Yamaha RX-V863

[ga70gto]

Yamaha rx-v863 amplifier does not power on at all, no clicks. It also will not enter self diagnostic mode. There are several threads on the net for replacing a capacitor on the "sub power" (?) board but my board does not have that capacitor. there is also a thread detailing the replacement of a thermal fuse in the transformer but mine does not check "open". There is a small transformer on the board that provides 12 volts, it seems to power up and close a relay on that board which then provides line voltage (110v) to the main transformer. This relay does close and then 110v is available to the transformer when not plugged in but there is no amperage to do any work. I removed the sub power board from the unit, checked the voltage at the fuses and received apprx. 110v but as soon as you plug anything into the rear sockets of the board the voltage goes away thus my assuming there's no amperage to do any "work". I'd appreciate a shove in the right direction, the service manual is available for download on the net.

thanks in advance,
ga70gto

[budm]

Re: Yamaha RX-V863

When you said you have 120Vac at the fuse, how did you measure the Voltage? You measure Voltage the two ends of the fuse? You may also have bad relay contacts.

[ga70gto]

Re: Yamaha RX-V863

Hey Bud, thanks for responding. I checked voltage from chassis ground to the fuses, both fuses are good, I had voltage at both ends, lol. Problem is as per the pic once you plug anything in to the rear receptacles the voltage goes away or you might say goes to "0". It 'goes away when you plug in an incandescent desk lamp, if I plug in a phone charger the voltage ranges from about 50 to 90 volts and per the phone the charger turns off and on. My guess being turns on when the voltage reads 90v. It acts like a 12v DC car wiring system that's has lost it's ground.I had hoped for dirty contacts in the relay so I ordered one from Mouser, no go, same effect. Also, I was able to find a duplicate power supply on ebay and it has the same characteristics. it was my thinking that maybe this board is some how 'smart", if it doesn't see whatever it's looking for it won't work properly. I thought maybe this would be an easy fix since it doesn't do anything at all vs.some kind of intermittent problem. I've though about jumping power directly to the large power transformer but don't want to do that just yet. I was hoping to find some resistance values for the different power transformer leads but no luck yet.

as always thanks for your time,
ga70gto

[ga70gto]

Re: Yamaha RX-V863

one more thing, I had described this unit as an "amplifier", really it's a receiver/amplifier. Sorry if this caused any confusion.

[budm]

Re: Yamaha RX-V863

First of all when check the incoming AC to the unit, do not use the chassis GND as the GND ref for your meter, the correct way to measure the incoming AC is between LINE (HOT, or PHASE) and NEUTRAL, then between LINE after the fuse and Neutral, then LINE after the relay output contact and Neutral.
The relay on that standby board is just used for switching AC (LINE) to the main power transformer, and the switched OUTLET if it has one.
So there has to be measurement.

[budm]

Re: Yamaha RX-V863

BTW, the amperage is dictated by the resistance of the load being connected to that 120 VAC source, the higher the resistance the less current flow.
If you really have 120VAC through the relay contacts that goes to the HOT and Neutral pins of the connector that goes to the primary winding of the main power transformer when the power transformer is not connected, but then it drops down to 0 VAC when the transformer is connected, that means you have high resistance in the power line going to the power transformer.
You will have to check the ACV on the input side of the relay and the output side of the relay, and the traces and the connections all the way to the power transformer primary winding.
Service manual:
https://cdn.badcaps-static.com/pdfs/...4561d91119.pdf

[ga70gto]

Re: Yamaha RX-V863

By back probing the line connector I have apprx 125 volts in. Once the relay closes it supplies voltage through the two onboard fuses, one to the switched outlets, one to the main power transformer. I measured apprx. 120v at the fuses but plugging in an incandescent desk lamp to either of the switched outlets kills the voltage to 0. measuring the two leads of the primary side of the transformer I have line voltage, measuring across the secondary side I have 14.2v. the resistance of the primary side is 730 ohms, the secondary side 16 ohms.

I decided to do a bizarre test and desoldered the "contact" side of the relay. In fact the relay is not closing I had no continuity across it and I still had the strange voltage at the fuses when line voltage is applied to the board though but I don't think that's anything to worry about.

[budm]

Re: Yamaha RX-V863

There should be no strange Voltage with ref to Neutral and the input side of the fuse, or at the out put side the fuse, or at the input side of the relay contact, or at the output side of the relay contact. All those point should show 120VAC ref to neutral WITH THE TRANSFORMER CONNECTED.

measuring the two leads of the primary side of the transformer I have line voltage, measuring across the secondary side I have 14.2v. the resistance of the primary side is 730 ohms, the secondary side 16 ohms.
Is this the reading of the main power transformer?
Did you download the service manual?
What ACV do you have between the two relay contacts (you put the probes on each legs of the relay contacts) when the relay is on and the transformer connected?
Same for fuse.

[ga70gto]

Re: Yamaha RX-V863

Thanks again Bud. you can see I entered my post two hours after yours so it looks like to me the problem must be on this board and why aren't the relay contacts being closed?? One other thing, before I replaced anything on the board I plugged in the desk lamp to a switched outlet and sprayed each component with component cooler to see if voltage would be applied to the lamp, it made no difference.

[budm]

Re: Yamaha RX-V863

BTW, I need good straight shot pictures of the top and the bottom side of the board and the whole inside of the unit.

[budm]

Re: Yamaha RX-V863

Thanks again Bud. you can see I entered my post two hours after yours so it looks like to me the problem must be on this board and why aren't the relay contacts being closed?? One other thing, before I replaced anything on the board I plugged in the desk lamp to a switched outlet and sprayed each component with component cooler to see if voltage would be applied to the lamp, it made no difference.

But in post 1 you said the RELAY CLOSED its contacts.
it seems to power up and close a relay on that board which then provides line voltage (110v) to the main transformer

[ga70gto]

Re: Yamaha RX-V863

yes, I had my black meter lead back probing the line in connector and using the red probe to check for voltages and have those stray voltages at the fuses. because it's easier I'm working with the spare power source which is out of the reciever and on the bench, it is NOT connected to the main power transformer. those measurements I gave you were from the small transformer mounted on the board. I do have the manual downloaded.

[ga70gto]

Re: Yamaha RX-V863

Yes, it was my understanding that because I had this "stray" voltage the contacts were closed. I will post pics tomorrow and bring my fluke meter from work to recheck these measurements. I've worked on cars for 30 years so DC stuff i'm familiar with, AC i haven't done much other than house wiring.

Pete

[budm]

Re: Yamaha RX-V863

Black probe of the ACV meter should be at the AC INPUT CONNECTOR NEUTRAL WIRE (WHITE) you need to leave it on this NEUTRAL while you are tracing the LINE VOLTAGE, then use the read probe to trace the ACV all the way from the AC input connector Black wire and then all the way to the Black wire of the main power transformer.
It is the same as leaving your Black meter probe on the car chassis then you use the read probe to find out where the Voltage disappear, same concept, we are just dealing with jut Primary AC at this point.
Primary AC, WHITE wire is neutral, Black wire is HOT (LINE/PHASE).
Enclosed is the PDF of that small power supply board FUNCTION 3.

[ga70gto]

Re: Yamaha RX-V863

Bud, I became bored so here are a few pics to look over. let me know if you need different angles or other boards removed for clarity.

Pete

[budm]

Re: Yamaha RX-V863

OK, I look at the diagram for the FUNCTION-3 board, as you can see in the schematic, the is a relay contact snubber cap C2513 (0.01uf 250V) across the relay contact, so when the relay contact is not close you will see 120VAC at the transformer connector but the Xc of the cap is very high which will not allow much of the current to flow through the transformer winding or the load connected to the switched OUTLET, that is why you see the ACV drop to almost nothing when the transformer is connected or the lamp.
So basically the relay is not being turned by the processor I assumed if you did not hear the relay kicks in when power switch is activated.
Or the relay may be bad if you do hear it clicks, so did you hear the relay on that small click on or not?

[budm]

Re: Yamaha RX-V863

Hmm, your board is not using lots of parts as shown in the diagram. I need to study the service manual more in deep details to see what are actually being used on your board.
It does have C2513 so that section is correct.

[budm]

Re: Yamaha RX-V863

BTW, what is your exact model? RXV-863U?

[Clutchbox]

Re: Yamaha RX-V863

Are the mains-plug solderconnections okay?

[ga70gto]

Re: Yamaha RX-V863

I believe its a Rx-v863U as you had mentioned. the rear lists 120v and the front panel controls seem to match up with the front panel in the manual. The rear of the unit only lists RX-V863, no "U" or any other suffix.

There is NO audible click from the relay and as you noticed there are many components listed on the schematic that aren't present on the board.

So the question is why isn't the relay being commanded to close? As I mentioned before I did replace the relay on the original board because on vehicles I've heard relays click but that didn't necessarily mean voltage was transferred through the contacts.