• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

inherited a non-working Sony TA-N77ES

T

tonythemedia

New Member
Hi, my father-in-law recently passed away and he had an audio rack back in his closet full of high-end gear from the late 80's. One of the items is a Sony TA-N77ES Amplifier. He has the matching pre-amp, as well.
I attached it to a pair of Bose 901 speakers he had and have tried all day to get it working. I have attached an iPod with an RCA adapter to the variable input and set the volume very low. I have also tried the fixed input.
  • The unit powers on with the protection light on, then after 7 seconds the protection light turns off and I can hear at least one relay clicking.
  • The stereo or mono light is working based on what I have the switch to set in the back.
  • The meters are lit and both are moving.
  • If I turn the attenuator knobs, the meters change accordingly.
  • If I move the fixed/variable switch, I do hear a relay switching and the meters indicate no signal until I physically move the rca from one input to the other.
  • I tested for continuity between the speaker outputs and the posts on the vertically mounted board and everything checked out.
  • The heatsink on the right gets warm after a few minutes so I think the transistors are working.
  • None of the capacitors that I can see look damaged, but I did not remove the black plastic housing labeled "audio capacitor".
I downloaded the service manual, but I'm not sure where I should start given the above information. Does anybody have any advice or guidance for me, please?
Thank You
Tony
 
Register to hide this ad
Tony, maybe a pic of the front to show how the selectors are set and pic of the rear showing how you have it hooked up. Seems like the amp is working from your description.

I'd probably:
iPod connected to 'fixed' input, switch in front to 'fixed'.
speaker selector to 'A' and connected to 'A' binding posts.
turn up the attenuator knobs to max

might seem simple but sometimes something gets overlooked. Looks like a nice power amp.
 
rickl said:
Tony, maybe a pic of the front to show how the selectors are set and pic of the rear showing how you have it hooked up. Seems like the amp is working from your description.

I'd probably:
iPod connected to 'fixed' input, switch in front to 'fixed'.
speaker selector to 'A' and connected to 'A' binding posts.
turn up the attenuator knobs to max

might seem simple but sometimes something gets overlooked. Looks like a nice power amp.
Click to expand...

I did all of that. The attenuator knob only affects the variable input, not fixed, per the manual.
 
Needs systematic diagnosis to find the fault(s).
I replaced a defective driver module in one, iirc, I think those can be somewhat suspect.
 
Crank your two input attenuators fully CW... Reduce the volume on the ipod.
 
avionic said:
Never ! Never! Never ! Mess with the speaker connections with power applied to the amplifier. Your flirting with disaster..
Click to expand...
The amplifier is and easy fix if ... you don't blow up and output device by shorting out the output with speaker wires flopping around.
 
avionic said:
No.. It is not.. Listen ..your the one asking for help.

Send it to a tech. If you don't feel that a little cooperation on your end is worth free technical consultation on my end.

You sir have just burnt a bridge with me..

Helluva way to start at Audio Karma..
Click to expand...
The positive terminal on the amp goes to the positive terminal on the speaker.
The negative terminal on the amp goes to the negative terminal on the speaker.

I have two other amps here, if I move the wire to the other amps, it works. The wires going to the speaker are solid. There is something wrong on the inside of the amp, which is what I'm trying to troubleshoot. It is connected correctly.
 
Down load the owners manual...Make sure you know what the switches are suppose to do. Possibly and operator error.

https://www.hifiengine.com/manual_library/sony/ta-n77es.shtml

1. Protect relay " clicks " --- good sign
2. Meters show signal presents. --- good sign

You have and issue with signal routing from the meter circuit to the speaker binding posts -- switching issue perhaps.Relay issue perhaps.
Do you hear a relay " click " when selecting Speaker A or Speaker B ?

Switching problems are a lot easier to trouble shoot than amplifier assemblies.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom