Fisher 400 volume inconsistancy?

I have a fisher 400 recevier that seems to work perfectly, with one exception. I was wondering if this is normal for these receivers or if it is really somthing that needs to be fixed.

When I turn up the volume from all the way down up to 1/3rd the volume increases normally. When I continue turning it up from 1/3rd to 1/2 way (noon) there is little if any audible increase in volume. After 1/2 it does start increase again, but I do not go much past that as it seems to strain very slightly. This occurs with different speakers that I have tried in the bookshelf size range.

Has anyone else experienced this? Is it a problem? Is ther a fix that would improve the performance? Thanks in advance for any suggestions.

Dmac

Methinks it's time for a deoxit blast!

Open it up, carefully stick a tissue under the volume pot to soak up the excess fluid, and blast away making sure to exercise the pot its full range. You'd be surprised at how much havoc oxidation causes.

Definately clean the pots with DeOxit D-5. Ratshack stuff won't cut the oxidation. Neither will The CRC stuff. Get your straw up inside the pot and give it a good shot, then turn it a couple times to spread it around. Let it sit for a 1/2 hour to soak in. Then give it a lite spritz and work the BEEJEZUS out of it. That should clean off the oxidation and corrosion and leave you with clean crabon tracks. My 800-C does the same thing on a smaller scale. But it's worn out and needs a new pot. Mark OPPAT can rebuild them. www.oldradioparts.net

Thanks

I found detox it at Guitar Center. It worked well. Thanks for the suggestion, but Just before I went to GC the receiver started producing distortion out of both speakers. I tried several inputs and fm, all are distorted. This seems to be an unrelated problem to the previous issue. Back to the drawing board.

Swap the Phono tubes (under the shields) with the tone amp tubes (up front). If not them, then try the phono tubes in the phase inverter / driver positions.

Check power voltages from the filter caps (B+), and bias voltages off the dual cap.

Larry

Thanks

Thanks Larry,

I think that I had a wire crossed somewhere. After moving things around and fooling with the speakers, the problem seems to have gone away.Not sure what it was,but glad it is gone