Jailtime
Standin' on a corner
Been making some nice progress last few days, rebuilt all the tone, preamp, and filter boards. It took some creativity to fit WIMA film caps on the PD01 tone board, don't think I'd recommend trying that. Managed to break a few solder pads on the PD01 board, thanks to Marantz's piss poor design that puts all the stress on those little pads. I replaced all the transistors on PD01 as well, I really don't want to separate it again. KSC1845 and KSA992 will cover those.
There's 4 of those little VD1212 varistors on the PE00 preamp board, they're marked as RE21, 22, 23, and 24 on the board. That's clearly not right, another error on a Marantz circuit board.
Also installed some nice Mallory filters, they're 4.125" tall and just fit. Nice to have that bit of extra space, gives you some more options for filters. I put 3.3uF bypass caps on the filters. While I was working on the filters, one of the socket tabs for those goofy diodes (?) mounted on the heatsink just crumbled. I hard wired directly to the diode leg to fix that. Something to be aware of when you're digging in there, those things are delicate.
I got my scope tube reinstalled as well, seems I only have a vertical line from center when "audio" button is engaged. I'm guessing those FETs on the driver board are the culprit. I'm just happy that the scope has a trace at all right now.
I have a weak rear right channel in 4x50 mode also, it was that way on my baseline test, was hoping it would just fix itself during the resto. It's basically whisper quiet. I suppose the problem could still lie in the amp boards that I haven't rebuilt yet.
There's 4 of those little VD1212 varistors on the PE00 preamp board, they're marked as RE21, 22, 23, and 24 on the board. That's clearly not right, another error on a Marantz circuit board.
Also installed some nice Mallory filters, they're 4.125" tall and just fit. Nice to have that bit of extra space, gives you some more options for filters. I put 3.3uF bypass caps on the filters. While I was working on the filters, one of the socket tabs for those goofy diodes (?) mounted on the heatsink just crumbled. I hard wired directly to the diode leg to fix that. Something to be aware of when you're digging in there, those things are delicate.
I got my scope tube reinstalled as well, seems I only have a vertical line from center when "audio" button is engaged. I'm guessing those FETs on the driver board are the culprit. I'm just happy that the scope has a trace at all right now.
I have a weak rear right channel in 4x50 mode also, it was that way on my baseline test, was hoping it would just fix itself during the resto. It's basically whisper quiet. I suppose the problem could still lie in the amp boards that I haven't rebuilt yet.