar and both seem to work.
I guess maybe the 3.15A fuse may have been embedded in the transfo, and that there may have been some evolutions.
If possible, I'd appreciate if someone could confirm this is the case, or if the GWR-115 PCB comes from another Pioneer model.
Thanks for any help.
Hi, and thank you for your reply.
Indeed there are different versions. Online, I could find the service manuals for the KU and HG version only, whose power assembly boards are the GWR-112 and GWR-114, respectively. So it makes sense to suspect the GWR-115 belongs to another version. I could not find the manuals of the other versions, unfortunately.
Maybe one thing worth mentioning is that the GWR-112 has AC outlets, whereas my GWR-115 not. This may explain why the GWR-115 does not have a large 3.15A fuse.
Indeed there are different versions. Online, I could find the service manuals for the KU and HG version only, whose power assembly boards are the GWR-112 and GWR-114, respectively. So it makes sense to suspect the GWR-115 belongs to another version. I could not find the manuals of the other versions, unfortunately.
Maybe one thing worth mentioning is that the GWR-112 has AC outlets, whereas my GWR-115 not. This may explain why the GWR-115 does not have a large 3.15A fuse.