Onkyo HT-R510 turns on and then immediatly off

[redbaron1007]

I picked up an Onkyo HT-R510 that when I plug it in and press the power button will turn on and then a couple of seconds later turn itself off. When it turns on you can hear the relay click and then immediately click again and shut the power to the system off. I spent about 5 hours today trying to troubleshoot it and I did make some progress that may not actually tell me anything. It's still not really working and I'm not quite sure where to go next.

Here's everything I've done so far.

The first thing I did was open it up and check for any burn marks exploded parts or blown caps, but I didn't find anything visibly/obviously wrong with anything in the system. I tried disconnecting the board with the speaker jacks and the source input boards just in case something in them was shorting causing the amp protection system to kick in. It did the same thing when they were disconnected. I left the inputs and outputs disconnected and decided to press the power button about 5 times to see if I could get enough power into the amp to see if any of the components were getting warm. I found one NPN transistor (d2061 NPN) that was getting hot to the touch. I checked it in circuit with my dmm and nothing seemed off about what I was reading so I desoldered it and stuck it into my component tester. It read as a working NPN. Since this is a multi channel receiver I tried turning it on with the d2061 removed to see if it would stay on and it was still shutting off immediately. I did the power cycling again and found that the transistors on a vertical daughter board of the amp circuit was getting hot on the portion that corresponded to the channel that had the heating up transistor in it (photo 2). My next idea was to leave the d2061 out and also pull that daughter board out and see if it would turn on without it installed and it finally stayed on for an extended period of time. I never left it on for more than about 5 minutes just incase it somehow was putting stress on some other components. I checked around and nothing was getting hot on the main amp circuit so I figured whatever was wrong with the amp circuit was on the daughter board. I put it back in, turned it on and off a few more times to warm up the transistors on the daughterboard and found a PNP transistor (A1024 PNP) that was getting hot. I pulled the daughter board again and desoldered the PNP to test it. It was testing as a working pnp as well. I reinstalled the d2061 into the main board and left the A1024 out of the daughter board and put everything back together enough to test it. It was still clicking on and off. I did the power cycling for heat thing again and the d2061 that was getting hot before was now fine and cool to the touch but a couple other of those and a couple other of the A1024's on the daughter board were starting to get hot. At this point I was getting a little frustrated with it and decided to just remove all the d2061 and A1024's from the amp circuit and test them and they all read as working with no faults.

After a few hours of doing all this I started looking at the logic boards chips and using the power cycling to try to see if anything was getting warm, but I couldn't find anything that was heating up. I checked some voltages and checked for shorts with my dmm and I couldn't find anything out of the ordinary on the logic side of things. Reluctantly I went back to the amp circuit and decided to have another look at everything on that side of things. At this point I thought I had an idea of what channel was causing the problems, how to make the system stay on for more than a second, and what types of voltages I should be expecting to see on some of the traces coming from the logic board. I got no where checking voltages because everything seemed like it was what it should be or the voltage would get lost in a diode or resistor. When this happened I'd take it out and check it only to find it was working fine so I'd put it back. I finally decided to take out the audio amps for the trouble channel and see if I could find anything wrong with them and see if the behavior of the amp changed any. The chips were A1962 and C5242. The amps didn't test as shorted when they were in circuit (and they never got warm during any of the power cycling) so I removed them and they still didn't test as shorted out of the circuit. For them I could only check them with my dmm since my component tester isn't able to test them, but they tested alright in diode mode with my dmm. I put all the components back in that I had removed except the amplifiers and turned it on again. Surprisingly the who system came to life and stayed on, again I didn't leave it on for more than about 5 minutes at a time just so I didn't damage anything. I thought I was in the clear until I felt the d2061 and the A1024 that corresponded with the amps I removed and both of them were just as warm or warmer than they were before, but none of the other transistors or amps were warm at all.

Currently this is where I left it alone for the night. I can't find anything else connected to these transistors that would be causing any of these issues, nothing is shorted to ground or any other power rails as far as I can tell from checking, and nothing else connected to the amps is shorted or testing bad. I'm at a loss for where to go next other than pulling every single component out of the circuit for this specific channel and testing it.

I know this was an info dump/long rant, but any and all help with this one would be appreciated. I'm not really sure where to go next with this one and I'd love to be able to get this one working again. Please let me know if anyone needs more info, more pictures, or datasheets for any of these components I've mentioned and thank you in advance for any help or advice.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

You really need a schematic, cannot make heads or tails what devices you're talking about.

Making assumptions about the board, what is the voltage between the bases of the D2061 and the other transistor facing the other way right next to it (I'll call it Qdunno1p), and what's the voltages of each of those transistors' base with respect to ground. I don't know where in the circuit the A1024 fits in, though my guess is that it's connected to the D2061's base.

That being said, make sure Qdunno1p is not shorted which may explain the heating. Really need device designators ... and the schematic ... but maybe I got a lucky guess.

[lotas]

Re: Onkyo HT-R510 turns on and then immediatly off

Onkyo HT-R510 Service Manual

[tibimakai]

Re: Onkyo HT-R510 turns on and then immediatly off

You will have to test all the components at that channel.
Usually, when I have a situation like this(shutting down right away), that means that it is a hard short somewhere, and the protection circuit is doing it's thing.
First, I test the final transistors for short. Most of the time, I find the offending two transistors and I just cut their legs. After that I turn on the receiver, and usually it stays on. I test everything else on it, to see, if there is video and all the functions are working.
After that, I test all the components at the bad channels, replace what is bad and test again everything. I see that you have variable resistors there(that is for idle current adjustment, that has to be adjusted, right after you have replaced all the bad components. I know, on newer receivers I have to use two 100 Oh,/1/4W resistors on each wire that connects to that two prong connector, near the final transistors. I don't know who it is done on yours, but most likely, in the service manual it will be mentioned that.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

Thanks lotas, did not even see that TO-92 in between the TO-220F's in the picture provided, but for now, not talking about that one. The Qdunno1p I mean would be Q6044 (KT B1369-Y apparently) that I thought was next to the Q6034 (KT D2061).

Is the "KT A1024" we're talking about Q5034? Suspecting so...

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

Thanks lotas, did not even see that TO-92 in between the TO-220F's in the picture provided, but for now, not talking about that one. The Qdunno1p I mean would be Q6044 (KT B1369-Y apparently) that I thought was next to the Q6034 (KT D2061).

Is the "KT A1024" we're talking about Q5034? Suspecting so...

The d2061 you are calling Qdunno1p I believe is Q6034 on the board and the A1024 is Q5034. This is all going off the notes I took of the thing I have on my laptop. I'm not going to be able to physically look at the thing again until probably some time late tonight.

Q6034 is the one that was getting hot initially and Q5034 is the one that was getting hot when Q6034 was removed.

Onkyo HT-R510 Service Manual

Thank you for the service manual. For some reason I have always had a harder time finding stuff like this on google than alot of other people.

[redwire]

Re: Onkyo HT-R510 turns on and then immediatly off

I found repairing Onkyo 636 that grounding through the back plate is needed for some boards. It kept powering down after a few seconds, on the bench. Added jumper clips from HDMI/RCA jacks and it stopped doing that. So check- if the unit is all apart, the boards all have continuity to circuit ground.

You can do comparison readings between channels (on diode-test, ohms etc.) to see if there is trouble with one channel. A few resistors are fusible as well.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

Keep in mind bad, shorted transistors (not leaky transistors) do not get as hot as it was before it died, so you'll need to keep cold transistors in mind when debugging.

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

Keep in mind bad, shorted transistors (not leaky transistors) do not get as hot as it was before it died, so you'll need to keep cold transistors in mind when debugging.

I think I found the culprit. The transistor next to Q6034 on the board (Q6044) was shorted and not getting hot at all. When I tested it in my component tester it showed up as two resistors. The part is a B1369 pnp transistor and none of the other ones in the power amp circuit are testing as shorted. I also checked out the amps that I pulled out and they are both testing correctly still so I think what was keeping it on after I pulled them was it disconnected the shorted Q6044 from the rest of the circuit.

You will have to test all the components at that channel.
I see that you have variable resistors there(that is for idle current adjustment, that has to be adjusted, right after you have replaced all the bad components. I know, on newer receivers I have to use two 100 Oh,/1/4W resistors on each wire that connects to that two prong connector, near the final transistors. I don't know who it is done on yours, but most likely, in the service manual it will be mentioned that.

There is a section in the service manual about adjusting the variable resistor and what the values should be after replacing components. Thanks for mentioning it though because I probably would have forgotten if you hadn't mentioned it and been really confused when it didn't work.

I'll have to order up some equivalent transistors and see if they fix it. I don't seem to have any lying around that are the same or an equivalent.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

Yep that's the exact transistor I was thinking all along in posts 2 and then after getting schematic, post 5. Hope that it's sufficient to repair it, as it's still kind of odd that one failed without the A1962 failing with it... but who knows...

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

BTW you probably can toss in a TIP32A for the B1369 for a quick check, not as good as the original but should be functional.

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

Yep that's the exact transistor I was thinking all along in posts 2 and then after getting schematic, post 5. Hope that it's sufficient to repair it, as it's still kind of odd that one failed without the A1962 failing with it... but who knows...

Just got some 2SB872 in that looked like they would be compatible and it's still doing the same thing as before. I don't know if it's just compatibility with the parts I ordered or if it's something else at this moment. That being said nothing is getting warm, no other chips are shorted, and the power still only stays on when the driver circuit board is removed.

I checked and double checked all the other transistors and nothing seams wrong with them. The issue only consistently happens when I have the driver circuit board installed. That board in and of itself is a royal PITA to check parts on though because of there not being any common ground on it. The only thing on it I could find was a ceramic capacitor on each channel that only had the number 4 underlined on it read as nothing on my component tester and I got no capacitance from it with my DMM. The capacitor is labeled as c5084 on the channel that had the blown transistor on it.

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

I did some more digging and found two 2.2ohm resistors that had gone bad and were reading 200+kohms. I replaced them and it is still shutting off immediately after I turn it on. The resistors that were bad were in the same channel as the blown transistor and none of the resistors in any other channel had gone bad.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

You should check the main output transistors for damage again. These transistors usually cause problems that cascade down the chain - have a hard time believing Q6044 would be damaged unless other transistors are also damaged.

BTW what's the voltage voltage of each pin of P6084 referenced to GND?

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

You should check the main output transistors for damage again. These transistors usually cause problems that cascade down the chain - have a hard time believing Q6044 would be damaged unless other transistors are also damaged.

BTW what's the voltage voltage of each pin of P6084 referenced to GND?

I just got a chance today to look at the thing again, got to love holidays with the family. The voltage of both pins of p6084 were -59 volts before it shut itself off, 0v at standby, and with the driver board removed they were also 0V. I checked the other channels as well and they also were at 0V during power on and stand by. The only thing I can see in the schematic that they are connected to that would be able to short to the -58V rail is Q6064. I double checked it with my DMM and it didn't show any shorts between the legs in diode mode. I did the same for Q6054 and didn't see any shorts.

I may just order some new Q6064 and Q6054 to see if they solve the problem. I found a pair of them for $4 on ebay so it won't break the bank for me if I do that. Before I do that though I'll probably pull the old ones out and see if that changes anything now that I've got the other dead/shorted components replaced.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

Is that with Q6044 removed? Speaker attached?

What are the voltages at all pins of Q5044, you can use any ground you can access easily with the black/- probe...

[redbaron1007]

Re: Onkyo HT-R510 turns on and then immediatly off

Is that with Q6044 removed? Speaker attached?

What are the voltages at all pins of Q5044, you can use any ground you can access easily with the black/- probe...

That was with the new Q6044 installed and no speaker attached. I have not hooked up any speakers this whole time I have been working on it.

The voltages for Q5044 are 0V on all pins at standby and -59V on all pins when I power the unit.

Edit: Forgot to mention there were no shorts on Q5044 when I checked it before and after I tested the voltages.

[eccerr0r]

Re: Onkyo HT-R510 turns on and then immediatly off

Could you measure the voltages with one decimal point of accuracy?

As of right now things don't make any sense. Ensure R5134 is intact but hard to imagine this failed, and still bettery yet explain the large negative voltage on Q5044's collector if Q6044(and Q5044 itself) is/are not shorted.