Panasonic surround sound system

[kentucky]

Hi, I got a panasonic sa-ht520. It started given a F61 alarm at startup and then dies. There is a big ic [processor ] on the pc board that control the whole system. On startup it checks the system. Either this chip went or one of the inputs to the chip is bad. It got 100 pins. It does get 5vdc. The speaker wires are fine, no short or a voltage on them. I did remove the power amp ic, but F61 stays there.

I phone the local Panasonic repair and spoke to there technician, which told me this set is about 12 years old, no spares for it, and he is not allowed to give me any repair manual. I did find wiring diagrams for it, but somewhere in the startup, it checks certain things, of witch one is bad. I will be happy if someone can help me.
thank you.

[Khron]

Re: Panasonic surround sound system

This might be a bit more appropriate in the Audio section:

https://www.badcaps.net/forum/forumdisplay.php?f=34

Also, i guess you just didn't dig (deep) enough:
http://elektrotanya.com/?q=en/showre...oria=&kat2=all

Service manual page 22 says as follows (re: error F61):
"Cause, Troubleshooting"
Power circuit system failure and/or direct current flown to speaker terminal
Identify the cause and replace with new parts"

Ignoring the "engrish" that made that "flown" appear there, assuming you have a multimeter, a good first step would be to connect it to the speaker terminals (each output, in turn), power the device on and check if any DC shows up on the output.

You might also find this useful, since all the power amp circuitry seems to be inside the subwoofer:

[kentucky]

Re: Panasonic surround sound system

Thank you Khron for replying
Power circuit system failure and/or direct current flown to speaker terminal [this was tested and is ok]
Identify the cause and replace with new parts [As said , there is this 100 pin chip on the pc board that controls the unit] either it went, or one of the input that tell it something is down is down. I was hoping for a write up on how that chip operates.

[Khron]

Re: Panasonic surround sound system

If the processor itself had crapped out, there would've been nothing left to drive the display to tell you the error code

I'm pretty sure the processor is just some relatively generic microcontroller; "the way" it operates depends 99.8% on what's in the programming, and good luck finding anyone who can (or is willing / allowed to) tell you that.

If there's no DC on any of the outputs (i assume you tested all the outputs, each one per one power-up attempt?), then it's time to start digging through the signals on that "umbilical cord" between the main unit and the subwoofer.

[kentucky]

Re: Panasonic surround sound system

Thank you, Khron
Will go and give it another go,
I have also read somewhere of someone saying his F61 was cause by the dvd drive capstan motor. Mine does not move on power up with this F61.
What I can tell you is that the ac relay comes on for 3-5 seconds, but there is a dc to dc converter that needs to give the pc board power, it keeps stuck in stby mode, also means no output. when I apply output on their, the set says good bye, when pressing the on /off button.

[Khron]

Re: Panasonic surround sound system

I don't see any dc-dc converter in the power section. The stand-by supply seems to be a small transformer, a bridge rectifier and a discrete linear voltage regulator (subwoofer schematics, page 15, top right), which produces a "SYS6V" which goes all the way to the "main unit".

[kentucky]

Re: Panasonic surround sound system

IC2002 , page 71, shematic diagram 15, top.
that big ic is on page 87, pin 68 supply that dc to dc converter. First time I see this sheet. The ic is also on page 70.

[Khron]

Re: Panasonic surround sound system

Oh, right, there is that. I'm pretty sure they drew D2009 upside down by mistake, that's definitely not supposed to be pointing that way.

IC2002 gets supplied from the output of bridge rectifier D2023 (page 71, top right), smoothed by C2080 (page 72, top left). The AC going into that bridge rectifier comes from pins 23 & 25 of the subwoofer cable (signals SUBAC1/2). Inside the subwoofer, that's supplied from the 3rd(?) winding of the power transformer.

They key thing is, there's a polyfuse in series with that (FP1, subwoofer schematics page 14, bottom right). See whether that still has a low-resistance reading. If it measures higher than a couple ohms (or totally open-circuit), that might be the culprit.

Can't really see where the display controller actually gets powered from (SW5V signal - i can only see it on the display-board connector, and on page 72, but that's only a voltage-sensing circuit).

[kentucky]

Re: Panasonic surround sound system

Thank you, will go and play with it.

[kentucky]

Re: Panasonic surround sound system

Hi Khron, my set is fix.
I saw on the pc board where the dvd are, their are 2 yellow spots, hi heat, starting to test and found a capacitor, 100 mic/33volt short. It is C2085.

Thank you very much for your care,

[dick_barton]

Re: Panasonic surround sound system

Usefull information for anyone else with the same problem. Thanks for the update.