When i turn my sa-ht40 on it says power overload

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I have the same problem with my Panasonic model SAHT-40. I get the same code plus popping and shortly reads maximum overload then cuts off. I disassembled my unit and discovered that my fan fails 2 work causing the unit it over heat. I called Panasonic 2 place an order 4 a cooling fan. This model is obsolete they dont even manufacture parts 4 this unit anymore. The closest that I can get with my credit card is Samsung model AH31-00056B cooling fan through Panasonic. I hope that this solution helps all of u out with ur unit!

Check the speakers and the power supply for any signs of shorting.
This is due to the fact that the safety circuit works to switch off the set preventing a high damage.
So check the output for short or the presection .

The question is what is causing the overload? The power supply or the output devices on the heat sink?
If you have accidently shorted a speaker wire, then the answer will be output devices, otherwise it could be anything in the power section. You may find a burnt or damged device with either of the causes.

An amplifier should never be turn on without speakers, it will overload internally.
make sure speakers work and try again.

try this mate:
http://www.electronicspoint.com/googlesearch.php?cx=002919058480771089906%3A03mranmmdze&cof=FORID%3A10&ie=UTF-8&q=Technics+SA-GX550&sa=Search#862

First of, be sure volume is turned all the way down before or as you are powering it it.
Second if that does not work disconnect all speaker, and input/outputs.  Power the device on and see if it says overload.
If it does skip the rest of these steps, your capacitors are bad or the power supply is no longer functioning correctly.
If it doesnt, start with testing each speaker at power up.  Match the speaker to the output it goes on, power the device see if it says it. 
If it does on any speaker test it is a speaker issue or a terminal issue.  To test for terminal or speaker issue plug a different/ known to work speaker in that same terminal, if it doesnt say overload it is a speaker issue, if it does say overload it is a terminal issue.
Once you have made sure all speakers and terminals work correctly start plugging input and outputs in and test individually.

u can measure the speakers impedance, if is ok. I think this can be a problem, when is speakers with 4ohm conected.

you mite be pushing too much power, try unhooking a few speakers or check the wattage cuz that mite be your problem