onkyo ht-r290 - My Next Project

[SolomonMan]

All,
Before we get started I would like to thanks everyone for reading this post and for past help.

A few years back I picked up a Onkyo ht-r290 on eBay as a project and I am hoping to get it running again as a Garage Stereo amp so I have some tunes.

Ok so the symptoms, not plugged in to anything other than a power source.

I turn it on I hear a click and it basically shows the display and it quickly appears to power down.

If you click it a time or two (or three) you will definitely get something hot and I can see a extreme tiny amount of smoke. (So this is something I have only done maybe 2-3 times). The smoke appears to be coming from mid-front of unit.

Anyways before I start digging into it is this unit known to have any common faults.

Thoughts?

Thanks
Chris

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

All,
I hope this finds everyone well.

I have found the schematic for the unit online (moved it to my google drive).

https://drive.google.com/file/d/1ZUq...ew?usp=sharing


I am thining I am going to start at the power side of things.

I am going to get some images of the unit up online hopefully this morning but the cell phone is dead after the Holiday feast.

Would one start (a good place to start) off by removing the power connections to the other boards in the stereo to see where the fault may be located?

Thanks
Chris

[tibimakai]

Re: onkyo ht-r290 - My Next Project

I would start at the amp section. Try measuring the final transistors, on the big heatsink, to see if you find one(or two), that are shorted.
First, you should look around for obvious blown parts, to narrow down the problem channel.

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

I would start at the amp section. Try measuring the final transistors, on the big heatsink, to see if you find one(or two), that are shorted.
First, you should look around for obvious blown parts, to narrow down the problem channel.

tibimakai,
Thanks for the response!

I will take a look at the final transistors and the two other Mosfets I see in the system. The capacitors do not visually look bulged or leaking.

I was about to dig into this unit more when I decided to plug it into the wall again. Keep in mind this thing has been bouncing around my garage for 3 years and it was not until this posting has it had any power to it.

Out of the blue when I plugged it in I got the "CHECK SP WIRE" outlined in the troubleshooting section of the user manual.

https://www.intl.onkyo.com/downloads...manual_e01.pdf

Upon plugging it in I now get responses from the LCD screen that last more than a second. It now will allow me to interact with it for maybe a second or two before shutting down.

I am thinking I am going to try; (directly from the user manual - troubleshooting)

"The protection circuitry has been activated.
Remove the power cord from the wall outlet
immediately. Disconnect all speaker cables and
input sources, and then leave the AV receiver with
its power cord disconnected for 1 hour. After that,
reconnect the power cord and set the volume to
maximum. If the AV receiver stays on, set then the
volume to minimum, disconnect the power cord, and
reconnect your speakers and input sources"

I am going to need to find a couple speakers as well as currently I had nothing attached as I was not getting anything worthwhile from the system till the "CHECK SP WIRE".

Anyone seen anything like this before?

Thanks
Chris

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

Sorry for the Delay,

Below are some images of the stereo amplifier in question;

Thanks
Chris

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

All,
I have taken a small video of the current state of the amplifier and moved it to my google drive;


https://drive.google.com/file/d/19rL...ew?usp=sharing

Thanks
Chris

[tibimakai]

Re: onkyo ht-r290 - My Next Project

You have a short at one of the channels, that is why is shutting down. It protects itself.

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

You have a short at one of the channels, that is why is shutting down. It protects itself.

tibimakai,
Thanks again for the response!

As I am a complete novice...Can you elaborate on "You have a short at one of the channels".

Is that a specific location on the amplifier or is it what you mentioned previously on the "final transistors".

I probably will get longer to look at the unit more towards weekend. The early Ohio snowstorm caused me to have a few more farm chores this week than expected.

Again Thanks,
Chris

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

tibimakai,
I did a little research on "Channels" and thought about what you said a little more in your last posting....So please correct me if I go "astray".

So this is a 5.1 Surround system.

I believe its a 6 Channel system as it can except up to 6 speakers.

Would a good starting point be starting at the speaker connections.

Would finding a ground pad on the speaker connection board and checking resistance on each... possibly tell me which of the speaker (channels) is of issue.

Then work my way in from their to find the short/shorted component?

Thanks
Chris

[frankusb]

Re: onkyo ht-r290 - My Next Project

The two big black integrated amplifiers on the heat sink (in your 4th picture) is where I would start. Can you get the part number off of them?

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

The two big black integrated amplifiers on the heat sink (in your 4th picture) is where I would start. Can you get the part number off of them?

frankusb,
Thanks for the response!

I will try to get a better image of them tonight and post them ASAP.

Again thanks for the response,
Chris

[tibimakai]

Re: onkyo ht-r290 - My Next Project

I'm not familiar with Onkyos, with integrated amps. BUt most likely one of them has an issue.
The schematic shows three integrated amps, you seem to have only two. So maybe yours is only a 5.1 channel receiver.
2 x STK-442-730-E and 1 x STK442-530-E
You should have a 730, and a 530 in there.

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

I'm not familiar with Onkyos, with integrated amps. BUt most likely one of them has an issue.
The schematic shows three integrated amps, you seem to have only two. So maybe yours is only a 5.1 channel receiver.
2 x STK-442-730-E and 1 x STK442-530-E
You should have a 730, and a 530 in there.

tibimakai,
I am fairly certain its only a 5.1 as there is a "laser" engraved section of the bezel (its hard to see) that says its 5.1.

Looking at the components they seem reasonable at about $20-25 each new to my door. Might be after the first of the year before I receive them as many are coming from overseas.

Most that I am finding do not have that final "E" for example just the "STK-442-730" or I will find "STK-442-730N-E". Is there any big difference?

Having some trouble locating a Datasheet...

From my images it looks like there is some cooling transfer paste being utilized as well.

I guess the question I am still pondering is how to confirm the bad one 100%...hope the datasheet will give me a direction.

My plan is to start at the speaker connections and work back to rule out other issues prior to the final amp ICs...Then if all is good to that point and I have a Datasheet test the final amp ICs.

I remember in my research that there were statements that most of todays amplifiers are very similar except for the "features" or feature boards. Basically that all amplifiers are similar in amplification. I believe I am starting to understand what they were stating.

Thanks again for the help,
Chris

[frankusb]

Re: onkyo ht-r290 - My Next Project

I would guess you could tell by heat which one is bad. Power it on and one will likely be hotter than the other. Another thought would be to lift Vcc+ and Vcc- off one then both until the system stays on.

[tibimakai]

Re: onkyo ht-r290 - My Next Project

If there is an error, the receiver protects itself and the speakers won't be turned on. There are a few relays, close to the transformer at the back, that do that.
I would check those 0.22 Ohm resistors, at the legs #4 to see if they are open.

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

Guys,
Thanks for the responses I really appreciate it and I have learned so so much!

I will check the .22 ohm resistors and the temperature of the Amplifier IC.

I was hoping to get to it last night or possibly tonight but family chores (have 5 kids and a wife) has kept me hopping all this week...not to mention the earlier weeks snow. Tonight does not look any better, its grocery night (lol) but I believe Saturday (since I did groceries tonight) I can squeeze some time in for this endeavor.

If the one or both Amplifier ICs appear hot will removing them entirely still allow the Amplifier to stay on? (Is this kind of a standard testing protocol for amplifiers?)

If it turns out to be a single Amplifier IC would one normally just replace one or both? (How likely is the other to fail?)

I actually located the IC for about $15 new so if there is any benefit I may just replace both. Or maybe buy 2 and keep one as a spare if the chance of it not being available is ever a possibility.

On the relays, I included a image, I assume they are the large black items circled in green. I am looking for red, red, silver (.22ohms) resistors to test as well...correct?

Thanks again for all the help,
Chris

[tibimakai]

Re: onkyo ht-r290 - My Next Project

It is hard to believe, that in those few seconds being on will heat up.
I would replace only the bad one.
Usually, when I have a shorted channel and find the offending final transistor to be shorted, I just cut their legs, to get rid of the short and the receiver turns on and works great, except that channel.

[P Smith]

Re: onkyo ht-r290 - My Next Project

duh... a solution ... I would replace it and use the AVR fully functioning

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

It is hard to believe, that in those few seconds being on will heat up.
I would replace only the bad one.
Usually, when I have a shorted channel and find the offending final transistor to be shorted, I just cut their legs, to get rid of the short and the receiver turns on and works great, except that channel.

Thanks for the information!

The plan is I will get on the amplifier first thing in the morning.

Thanks,
Chris

[SolomonMan]

Re: onkyo ht-r290 - My Next Project

Guys,
I got a little time on the amplifier last night and this morning.

The Amplifier ICs do not appear to be getting hot in the least. I ran it thru the ON and then protection OFF "process" a full six times (right after each other) with the amp full up volume.

Images are included of the actual ICs.

They are a pair of STK443-530.

I was going to tear things down and try to start troubleshooting the electronic components but I am going to ask for a little guidance on the tear down part. (To avoid breaking things/time reasons)

How does one normally tear down a Amplifier or specifically a Onkyo Amplifier?

Does the bottom come off some way or do you just strip it down board by board to the board in question. The reason I am asking this is I have seen a couple examples on YouTube where they are replacing the ICs and they just took off the bottom (Somehow) of the stereo unit to desolder and resolder in a new set.

Also I have include a image of a set of connectors (Yellow Square) that are numerous on this unit. It appears they are power connectors.

I am going to mention, for anybody in the future that has to tear this unit down, they disconnect by pushing down on the white center on both sides and gently pull the wire(s) up.

It took me a little while on this as I have not seen this connector before but luckily I took my time to figure it out. (read here no damage)

Thanks everyone for the help,
Chris