Hello
I’m looking at an old Blues DeVille that has low somewhat distorted volume.
I’ve already tried replacing the old tubes one by one (no change) and have run a hot soldering iron over the solder joints for the power resistors R85 and R86. I know that these often melt the solder at their connections but that doesn’t seem to be the case here. The plus and minus 16 measures good at these resistors.
I also had to resolder the input jacks.
I’ve been looking at and measuring the DC voltages on the circuit board with reference to the schematic.
All look normal save for the positive lead ends of capacitors C42 (schem says it should be 364vdc but it reads 234) and C35 (schem says 413 and it measures 231).
Anyone have a thought on this one?
Additionally I’d like to ask about a problem I’m having when trying to measure AC voltages on the board. When I try to measure the voltages they immediately go down, especially the millivolt measurements. I’m using a Fluke DMM meter, actually two different ones, and both exhibit the same problems. What am I doing wrong or missing?
Thanks in advance - schematic listed below
earache
https://www.thetubestore.com/lib/the...-Schematic.pdf
I’m looking at an old Blues DeVille that has low somewhat distorted volume.
I’ve already tried replacing the old tubes one by one (no change) and have run a hot soldering iron over the solder joints for the power resistors R85 and R86. I know that these often melt the solder at their connections but that doesn’t seem to be the case here. The plus and minus 16 measures good at these resistors.
I also had to resolder the input jacks.
I’ve been looking at and measuring the DC voltages on the circuit board with reference to the schematic.
All look normal save for the positive lead ends of capacitors C42 (schem says it should be 364vdc but it reads 234) and C35 (schem says 413 and it measures 231).
Anyone have a thought on this one?
Additionally I’d like to ask about a problem I’m having when trying to measure AC voltages on the board. When I try to measure the voltages they immediately go down, especially the millivolt measurements. I’m using a Fluke DMM meter, actually two different ones, and both exhibit the same problems. What am I doing wrong or missing?
Thanks in advance - schematic listed below
earache
https://www.thetubestore.com/lib/the...-Schematic.pdf
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