I have an NAD 7140 receiver. When trying to clean the pots and switches, they are obscured by boards above and below. The bottom appears to have about 10 connections screwed to a cross bar. It looks there is some type of white sealant or insulation underneath each connection. May I safely unscrew those to allow the board to shift enough to reach the pots?
Looking at this picture
NAD 7140 Photo #1722728 - US Audio Mart
The transistors are fixed to the laminated heatsink at the right of the transformer.
You can actually see the legs. Seem to be soldered to the bottom board or socketed, so perhaps You can lift the upper board. Try removing the front perhaps there is access.
NAD 7140 Photo #1722728 - US Audio Mart
The transistors are fixed to the laminated heatsink at the right of the transformer.
You can actually see the legs. Seem to be soldered to the bottom board or socketed, so perhaps You can lift the upper board. Try removing the front perhaps there is access.
That picture is a view from the top. I have removed the face panel, but no access. The board I'm curious about is seen from a bottom view and is a rather large board. Based on what little I could glean from an NAD 7140 service manual...the board to which I'm referring is the amplifier board. Towards the back of the receiver, there are 6-8 connections screwed into a crossbar. Each connection has three little legs that attach to the board. The front of the board, (forward facing to the faceplate) appears to fit into "clips" (for lack of a better word). It appears to me that all the connections to the crossbar should be unscrewed, then the entire board may be able to slide back a couple of inches.
I don't know a lot about electronics...possibly just enough to get into trouble and be dangerous.
I don't know a lot about electronics...possibly just enough to get into trouble and be dangerous.
Figured out that what I'm looking at are transistors, and they are more than likely on the amplifier board, if that helps.
The board You mention is perhaps the brown one on the picture, so the lower board.
I believe if You lift the green board (Tuner & logic) You will have access to the pots / supply /amplifier.
I see only 6 screws on top & perhaps you need to remove the display board also.
I believe if You lift the green board (Tuner & logic) You will have access to the pots / supply /amplifier.
I see only 6 screws on top & perhaps you need to remove the display board also.
Tried to remove the top board. You're correct, just six screws. Edges were all loose and could be lifted a bit...but something near the center of the board was holding it very firmly. I stopped right there because I didn't know what I was doing. Didn't see anything that looked like it was holding the board in position. Removing the face plate didn't help, nor did removing the bottom plate. Buttoned her back up. Sprayed tuner cleaner and lube on the combination volume/balance control shaft and let gravity do its thing. Did that several times, apparently just enough eventually worked in there to clean up the volume completely and improve but not fix the balance...still scratchy.
Time to resort to a pro.
Time to resort to a pro.
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