Onkyo m-504, m-508, and m-509 repair/upgrade, conundrum/problem.

ScottO13

New Member
Hello, I have been looking for a more musical amp set up than the Rotel RB1080's I've been using. The cost being prohibitive of anything that I'd want new, it just so happens that I love vintage gear anyway! Having purchased already one of each, Onkyo m-504, m-508 and m-509. I have the habit of taking vintage gear into the shop for servicing "This gives me a 30 day warranty on anything I buy!". I found out pretty quickly that none of the older amps had binding posts that would accept banana plugs. So when I took the 504 in first for service, I showed up with shiney new insulated binding posts. I was informed that they couldnt be used. That the 504's had two four place terminal holders on a "plate" that screwed in to the frame. The service guy called Onkyo to try to get a new set-up and was told that there was NO replacement.
Since I refuse to believe that this cannot be done I've since researched for a bit online. It has indeed been done. Most made it sound very difficult and involved. But two people stated that they had done this quite easily but did not state how. The problem with the posts is that they are all quite old. Dead in fact. So I'm hoping that someone knows something about this. I know that I could just leave them alone. But the m508 has one that is broken anyway.
Also I have a question about recapping these if needed. Would it be easier to recap using "4" larger caps rather than fabricating all you need to for the eight orig. Caps?
I am a huge fan of these amps with how they sound. Any help or advice would be highly appreciated.
Thank you, Scott
 
Also, does anyone know how to remove the original wood side panels from the m509? It should be exactly the same as the m510. Unlike the m504's which have screws that are apparent. The m509 has no such screws that you can see. And screws from the inside just make no sense. The vinyl veneer covered mdf is bubbling from humidity and age. I am going to make new, real maple panels for all three!
Thanks Scott
 
If like the 510 as mentioned, you'll have to remove the top and bottom covers. The bracket mount screws are right there to see once you're in there.
 
You can create your own banana plug jumper set that can just live with the amp, making it easy for swapping etc. I would love to have your three problems. Would you please clarify your questions regarding the caps. It appears you might be discussing the filter caps, as there are more than eight caps to consider. What is your need?
 
Not sure about removing the panels on the 509 ( i knew there was a 510, but didnt even know a 509 existed), but your comment sparked a memory. Years ago when i had the M508 and P308 and also an onkyo cd player (cant remember model, but it did not have the wood panels), i built and installed panels made of white oak and stained to match my JSE model 2a's, and it made for a really nice looking settup.
 
Not sure about removing the panels on the 509 ( i knew there was a 510, but didnt even know a 509 existed), but your comment sparked a memory. Years ago when i had the M508 and P308 and also an onkyo cd player (cant remember model, but it did not have the wood panels), i built and installed panels made of white oak and stained to match my JSE model 2a's, and it made for a really nice looking settup.


Since two of the amps came missing panels and the m509 had damaged panels, I decided to make new ones.
Instead of the original mdf with vinyl veneer, I am going to use Curly "Tiger" maple. The m504 and m508's panels are the same and done except for the dye, "Amber or maybe blue to match the new LED lights I had installed", And laying down the urethane finish.
So the panel mounting screws are visible looking up or down with the covers off? Wow.
And thanks for the help.
 
Note that the panels for the 509/5090 are quite different from the other integra/grand integra line in that there is a vent panel taking up about 40% of the lower portion of it.
IMG_1103.JPG
 
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You can create your own banana plug jumper set that can just live with the amp, making it easy for swapping etc. I would love to have your three problems. Would you please clarify your questions regarding the caps. It appears you might be discussing the filter caps, as there are more than eight caps to consider. What is your need?
I am wondering after reading online about re-capping "replacing" the 8 main capacitors. There was a thought posed that it might actually be better to replace the original caps with just four much larger caps. The reason being that the pins were all assigned and the cap custom built in an archetecture that was abandoned for maybe design flaws. "Thats guessing on my part". But four replacement caps kinda make sense after hearing about all the fabrication done to upgrade these amps.
 
Replacing 8 with four will take a good bit of rearranging the frame. Is there space available? There will also have to be some math done to decide if it can be done. I wish you some luck.
 
Great! Thank you so much! as they say, "A picture is worth a thousand words". I am taking it in for service Monday anyway so now I can get the old panels off beforehand and use them as templates for the new "real maple" ones I'm making. I'll post some pics when I get done.
Yeah squealer The only differences from what I've found between the M-509 and M510 are 40Lbs. more copper in the M-510's power supply and the fact that the m-509 is black.
Uh oh, I'm NOT trying to be racially motivated or,........um, anything here. .but, The m-509......It's definitely a "black thing". And OF COURSE in a good way.
The only model more rare is actually the much lauded M-5089 which I am currently trying to hunt down. at least everyone's 'heard" of the M-510. Just outta my price point at around $9,000.00. Per the one that sold on Ebay last week. "The one the week before went for $6,500.00!
I love this amp, I just hooked it up yesterday. The gigantic meters make it so easy to see that I'm using about 9 watts on average, Pretty LOUD!
Thanks All!
Now if I could just figure out what to do about the wonky Speaker binding posts that Onkyo put on all their m-503 to 510 amplifiers to save $0.03 cents on....
 
Replacing 8 with four will take a good bit of rearranging the frame. Is there space available? There will also have to be some math done to decide if it can be done. I wish you some luck.
there iS some space available for larger caps. Especially vertically. I'll measure Monday. By utilizing a larger four caps it was summised that the power rating could be upped as well.
 
I have a M-508 and it looks like on the side of the binding post, it can take some banana plugs. I'll try it in about 15 minutes or so to let you know.
 
I looked at all of mine from the side of the posts and there didn't look to be enough room for banana plugs I didn't think. I thought about "forcing" the old red and black plastic nuts off but I know someone that tried that and the metal stud broke off at the amp case.I WAS going to try to find a mini binding post "which I did" but the 6-32 thread looks about the same size but a different thread geometry.
Onkyo support is worthless for vintage gear. The guy there seemed to be trying to give me a complex about my old gear. He just wouldn't quit with the "But our new AVR will....". I'll find a way to replace those old wonky binding posts. I know that it's been done before. I just do not know how. AND I need "4 place", in a row plastic replacement binding post holders if I break or damage them trying to modify them. You cannot just drill them out and replace them evidently. There is a stud on the outside that the plastic post screws onto that ends in a metal plate "Tiny and round" that is surrounded by the four place block/barrier..My service guy said he couldn't take the blocks apart. Like they were molded or epoxied together. And there's no way to use two dual binding post spacers because they have to be screwed or bolted at each end so using those would leave the inside end of the four swinging in the wind.
 
image.jpeg It really looked like it was going to fit , and it does to an extent. Won't be secure, I'm assuming it makes a connection (only have banana plugs because the binding posts on my speakers are too small for the speaker wire)
 
Hee hee, Never seen an m-509? I have three but two need allot of work!
Deeztip, they will "kind of" make a connection. The kind that might cause some damage to your amp I believe if you leave them there and try to amp whatever comes through..
Please remove those, yer makin me nervous!
 
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