Onkyo M-504 problem eeek
Hello, I hope I have this in the right place. I have an onkyo integra m-504 power amp. The one with the dual monoblocks in one chassis. Everything lights up except the servo operation light, the meters are peaked at the 500 watt place, no sound output, and I can't hear the relays kick. When you leave it on the heatsinks still warm up and looking through the vent holes on the top you can see eight red led lights. I just got it and I can only hook up my ipod to it and use the ipod as my volume contol (doesn't work so well since there is no sound output lol). Does anyone think they might know what is up and help me out? Any help is greatly appreciated!
Dan
Hello, I hope I have this in the right place. I have an onkyo integra m-504 power amp. The one with the dual monoblocks in one chassis. Everything lights up except the servo operation light, the meters are peaked at the 500 watt place, no sound output, and I can't hear the relays kick. When you leave it on the heatsinks still warm up and looking through the vent holes on the top you can see eight red led lights. I just got it and I can only hook up my ipod to it and use the ipod as my volume contol (doesn't work so well since there is no sound output lol). Does anyone think they might know what is up and help me out? Any help is greatly appreciated!
Dan
I figured something else out though. If you turn off the amp the meters stay pegged at 500 watts but if you also unplug the amp from the socket the meters slowly drop back to the bottom end. If you then plug it back in the meters stay at the bottom until you power the amp up. They then go back to being pegged at the 500 mark. I hope this helps. Oh and I forgot to say thank you kevinkr for your input.
Dan
Dan
There seems to be a problem with the protection circuitry. If you are not familier with electronics it would be best to have a qualified service man take a look. If you would like to know more about the innards, the schematics can be down loaded at: http://www.hifiengine.com/manuals_type.php?man=Onkyo&mod=M-504. Good luck.
How can you tell the amp is fried? I did a google search and a guy was having somewhat the same problems and everyone on that forum suggested the protection circuitry also. Well how much am I looking at replacing if the amp is fried, which is a bigger task the amp or protection section? If I had it professionally done how much am I looking at?
Thanks
Dan
Thanks
Dan
I think the protection circuitry is doing its job and the amplifier has a huge dc offset on the output stage. The clue is that the meters are pegged - it could be that there are internal fuses and some are blown.
I doubt the meter and protection circuitry share much common circuitry other than power supplies. (low voltages ones at that) So it seems more likely that the monitored power amplifier circuits or some of the power supplies feeding them are the culprit
Take a careful look.. Read the safety threads here before you do ANYTHING!
Do not touch anything before checking to make sure that the supply capacitors are discharged. (Assuming you have a meter and can recognize them.)
It may be that there are some blown fuses on the one of the supply rails. Replace them with exactly the same type, but do not, I repeat do not just plug that amp in and turn it on - more damage may ensue.
Instead wire a lamp socket in series with one side of an extension cord to make a ballast lamp. Install a 100W bulb, and have a 200W bulb on hand. Plug amp into ballast lamp cable and turn it on, if the lamp dims after a few seconds turn off the amp and replace with the 200W bulb. If with the 200W bulb the meters return to 0 and you can hear the relays click measure to check and see whether there is dc on the amplifier outputs. (Should be less than 100mVdc typically.)
If you don't have a meter, don't know how to use it, either consider making the seller eat it or make them pay for the repairs.
Did you get it on eBay and if so did you use Paypal to pay for it? IF you did eBay and paypal will take care of getting you your money back. Silly for you to attempt to go beyond this point as it may cost you a lot of money to get it repaired.
I doubt the meter and protection circuitry share much common circuitry other than power supplies. (low voltages ones at that) So it seems more likely that the monitored power amplifier circuits or some of the power supplies feeding them are the culprit
Take a careful look.. Read the safety threads here before you do ANYTHING!
Do not touch anything before checking to make sure that the supply capacitors are discharged. (Assuming you have a meter and can recognize them.)
It may be that there are some blown fuses on the one of the supply rails. Replace them with exactly the same type, but do not, I repeat do not just plug that amp in and turn it on - more damage may ensue.
Instead wire a lamp socket in series with one side of an extension cord to make a ballast lamp. Install a 100W bulb, and have a 200W bulb on hand. Plug amp into ballast lamp cable and turn it on, if the lamp dims after a few seconds turn off the amp and replace with the 200W bulb. If with the 200W bulb the meters return to 0 and you can hear the relays click measure to check and see whether there is dc on the amplifier outputs. (Should be less than 100mVdc typically.)
If you don't have a meter, don't know how to use it, either consider making the seller eat it or make them pay for the repairs.
Did you get it on eBay and if so did you use Paypal to pay for it? IF you did eBay and paypal will take care of getting you your money back. Silly for you to attempt to go beyond this point as it may cost you a lot of money to get it repaired.
No I picked it up from goodwill for 10 bucks (mint other than this) and figured if it didnt work it would be fun to play with and still a good deal. you said to plug the ballast into the amp, where at exactly? The speaker terminals? I have a digital multimeter, should that work as far as measuring the dc current? I don't really want to give up on this because I want to learn how to fix amplifiers, read schematics and the such. I also don't want to break this thing any more than it is because I want to use it. I'll check to see if a guy locally will fix it in trade for other audio equipment if I can't figure it out. I'll have to open it up a little bit more.
Thanks
Dan
Thanks
Dan
saabracer23 said:
Hi Dan,
Without being mean I think you are in perhaps just a bit over your head here. The ballast lamp is meant to be plugged into the wall, (it uses an extension cord after all) and the AC power cord of the amplifier is then plugged into it. This is intended to provide some protection to expensive components like the power transformer and power transistors in the event that there is something seriously wrong with the amplifier. (Which there obviously is.)
Note that I said to measure dc voltage NOT current.
Since you paid only $10 for this amplifier, and it was donated in none working condition your best recourse is to return it for a refund. With your current level of knowledge you are not going to be able to repair this. One other possibility would be to sell it on eBay or here as a none functional amplifier needing repair - Integras are worth good money and someone might pay you a decent sum of money for it. I don't recommend you even open it at this point, the internal voltages in this design can be lethal by virtue of the output power rating. Hopefully you can find someone to fix it for you if you do keep it.
yea good idea. I can't return it because of the as-is no refund thing but I don't want to return it anyway. I'll see if I can find someone to fix it. If you had to guess at 45 dollars an hour labor what I might be looking at as far as fixing it. If thats a stupid question with infinite possibilities then I apologize.
Thank you
Dan
Thank you
Dan
saabracer23 said:
Hi Dan,
No, that's not a stupid question at all. I really can't venture a reasonable guess as to what it might cost to fix, it could be a very inexpensive fix or it could end up being astronomical as in the many hundreds of $$.. Don't take it to just anyone though, find someone who is qualified to do the repairs, provides a repair cost estimate once they have opened up the amplifier - and before they do the actual repairs, and is either associated with an Onkyo dealer or is recommended to you by someone with relevant experience. Find out whether or not they will at least attempt to source Onkyo OEM parts if available and what they will do if they are not. An Onkyo service center might be a safer bet - although my experience with a competitor's service center was very negative so YMMV.
Make sure they burn it in for 24 hours after repair to assure it is reliable.
You may be better off just selling this amplifier and buying a good used amplifier that actually works. The likelihood of this amplifier being repaired correctly is not all that high.
both meters peg? And it's true dual mono? Then, it's gotta be a common circuit. Not much in there that's common. I'm guessing the outputs might, just might be fine. What's left that's common on these amps, guys? It could be the protection circuitry. It's not that common to blow both channels on a dual mono amp, at the same time. Might be water damage.
But then again, maybe someone's been in there already and the input board for the controls and switching are disconnected. Both inputs floating high. Some folks design their gear weirdly. bad Idea to build the input/loop circuitry like that, but the Japanese stuff can be strange like that. As in:Input/level/switching/lop circuitry all one board, for both channels. Only the two-stage amp is actually seperate and dual mono.
Anyway, figure $100-250 for the repair. Might be nothing but a dirty ribbon cable, though. Technics had a bad habit of building their better stuff like that.They could have balanced input stages on separate boards, with common power supplies and then going to the separate two stage output section.
But then again, maybe someone's been in there already and the input board for the controls and switching are disconnected. Both inputs floating high. Some folks design their gear weirdly. bad Idea to build the input/loop circuitry like that, but the Japanese stuff can be strange like that. As in:Input/level/switching/lop circuitry all one board, for both channels. Only the two-stage amp is actually seperate and dual mono.
Anyway, figure $100-250 for the repair. Might be nothing but a dirty ribbon cable, though. Technics had a bad habit of building their better stuff like that.They could have balanced input stages on separate boards, with common power supplies and then going to the separate two stage output section.
Ok so I showed the amp to my father and he said he could almost be sure that it is the smaller transformer staying open. There are three transformers and he believes the smaller of the three is somewhat of a regulator for the other two. That is why both meters are peaking, because of the dc voltage. That is how in a way he put it, I hope I didn't butcher it too much. He wanted me to ask you guys about it before I jumped on it (it would be a cheap fix, he knows a guy that can rewind it, or get me a new one as long as the value is on the trasformer). Let me know what you guys think.
Thanks
Dan
Thanks
Dan
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