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Panasonic SA-HE200 AVR - "Overload" condition fix

Discussion in 'Troubleshooting and Repair' started by Tesla, May 10, 2010.

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  1. Tesla

    Tesla

    165
    2
    May 10, 2010
    I have a Panasonic SA-HE200 6.1 AV Receiver (circa 2003) . I think this is the last model before they then went digital and got smaller. It’s been on the shelf un-moved for years, but we use it any time the plasma is on (everyday for hours at a time). It has 6 good sized JBL bookshelf speakers and an Infinity sub connected to it.

    We were watching TV one night (at normal volume) and all of a sudden the sound went off and OVERLOAD scrolled across the display. I turned it off for a few minutes and when I turned it on it said “Overload … Turn off receiver”. I turned it off for about 10 minutes while I unplugged the surround speakers, the (powered) sub, and the center speaker (just the L/R JBL 26ii speakers and a few components hooked up).

    It came on and played fine, but a few minutes later it said “Overload” again. I unplugged everything and turned it back on about 15 minutes later … it still said “Overload”.

    I put it on my workbench and removed the cover. By now it had been un-plugged for about 30 minutes. When I plugged it in it still said “Overload” (and the fan comes on) with nothing hooked up to it. It was very clean inside. I went ahead and checked the fuses and cable connections inside.

    It wasn't dirty inside, but went ahead and blew it out. I noticed that the heat-sink compond on the MOSFETs is still moist. A day later I finally got it to come back on, but it would only play for about 10 minutes before going into an Overload condition.

    Now (2 days later), the AVR would go into an Overload condition about a second or two after turning it on (when the main output relay would normally click closed ... which wasn't happening ... no output at all).

    It turns out the schematics for the Panasonic SA-HE200 are easy to get on the internet.
    http://www.eserviceinfo.com/downloadsm/40404/Panasonic_SA-HE200.html

    There are 2 large MOSFET power transistor ICs (RSN310R37A) mounted to the main heatsink. The 6 channels are split between them. The chances of both of them going out at the same time are slim (it's probably one or the other). Panasonic made it easy to unsolder them from the bottom of the main board without pulling the board out.

    If you compare the voltages on these 2 chips, you should see one with unusual voltages (around the middle) PINS 12,13,15,16. Those deal with the Internal Overload condition of the chip and if ok, giving the ok to turn on the main relay on the speaker outputs.

    Pin 10 just helps turn on the fan as needed. Pin 12 of ic601/602 is the real Overload signal. They go to pins 3-4 of ic901 (the main CPU).

    In my case, it was IC602 with the weird voltages there. It was also the cooler one to the touch (even in Overload) while IC601 (the other good/working MOSFET of the pair) was hotter. It was as if the bad one bad shut down completely.

    I know that you can sometimes remove the bad transistor or regulator and it will stop blowing fuses. Keeping that in mind, I removed IC602 and powered it up. Now, instead of immediately going into Overload state, the amp powered up more normally.

    I could play my MP3 player into various inputs and the left channel of the headphones work. This is because they split the main L/F channels between the chips. I could change inputs, DSP modes, use the radio tuner, etc.

    The main speakers did not work yet, but this is not really surprising because the main speaker output relay doesn’t click on. I think it can tell that one or more channels are down and refuses to activate (which is expected).

    So, now I knew a lot of boards were working fine (particularly the Power Supply, Main Logic/DSP board and the main CPU/Display/Control boards). I also tried various inputs (some on the main Power Board) and they all worked properly as well.

    I HAD NOT seen Overload since I removed IC602. I tried not to push it too hard because the output is “unbalanced”.

    I replaced ic602 with a new one. I had to get it from Canada.
    http://www.richtechparts.com/i-1550-RSN310R37A.html

    It works great now.

    Of course, I had to clean off the old and replace the silicone heat sink compound on the new MOSFET, but while I was in there, I also replaced the silicone on the un-blown or still good ic601 MOSFET. I'm glad I did and here is what I noticed. With the old (but still pliable) silicone the front of the MOSFETs themselves would get very hot. When cranked up, the fan would come on but they and the large heatsink would still stay very hot.

    With the new silicone on both ... the MOSFET fronts stay cool and all the heat is properly transferred to the heatsink (which still gets really hot). However, now when the fan comes on it cools the heatsink down drastically.

    It amazing how much better the thermal management works now with the new silicone. I think that the inability of the old silicone to dissipate the heat from the MOSFETs, might have lead to the premature failure of the one MOSFET. It also seemed to have also kept the heatsink/ fan system from working properly. This turns out to be similar to how old silicone can allow your computer's processor to overheat and even burn-out (even if the fan is still working).

    As for the silicone, the next time you are servicing your nice high-end amp., you might think about re-siliconing the power transistors. It's like maintenance on your car. It's all about being pro-active ... before something blows up. I used GC Electronics - Type Z9 - Heat Sink Compound (Silicone Base). A 1oz. (30ml) tube was around $10 at the local electronics supply.

    This is as far as I had to take it apart. This picture was taken right after I had taken it apart (old silicone still on all the parts). Try not to run it or check voltages without the heatsink installed. If you do, make sure it turned down super low and be quick. I had to move the transformer and PS Board to get to the screws on MOSFET ic601. I reinstalled them temporarily before turning it over for soldering. Silicone it and screw the new MOSFET to the heatsink half before installing it for soldering. Apply the silicone thinly and evenly, but don't get any on the pins (only the metal backing).
     

    Attached Files:

    Last edited: Dec 4, 2010
  2. Tesla

    Tesla

    165
    2
    May 10, 2010
    So, I did this repair about a year ago, and the amp still works fine. I currently have 5 speakers attached.

    I also posted this in another forum and another user had the same amp with the same problem. Using this guide, they also replaced IC602 MOSFET and it brought theirs back to life as well. Therefore, it appears to be a trend failure.

    A couple of months ago (armed with some ear-plugs) I turned it up to 95% volume and let it play for about 15 minutes. Sure, the fan turned on and it was pumping out the heat, but it had no problems.

    Not a bad amp ... It decodes AC3 DD5.1 DD-ex6.1 and DTS, optical and coaxial inputs, and goes to 600 watts.
     
    Last edited: May 14, 2010
  3. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,448
    2,809
    Jan 21, 2010
    Potentially useful information. I note that when googling I often have hits to this forum so you may have helped someone who has the same problem in the future.
     
  4. keine

    keine

    7
    0
    Jul 15, 2010
    Wow Tesla, you are a savior.

    So I also have the SA-HE200, and I also have the overload problem. Mine seems to be an overheating type problem as the receiver will play fine for a bit, but after awhile I will get booming/popping through the speakers and then OVERLOAD on the front screen of the AMP.

    However, to fix the problem, I took a 12V wall wart and plugged in a new fan (92mm I believe) to the back. This fixes the problem, but it really annoying to plug in the wallwart AND turn on the amp everytime I want to do something. Running the 92mm fan at 12V is also quite loud. I've been doing this for a couple years actually I believe. However, I have absolutely no need to replace this amp. Do you know what kind of voltage the stock fan originally ran at?

    What would you recommend TESLA? Should I do the silicone? I don't even know if my fan was turning on at all and thats why I replaced it manually. Is there some way to check if the fan being dead is the problem? Does that make any sense?

    (Some of the component inputs I believe have failed as well on this model, which I do not know how to fix, I believe on went greyscale, but thats besides the point.)
     
  5. Tesla

    Tesla

    165
    2
    May 10, 2010
    If you have caught it before the MOSFETs are damaged, the new silicone will definitely help the thermal control system (silicone, heat-sink, and fan) to work properly.

    Since you are going into Overload (and back out again) it sounds like the MOSFETs might still be good and are shutting down before any damage has been done (as designed).

    The fan is a normal 80mm 12vdc computer case fan. You could easily try swapping it out. In fact, I did in the beginning, but the silicone was the real problem and the MOSFET was already damaged. It didn't work any better than the stock fan back then. I put the stock fan back in ... working fine to this day.

    The way they designed it, it gets passively cooled (fan off) at low to medium output levels. I guess it's because it's a sound amp and you want it to be completely silent if possible. When you get up to 15 or so, the fan turns on (active cooling). At these levels, you couldn't hear the little fan if you wanted to. With good silicone, this all works fine.

    There are various things you could do with wiring the fan, but without good silicone on the MOSFETs, they will still get too hot because the heat from their back-plates doesn't get transferred onto the heatsink where it belongs.
     
    Last edited: Jul 15, 2010
  6. keine

    keine

    7
    0
    Jul 15, 2010
    I greatly appreciate the reply Tesla.

    What is sounds like to me, reading your reply and original post, is that I got on top of the problem soon enough by installing the new fan and running it all the time at 12v, to possibly override the bad silicone and save the Mosfets. As only if I do not turn the fan on, and do something for 30 minutes does the receiver go into overload and bork.

    I'm gonna try redo the silicone and put the original fan back on. The fan isn't broken, it just doesn't turn on till its loud, like you said, something I didn't realize. However, the silicone is broke.

    I live in a town without an "electronics" store per se. We do have a radioshack and I have access to many hardware stores such as Home Depot and Lowes. However, no Fry's or Microcenter..etc. Recommendations? Order it online?
     
  7. Tesla

    Tesla

    165
    2
    May 10, 2010
  8. keine

    keine

    7
    0
    Jul 15, 2010
    Well, I didn't have any compound as was mentioned. However, I did have some Arctic Silver 5. So I dug in and took out the heatsink without disturbing anything else. 4 screws on the Mosfets. 6 screws on the heatsink. Noting that a CLIP will pull off with the heatsink from two tinier 3 terminal fets to the front of the larger mosfets.

    Anyway, I scrubbed off ALL the mosfets with cotton pads and isopropyl alcohol, and moderately reapplied Artic Silver 5. I applied about 6 pea sized dots to each larger fet, and one dot to the smaller fets and reassembled.

    Now to just test for awhile I suppose. Its playing stereo music into VCR3 from an ipod at rather larger levels for about a half hour now, no problem. Stereo music from ipod was one of the most difficult things it used to have to do without overloading, due to the larger volumes needed, lower levels coming out of ipod compared to say Wii or Xbox.

    I'll continue testing. Maybe a full avatar movie inside the cabinet will tell.
     
  9. Tesla

    Tesla

    165
    2
    May 10, 2010
    Sounds good.

    Does your iPod have a real Line Level Out, or are you just using the headphone jack?

    Can you test it with a real AV component, like maybe a DVD player, outputting 5.1 via optical or coax SDPIF ? Even if audio has to go via Stereo RCA ... might be a better test.

    Did you put the old fan back in?

    Are you noticing the heatsink gets pretty hot, but the front of the main mosfets stay pretty cool now?
     
  10. keine

    keine

    7
    0
    Jul 15, 2010
    Last time I probed around in there while it was on....I blew a fuse. :D Was trying to find 12v or something for my fan. Little smarter in the way of power/circuits nowadays. but, I could check that yeah. (I was able to find a fuse and replace it!)

    I'll do some movie watching, full 5.1 DTS, and give it a test, yes.

    I actually just use a 3.5mm to an RCA L/R, and go into VCR3 with it.
    The heatsink is getting hot, as the vent on the top is escaping hot air after about 45 minutes of Ipod. Now that could still be the front of the fets, but I'm thinking no since its comes right off the top of the heatsink.

    And yes, I put the stock fan back in. I actually bought a crazy quiet Nexus 80mm to replace the stock, but it only came with molex and 3prong fan connectors. The fan connector in the SA-HE200 is a 2 prong, I believe just 12v and ground, since the stock fan reads 12v on its sticker. Not that it really matters how quiet the fan is, as it never comes up because I never push the amp to the volume levels which it would turn on. (Do you know the reading in dB that is the turn on point?)

    I really appreciate the input Tesla.
     
    Last edited: Jul 16, 2010
  11. Tesla

    Tesla

    165
    2
    May 10, 2010
    Yes, on a stock fan, just connect red and black wires the third and/or forth are for speed monitoring and/or control.

    Passive cooling (fan off) is fine most of the time ... However, if you want it to run all the time you could just run the wire outside, and just plug the wall wart into the amp itself on the switched AC Output.

    As I remember, the fan doesn't turn on until 10-15 but it varies depending on how many speakers you have hooked up (and are actually outputting sound ... using power).

    What's interesting is that even at 15 the heatsink is too hot to touch ... turn it up to 10, the fan comes on and the heatsink cools to luke warm (of course, this only happens with the cover on ... like it normally is.).

    I was asking about the iPod because ... while a headphone jack can serve as a Line Out, it's not really a "Line Level Output" (what the amp is expecting). If the voltage rises much over 0.5 volts ... that will throw amps. into Overload as well ... but it's "Input Overload" ... not Output Overload.
     
  12. keine

    keine

    7
    0
    Jul 15, 2010
    44 minutes into a DTS DVD film using 5.1, BOOM! POP! and I immediately turned the receiver off.

    :(

    I did have it in an enclosed under television cabinet of sorts. Possibly max of 2 inches between the receiver's top and a cabinet separation. Pulled it out and felt the top of the receiver and it was pretty dang hot. I bet the heatsink was too hot to touch, literally burning. I'm going to let it cool off and try again, with the receiver out in the open. Maybe I just can't have it enclosed as I do. At least finish up the movie I'm currently watching. Receiver is set at a setting of 49/50dB a pretty low setting.

    Wondering what now. What do you think is the next course of action? Back to the loud fan? Is the heatsink simply insufficient for these fets? Did I not use enough/adequate heat sink compound? I suppose I could go in and touch the fets to see if heat is being adequately transferred. Could this be a result of improperly hooking up the surround sound system? Improper speakers? Improper wiring? Improper impedance? Improper wires lengths? The fan never turned ON! :mad:

    If the receiver will still perform when cool, that means the fets are still okay correct? Its when it automatically goes into overload when the fet has gone.
     
    Last edited: Jul 21, 2010
  13. Tesla

    Tesla

    165
    2
    May 10, 2010
    Sorry it's still not working but yes, that is a better test.

    Closed cabinet? No, it has to breath ... you can't smother it :) 2 inches on top should be ok as long as the front is open.

    To see if the compond is working, you will have to run it with the top off and be sure the MOSFETS are staying fairly cool on the fronts. Don't worry ... it won't shock you but only touch their front cases. The new compound was completely covering the backs of everything attached to the heatsink, right? A thin layer just like a computer processor? I use the non-electrically conductive stuff. If you didn't, be especially sure none got on the mosfet pins.

    Those other things you mentioned all have to be checked but I assumed all those general AV things were checked before you started digging into the amp.

    No, unfortunately ... the fan doesn't work on temperature... it works on power levels. Too bad we can't adjust the "on" value. At those 50 levels, the heatsink alone should work (as long as it's getting some air).

    A standard 12v 80mm computer fan on a real 12 volt adapter should be pretty quiet. You could try a 9v DC power adapter or adjustable one to get the RPMs down a little. Screw it in the case, run wire outside and plug into the amp's switched outlet. Or maybe, you need a hole in the AV-TV cabinet (if the front must be closed) and put the constant fan there (leaving the amp's as backup).

    There is a place on the net that sells a temperature controlled fan and power-supply. I think the kit is $35 ... yes, here it is:
    http://www.coolerguys.com/840556090885.html

    ... I think they have a cheaper set with manual controls and they also sell the individual parts. Sounds like you might need something like this whether you stick with this amp or get another. My new Onkyo 607 really puts out the heat . I bought this for it (used also as a shelf, now I can put the center channel right on top)

    http://www.antec.com/Believe_it/product.php?id=NTE=

    Maybe one day I will hack in the CoolerGuys digital thermo. into the Antec (so it turns on and off) or just move the Antec to the Panny 200, and hack the whole CoolerGuys kit directly inside the Onkyo (still can't believe this thing has no fan). I think some of the new mid-level Onkyos do though (finally).

    I don't know if your MOSFETs are still good or not. I CAN let you that mine worked fine for over 5 years. Then, one day it went into Overload. It cooled down and worked for a day or so and then it kept getting worse until finally it went into Overload right away.
     
  14. keine

    keine

    7
    0
    Jul 15, 2010
    Thanks for the reply Tesla, I really appreciate it.

    So, I tried finishing up the DTS movie. Took the whole unit out and put it in the open. 38 minutes later, I had the same exact booming and popping. Man it scares the crap out of me. Anyways, I took off the top and felt the fets. They were pretty hot. Not burning, as I could easily keep my hand on them. However, the heatsink could not be touched.
    I took out the stock fan and put my Antec Stealth back in, plugging the 12v wallwart directly into the back of the receiver. (I didn't know this was even there! how convenient, wish I would have known.) Anyways, the problem did not occur of the rest of the movie, as expected.

    So the cabinet makes no difference. I suppose this boils down to a simple matter of heat. I do not understand how the heatsink can cope even as lower power levels without some sort of active cooling. The thing is literally burning hot. It cannot be touched. I don't know much about heatsink or conduction theory, but I could assume that if the heatsink is THAT hot, the passing of heat from the fets is working. I don't know if I could make it "work" any better with more paste. AS5 is slightly conductive, but I was pretty sure its not a problem. I was liberal but not oozing. On computer CPU's, a rice sized dot is enough for a core. I put 6 of those "dots" on each fet. I would venture thats more than enough, maybe even too much. I doubt the surface area of those fets is even 2 CPU's. The fets were pretty darn hot to the touch. but the heatsink was even hotter, like burning hot. I could certainly try again with more compound.

    Anyways. I'm thinking my heatsink is simply incapable of cooling the fets adequately without some kind of active cooling.

    I may be able to take the 12V down to say a "low" level (I forget what "low" is in PC chasis land), and that might adequately cool the heatsink. Buy a fan control, as Tesla said.
    I'm at a point where I really really don't need a new receiver. I have no use for HDMI yet (still perfectly fine with component and toslink.) In fact I flat out don't want one. I don't need 7.1 or anything like that. However, your Onkyo recommendation will stay in the back of my mind. (!)

    Thanks Tesla for the input again! Very much appreciated.
     
    Last edited: Jul 21, 2010
  15. keine

    keine

    7
    0
    Jul 15, 2010
  16. Tesla

    Tesla

    165
    2
    May 10, 2010
    It sounds like you know how to apply compound to a computer processor, and since this is no different, it's probably done fine. A thin layer on the whole plate is what you want. Be sure the screws are still a little tight.

    I'm only talking from repair experience with this one amp. Others might work differently, especially if your equipment or environment is slightly different than mine. It seems that most amps operate at a fairly high temp and is considered normal (just like video cards). Luckily the boiling point of silicon and silicone is much higher than water :)

    As long as you can still hold your finger on the mosfets, I also think heatsink is doing it's job the best it can. Without some air circulation, it can only dissipate so much heat.

    Yes, that variable controller should work. Here is another (but with less details about handling capacity, etc.)
    http://www.coolerguys.com/840556089537.html

    You might experiment with putting the fan on top, and maybe with pushing or pulling.
     
    Last edited: Jul 21, 2010
  17. Tesla

    Tesla

    165
    2
    May 10, 2010
  18. dairiki

    dairiki

    1
    0
    Nov 3, 2010
    Thank you!

    Thank you Tesla!

    I experienced the 'overload' failure. The first time, the receiver recovered after turning it off and waiting a bit. It happened a second time a couple of days later — this time no recovery even after a long rest.

    In my case IC601 was the culprit. I replaced that and all is fine.
     
  19. Tesla

    Tesla

    165
    2
    May 10, 2010
    You are welcome.

    I noticed yours died slowly as well, so that appears to be a common trait.

    So, that's 4 amps. (that I know of) that have been fixed by replacing either IC601 or IC602. As you know, they are the same part ... and it takes a little trouble-shooting to find out which one is bad.

    Good work.
     
  20. herrkelm

    herrkelm

    3
    0
    Dec 4, 2010
    Can't find IC601 or IC602 MOSFET replacement parts

    I went to the link referenced earlier on the Canadian website but did not find the parts. Are they still there or is there another place or part I can use to replace both MOSFETs?
     
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