My sa-he70 has the f70 fualt have checked fuse no. 1,3,4,5 can't find fuse no 2. have checked for the 12v dc at fan receiptical no voltage, have put 12v dc onto fan,runs ok.

SOURCE: TECHNICS SA-DX850 F70

It could be an overload from two speaker wires crossing, check the owners manual for error codes.

Electro Med Services

• 6694 Answers
• Posted on Sep 19, 2011

SOURCE: I have a panasonic SA-HE70 amplifier and all it

hi,.

First of all remove all the speaker connections from the amplifier. After that power the amplifier and check that it gose Over load ( protection ) show or not . if not, then any of the speakers or its wiring have some problem. If so the reconnect the speakers one by one and switch ON the amplifer and check.find out on wchi speaker it shows lover load.

if the amplifer shows overload even after removing the speakers then you have to check the amplifiers hardware.

Also added the procedure how to check the amplifier satge. You should have a good knowledge in electronics to do the following. Also need testing instuments.


AV receivers shows protect mode , when there is a hardware fault in side it. Its a warning that some thing is wrong.
Normally AV receivers show this when any of the output amplifier have some problem. there are five amplifiers in this AV receiver. This problem occur when the output diver transistors of any of the amplifier become shorted. if the output transistor get shorted this will lead to flow of current through the speakers. To prevent this there is a protection circuit for each channels. One combined output of this protection circuit is connected to the system control. when the any of the output amplifier fails, the protection circuit detects it and switch of the speaker and sent data to the system control. when the system control get this data it will give a warning to the customer through display that PROTECT.
You have to check the amplifier.

For that you need digital multimeter,soledring iron screwdrivers etc

Open the amplifier , then power it on. connect the negative terminal of the multimeter any where in the chase( metal body of the amplifer). then connect the positive terminal to all the output transistors emitter pin one by one . the voltage should be bellow 0.5V. If any of the emitter of the transistor shows voltage more than 0.5V., then that amplifier stage is faulty. Remove the transistors and check it. if it is shot then replace with a new one.
after replacing the transistors do not power up the amplifier directly from the main. You have to put a bulb of 60 watts in serial.
You can do this easily remove the mains fuse. put the bulb in a holder. now you have to wire from the holder. connect one of it to the one end of the fuse holder and the other wire to the other end of the fuse holder. Why using a bulb is, if there is any further problem in the amplifier stage on which the transistors replaced, there is a possibility of the new transistor get damage. if we use a bulb in serial with its mains supply ,when any overload in the amplifier occur the bulb will drop the current, by lighting itself.
After connecting the bulb in serious power on the amplifier. watch the bulb. It should light for one or two second and go dim . if so check the display, is there is protect mode is on or not . if not and come back to normal operation ,then remove the power , remove the bulb insert fuse and check
connect the power and check.
If the bulb shows bright light then there is some component also faulty in the same amplifier. after removing the power you have to check again the amplifier stage of which the transistor is replaced, for any other faulty components
OK