Got this used system for my son to use at college. He brought it back, says the audio cut out and will not come back on. When I first got it, the sound cutout on me but came back on. Anyone know where to start to troubleshoot the problem. Cannot afford to take it in. Maybe it something I can fix.
I just plugged the unit in and you could hear a click inside when you powered it on but no lights or sound. There is a click inside when you power on & off. I jarred the unit and it came on and works. Will see how long it stays on.
First test, unit ran for over 2 hrs OK. Discovered sometimes it will turn on & off and works, sometimes needs to be tapped or switched off & on a few times. Sometimes sound will come from only one speaker until you repeat off & on or tap unit, then unit will work. Any help out there for the most likely cause?
patriot,
If I had too guess, there is a short or loose solder connection somewhere in the unit. Probably why it starts working when you hit it. Without looking at it, your guess would be as good as mine as to where it is.
Took the cover off while unit was working. In the middle of the main board there is an opening where a large "power module" (attached to large cooling fins) is located. It attaches to the board and the frame. I pressed on the module which deflected the board slightly which caused the unit to cut out. Another thing. There is a cooling fan. I don't know if it suppose to run all the time or has a thermostat. It has not come on while playing for 2 hours. I unplugged it and could not get any voltage readings from the board pins. Don't know if the fan is AC or DC or what voltage it is suppose to be. Can anyone tell me about the fan and how it is suppose to work? Please help.
Hello Patriot. I'm new to techlore.com, I *just* got my login ID so I can post this reply.
You and I seem to have >IDENTICAL< problems with our panasonic SA-H82's. I've had mine for years, and for a very long time I've noticed the same problems with mine that you have described in your post: The power light fades and flickers, the right channel (audio) goes out intermittently, and yes I hear a clicking sound from inside when this happens. And yes, I can give a good smack to the side of the cabinet and sometimes that works: the right channel comes back, the power light stabilizes, it works normally for a time, and all is well [ :) ]...
Here's what I found when I opened it today and took a look inside, and maybe this might help you, seeing as how this may very well be a 'common' problem with this particular model of Pana. stereo. In *MY* case, I found a resistor near the back of the unit, on the bottom pcb, which has "smoked." The part number is R818. The burning on this part unfortunately has obscured its color bands, so that it's anyone's guess what the value of this resistor is - If I knew that, I could replace it. (And once I replace that, I can continue on and properly make a determination as to whether that is indeed the cause of the problem.)
My thinking is, with our similar "experiences" with this pana. stereo, that maybe the R818 inside your stereo is smoked also.
Perhaps if you are so inclined, you can open your unit up and look for this part, see if maybe yours is a crispy critter also - any information in regards to this, I think, would more than likely help *both* of us out, seeing as how our experiences with this panasonic stereo are so remarkable similar.
Anyway, that's my input on it. Wish you luck.
~Blakat
'Addendum:' ...forgot to mention the fan....
Thought I'd make mention of this, since you're having problems with your rear cooling fan, and I forgot to address that -- suffice it to say that I'm having zero problems with the fan; it works. I'd also venture to say that this particular cooling fan is not as 'functional' as it appears... ie: it is only an exhaust fan, providing outgoing air flow across the large heatsink of (what I assume to be) the power amp(s) module. It's not physically 'married' to this heatsink, so what cooling it does provide is scant at best. There's also sectional grating in the stereo's bottom metal, to allow incoming airflow. It's a pretty typical arrangement for fan-cooling designs as far as that goes, but I'd hazard that the function of this fan is really just to exhaust hot air from inside the entire case, and not just the one power-amp-heatsink. I imagine that, if this fan were to stop working, the effect would be an increase in the overall interior ambient temperature of the case-- now, whether or not this heat increase is sufficient to cause component damage, I'd say Probably Not. (At that point it would depend on the ambient temp in the stereo's surrounding environment, your son's room in this case)
Anyway, that's all I can think of at the moment. GL to you.
~Blakat
The problems as described usually is because of a bad connection around the power amp module. Since this area is subjected to a rather large amount of heating and cooling during use, this is a common problem. This would account for the start and stoping of the sound. The burned resistor is another thing though. I have seen problems with the voltage regulators in these units which will cause higher current draw than typically expected. This would cause the resistor to over heat as it is usually a current limiting device (similar to a fuse). Repairing the bad solder joints in this unit and replacing the burned resistor should give you years of additional enjoyment.
Dan
The burned resistor is right next to the power amp module; I wouldn't be surprised if it was a load-bearer for the amp, or even a power sink for that matter. It's burned/charred, but at the same time, it doesn't appear to have physically "burned open." More like just cooked - still providing electrical connection (somewhat), just no longer functioning properly. It would be convenient if this was the case, because as you mentioned, replace this part + check the solder joints= longer life for my stereo, which would be Good. :)
The resistors in the unit are all gold-band 15-20% tolerance, however they are bluish-green which suggests they are metal oxide composite. Will be interesting to see just how easy it is to acquire one, given I ever find out what the proper value is ;)
~Blakat
Blakat,
I sold the stereo in a yard sale. I did advise the buyer about the problem and they bought it anyway. Sold it really cheap.
Thanks for you input. Sorry I could not help you.
Im trying to get a copy of the service manual for this unit (its not on the CDs I have). What is the amp pac number (it should be on the front of it)? Also, if you can see where the resistor connects? Follow the trace. Does it connect to one of the pins on the amp pac?
Dan
patriot, blakat and everyone else... i have the panasonic sa-h82 as well. i got it for free and was told that one side of speaker cuts in and out and it will turn off and on by itself. although i have yet to test my new beauty, i DO NOT have a power cord for it and was wondering if you needed a specific cord for it and if you do..where i might be able to find one. thanks Kevin
The power cord is a standard "panasonic type" cord. If you look at the end, it is shaped like a D with an indentation between the two holes. This type of cord should be easily found for about $3-$4. If you can't find one, drop me an Email with your addy and you can get one from me.
Dan
Just got back from checking on this unit. This one uses an SVI3206 amp pac. This is a standard one used a lot, but it is specific to Panasonic and is not cheap ($65). If the speakers are cutting in and out, please check for bad connections around this pac. Fix before it gets any worse!! If the wrong connection is severed, the pac will be junk. Dan
I have a Panasonic SC-PM19 CD stereo system which I've barely used. Today I pressed the remote to turn the system on. Then I pressed "1" on the remote pad thinking that was the way to access the CD in the first tray. Big oops! Since that time, the sterio seems to be basically dead! When it's plugged in, there's not even a red light on for "AC in." I left it unplugged for several hours, then plugged it in again. The "AC in" light came on briefly, then the system turned itself off. Do you think this is the same problem -- the power amp module -- as described above? Or is it something I did with my finger twitching on the remote? I'm concerned that the fee for getting this fixed at a shop would be almost as much as buying a new system!