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Hello everyone,
Been trying to troubleshoot my Yamaha Ca 810 amp.No relay click upon
powering up the unit.No blown fuses.Opened her up and took some voltage
readings.Have the service manual, and tested TR 606.Getting the 41 vdc.
I am stuck at where else I can trouble shoot to find out why the relay
wont engage so i can get sound.
Follow Ups:
Thanks for the reply.I checked the dc idling voltage when I first
opened it up.It was only off by a small amount of voltage.After I did
the adjusting of the idling voltage,same issue.I will check the dc offset
voltage here real soon along with removing the output transistors.
Dennis
First:
One thing to check is to trace where the speaker outputs tie from the amp boards / circuit to the relay circuit. The relay will not engage if you have DC on the speaker outputs. If the DC offset is off enough, the relay will not engage. The service manual will tell you where to set this.
Second:
Another thing to try is to remove the output transistors and power the amp up. I've done this in the past to determine if I indeed had blown output transistors. Just make sure to note on the location of each transistor. You don't want to reinstall them in reverse, NPN into a PNP and vise versa. Also, don't mix the pairs up for each channel. Output transistors are matched.
If your relay clicks in with the output transistors removed, then best bet is you have a shorted transistor. I've seen the fuse not blow when an output transistor shorted. They tend to take out resistors down stream in the circuit or blow traces off the circuit boards.
Hopefully this will help. :-)
Not sure if u got my first reply.I have a Yamaha ca 510.The output transistors were blown.When u turned on power, a fuse would blow.
I replaced both of them..problem fixed.This one is a little different
being that no fuses blow when turning on the unit.The relay wont engage
at all.I will try removing the output transistors you spoke of keeping
in mind what u said about not getting them mixed up.
Dennis
You are going to have to use the schematic and trace voltages coming IN, across the relay board and the relay itself.
Also one problem that line had was fault tracings. I had a number of them that the tracing in the PCB just lifted off. Check all the connections were the any in/out going wire is attached for lifting.
charles
Hi Charles,
Thanks for the reply.Bro..this schematic I have is going to drive
me crazy.I can barely see the values,plus on this board, I dont see
any markings for the electronic parts.Like the corresponding part number.
Dennis
I had a CA 610 a number of years ago that I acquired as a non-working garage sale item. In that case, I found that a small electrolytic cap associated with the relay circuit had dried up which resulted in the relay not closing. Replacing the cap fixed the problem in that case.
You might want to look to see if this is the case with your 810.
Mike
Mike,
Here is a picture of the main board.If u look at the white resistor,
just to the left between the relay and the resistor, that diode didnt
when i checked it didnt give me any voltage readings at all.
That diode is across the relay coil. No voltage on the cathode side would be correct if the unit is in "protect". You will only have voltage there when the relay is energized in the working state.
Here's a copy of the schematic. It is probably due for a recap and a bad electrolytic may be the cause of your trouble, as was already mentioned.
I'll email you a copy of the schematic.
I'm afraid that I can't be much help beyond the specific situation that I mentioned in my previous post. I tend to be more lucky than knowledgeable when I work on vintage equipment.
You might go over to the AudioKarma site and do a search on posts by Merrylander. He was the person that helped me when I resurrected the 610. He was that site's resident Yamaha guru, although he is retired now. They also have a Yamaha specific forum, so someone else might be able to provide more detailed help.
Good luck,
Mike
Hi Mike,
Thanks for the reply.So far I have done some voltage checking around the
relay area, and have found so far that a diode has no voltage on it at
all.This schematic I have i dont like.The main circuit board doesnt have
any identification on the board for the parts.It just has the part on the
board, and thats it.
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