Fisher 800C Restoration Thread

[dcgillespie]

No. 1: Yes.

No. 2: Usually bad coupling caps. Make sure you’re using the correct phono inputs. I forget whether the Phono Low and High labels refers to the sensitivity of the inputs, or the output of the cartridge being used, so try both to make sure you’re using the correct ones.

Dave

 

[mcaddie7]

No. 1: Yes.

No. 2: Usually bad coupling caps. Make sure you’re using the correct phono inputs. I forget whether the Phono Low and High labels refers to the sensitivity of the inputs, or the output of the cartridge being used, so try both to make sure you’re using the correct ones.

Dave

All caps / film caps have now been replaced in this unit, I wouldn't "think" it's that but you never know. I'll try a different table tonight and the hi phono input and see. I know people say the phono input on these isn't great but what I heard was a pretty loud buzz. The crackle / hiss every 30 seconds or so was also concerning via the phono input...

Will update this evening!

 

[Mr Boochie]

All caps / film caps have now been replaced in this unit, I wouldn't "think" it's that but you never know. I'll try a different table tonight and the hi phono input and see. I know people say the phono input on these isn't great but what I heard was a pretty loud buzz. The crackle / hiss every 30 seconds or so was also concerning via the phono input...

Will update this evening!

I'm sure you've already done this, but for completeness, have you used a good contact cleaner on all tube pins, sockets, connections, etc.?

Thanks!

 

[mcaddie7]

I'm sure you've already done this, but for completeness, have you used a good contact cleaner on all tube pins, sockets, connections, etc.?

Thanks!

I have! I did this with the tubes removed when they were first tested. I believe there are only 2 tubes associated directly with the pre amp correct? I'll clean those again. I think I can exonerate the tone tubes / circuitry, as well as the amp circuitry given how pleasant the main amp sounds via Aux input. I think I can rule out the AM/FM section as well given it's currently unplugged due to that AM IF that needs fixing.

 

[Mr Boochie]

Have you tried replacing the tubes in the phono stage? I'm just trying to rule out the usual suspects.

 

[mcaddie7]

Have you tried replacing the tubes in the phono stage? I'm just trying to rule out the usual suspects.

Not yet! Was going to maybe swap with some other's on the recevier. Which tubes do you think could be the problem? Just the two pre amp ones or others?

 

[Mr Boochie]

Not yet! Was going to maybe swap with some other's on the recevier. Which tubes do you think could be the problem? Just the two pre amp ones or others?

Try rotating one pair at a time. Just a note: the sections with the highest gain (phono stage and input of pre-amp), have the highest chance of introducing noise to an amp.

 

[notdigital]

Rotating the tubes is a good idea. But before doing so, rock the tube in place once the "noise" begins. That way you can isolate the tube and/or a faulty socket.