Yamaha A-1020 Help Please!

Hello,

This is my first time posting here. I just received a Yamaha A-1020 amp. The person that gave it to me said that it started acting funny one day would have an output the next not. When I hooked up the amp it worked fine and truto what he said the next day when turned on no output. Has anyone had this problem? Thank you for your time and help on this post.

Thank you.
Perle

Hi Perle,

Maybe this manual will help you.

View attachment YAMAHA A-1020.pdf

Best wishes,
ca2102

Good day ca2102,

Thank you for the reply. I will save and print this out. The amp does have an output but is is very low. You need to have your ear next to the speakers to here the output.

Thank you again,
Perle

For an intermittent like that I'd be suspicious of the contacts in RY201 (relay). Try tapping on the relay while the unit's turned on at a low volume level.

Good day KJ6EAD,

I will try this, thank you. I will post the results.

Thank you again,
Perle

Good day ca2102,

I just want to thank you for the reply and service manual. I have the amp working now. After reviewing the pc board I found cold solder joints. The main ones that were visible under the mag light were the 3 watt power resistors R345-R352 (1.8k ohm and 2.2k ohm). Since I found these to be visible I just resoldered the rest of the joints to be safe. I checked all the voltage points and they are close. For example the B+ and B- per the spec should be 57.4v I am at about 63 volts. All of the functions, inputs and outputs are working fine. The only question I have is on the mute. When mute is selected it lowers the volume down quite low but does not totally mute the output. I don't know if this is normal for this amp.
Thank you again for your help.
Perle

---------- Post added at 10:26 ---------- Previous post was at 10:25 ----------

Good day KJ6EAD,

I also want to thank you for the reply and help. I have the amp working now. After reviewing the pc board I found cold solder joints. The main ones that were visible under the mag light were the 3 watt power resistors R345-R352 (1.8k ohm and 2.2k ohm). Since I found these to be visible I just resoldered the rest of the joints to be safe. I checked all the voltage points and they are close. For example the B+ and B- per the spec should be 57.4v I am at about 63 volts. All of the functions, inputs and outputs are working fine. The only question I have is on the mute. When mute is selected it lowers the volume down quite low but does not totally mute the output. I don't know if this is normal for this amp.
Thank you again for your help.
Perle

It's amazing and amusing how many faults can be found by careful visual inspection or poking with a stick.:roll: