My NAD T-748 home theater receiver died during a power fluctuation. It's dead and it's not the fuse. I think the problem may lie in the board which connects AC power from the line cord to the main transformer. The main power relay, on that board, has no coil voltage.
I've searched the net for a schematic and came up empty.
Does anyone have one?
thanks.
I've searched the net for a schematic and came up empty.
Does anyone have one?
thanks.
Check for 5.6volts on pin 3 of the regulator next to the standby transformer, IC414. I suspect the transformer T4001 has a blown thermal fuse.
some measurments
The Hi-fi Engine link is for the owner's manual. No schematic there.
I measured, in DCV: 0.47, 10.5 and 5.4 at the regulator.
The standby xmer has 117VAC on the primary and 9.3VAC on the secondary.
The relay has zero on the coil and 117VAC across the contacts. The coil reads 100 ohms.
Seems like I can jump the relay contacts and see if the receiver wakes up.
any further input is appreciated.
thank you all
The Hi-fi Engine link is for the owner's manual. No schematic there.
I measured, in DCV: 0.47, 10.5 and 5.4 at the regulator.
The standby xmer has 117VAC on the primary and 9.3VAC on the secondary.
The relay has zero on the coil and 117VAC across the contacts. The coil reads 100 ohms.
Seems like I can jump the relay contacts and see if the receiver wakes up.
any further input is appreciated.
thank you all
Manual/Schematic
Thanks for the reply. I couldn't get there. I got as far as the owner's manual. When I tried to get further, my anti-virus stopped me.
Thanks for the reply. I couldn't get there. I got as far as the owner's manual. When I tried to get further, my anti-virus stopped me.
You should have the link now. You don't install anything with Dropbox, just look for where it says to download the file.
excellent.Hi Guys. Could you please send me the link for the schematic as well? I received a Nad T748, briken, as a present and want to attempt to fix it, maybe by converting it to a plain old analogue amp... 😁
The link in post #2 takes you to the site hosting the manuals. You need to register but it is all free.