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Bleed between inputs?

G

gonebytim

Active Member
Hi guy's

I'm trying to fix a Pioneer Rondo 2000 (no schematic or service manual available online).

There is significant bleed from the Tape input onto all the other inputs (ie - if I have an audio source connected to the tape input and then move the input select switch to phono or the tuner inputs - I can hear the tape input source through the other inputs). It's not as loud as when I have the tape input is selected - but it's still a significant volume).

Does anyone have any thoughts on what type of component could be bad to be allowing the tape input to bleed through? Just to give me a place to start looking....
 
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Poor grounding, routing of the cables (too close to each other along with poor grouding). Check the grounding of the shielded cables from the Tape input at both ends. It may be one end is grounded or both. In either case DO NOT CHANGE. Just fix the bad ground. also check for bad grounding at the board connection, and the chassis connection (I'd clean and retirghten all of them to start with).

If you have a spare input, transfer the source on the tape input to the spare and see if the bleed over still occurs. If not, this strengthens the poor grounding option.

You could always just turn off the source on the tape input and listen to the other's.
 
larryderouin said:
Poor grounding, routing of the cables (too close to each other along with poor grouding). Check the grounding of the shielded cables from the Tape input at both ends. It may be one end is grounded or both. In either case DO NOT CHANGE. Just fix the bad ground. also check for bad grounding at the board connection, and the chassis connection (I'd clean and retirghten all of them to start with).

If you have a spare input, transfer the source on the tape input to the spare and see if the bleed over still occurs. If not, this strengthens the poor grounding option.

You could always just turn off the source on the tape input and listen to the other's.
Click to expand...
Actually - the small ceramic capacitor which is soldered between the ground of the tape input RCAs and the chassis looks a bit suss - like it might be breaking apart from age, I'll replace it and see if that helps, other than that - all the grounds seem to be solid, I've resoldered every one of them to make sure . The theory seems to be make sense though because the ground should be the only point in which the various sources could mix - is that correct?
 
might be bleeding through dirt switches .. on some old equipment it did this from new .. what sort of age is it ?
 
petehall347 said:
might be bleeding through dirt switches .. on some old equipment it did this from new .. what sort of age is it ?
Click to expand...

I was thinking about that too. It's late 70's

Interesting thing about this design is that the phono inputs are wired directly to the switch before going through the phono preamp circuit. I'm guessing that the switch actually cuts the phono input off completely when other inputs are in use and that the phono signal actually passes through the switch twice (once before and once after the phono preamp circuit). Which just seems like an extra point to fail. The other receivers I have are simpler with the phono input just passing through the phono stage before reaching the switch
 
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