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Question about Fisher RS909

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Mystery Voltage Unit trips into protect mode for no aparent reason. Just as msyteriously as it trips in if you shut it off and turn it back on sometime it will work sometimes it will not. Checked for bad solder joints and loose ground, shorted output or output out of range and all seem to checkout just fine. The only real clue I have found is when you meter the voltage at the filter caps and discontinue the voltage one cap will drain completely to zero volts at the proper RC curve. But the other will only drain down to a seven volt load and stay there. But it follows the proper RC curve it just holds the last seven volts. Replaced Both Capacitors, checked the Bridge Rectifier. Seen this in other electronics and could not identify why this is happening. any advice no matter how technical. Will be appreciated

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Well now you did most of what would be recomended. Try this, When the unit trips into protect, check on the output pin on the output IC or if its a transistor output the speaker output BEFORE the protect relay.. If theres any DC voltage on the output pin then you know the problems in that IC or output circuit. If its a transistor type output, I would suspect the differenal circuit. Way up near the input circuit. Its two transistors back to back. They may check good on a regular check so do a high resistive check And see if theres any type of leakage. These I have seen many many times in a Sanyo/Fisher Stereo system to be the problem. If its an IC output, try disconecting that side of the bad output and see if the unit works ok. If theres no DC voltage on the speaker output pins BEFORE the saftey relay then I would suspect the protection circuits bad. Theres op amps in these circuits that are used as comparators and they do go bad. You dont want to dig this deep and get a service diagram, and the units over several years old TOSS it and upgrade!! Good Luck

Posted on Aug 05, 2006


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I have an TX-SR313 for a year now and it was working perfectly until yesterday it just automatically shots off even when I turn it on for several time it just shots off. How can I solve that Problem?

Hello, It seems like the receiver is going into protection mode. A unit will only go into protection mode for two reasons mainly. The first reason is if there is an internal short. The second is if there is an external short which is typically only caused by one or more of the speaker connections. To isolate whether the short is internal or external, you would first need to unplug the receiver and disconnect all of the speakers. At this point you will plug the receiver back in with no speakers connected and turn the unit back on. Also turn the volume up to about 70 (even with no speakers connected). If the unit stays on that means that one or more of the speaker connections was causing the receiver to go into protection mode. If the receiver shuts off again with no speakers connected, then that means the unit would have an internal short and would have to go in for service. Thanks, FJD

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What brand/model receiver? Some will lock themselves into protect mode if the protect circuitry is tripped too many times.

Turns off after two seconds when turned on any suggestions please?


It could be a problem of cold solder joints, or solder joints on the main board which have cracked over time due to thermal expansion and contraction of the circuit board. Repair is to find and reflow the cracked joints. You may want to consider hiring the services of a reputable repair professional to deal with getting your set back into normal operating condition.

However TV's attempt to protect themselves from damage by shutting down. Your unit has three main ways to protect from damage.


The TV monitors various DC voltage supplies. If one of the supplies is missing. The TV shuts off.


The TV monitors excessive high voltage and beam current. When the TV detects that one of these is too high the TV shuts off.


This will activate if excessive current drain on the 130 volt supply line. If the TV detects this supply line is too high the TV shuts off.

Most units made in 1999 have a diagnostic mode to help determine the cause.

Thanks for contacting

Please do get back to us for further query.


My kenwood krf-v5300d overloaded? Stand by light flashes if pressed stops flashing if pressed again unit turns on but doesent pass start up and shuts off again havent managed to find a solution from bassic...

This unit is in what is called "protect" mode/ See the link below for an explanation of this. Specifically to your unit, the output components are unique to Kenwood and are not cheap. Further investigation to locate the reason for the protect mode will be necessary prior to any attempt to estimate the cost of repair. Something as simple as a missign voltage can cause this symptom.

Please feel free to update this with any other questions or concerns that you may have.



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Is the protect light in your amplifier turns on when it shuts down? If yes, then your amplifier lacks voltage. The reason why it goes on protect mode is, the amplifier is needing an amount of voltage from your car, since your car cannot provide that amount of voltage your amplifier is not getting anything, instead of getting voltage to produce watts its getting minimum voltage & producing heat, to save itself it goes on protect mode so the incoming power shuts off & cools the amplifier.
Your on vol 40, amplifier is working fine, when you turn it up to vol 50 your amplifier shuts of, then you put it back to vol 40 & your amplifier turns back on.
At vol 40 your voltage is 12v or above. but in vol 50 your voltage drops to 11 & below.

Check your battery or alternator if they are giving enough voltage

Hope this helps your inquiry. Have a blessed weekend.


My jvc hx-d7 radio is turned on in 2 seconds it shuts down to protect mode how do i take protect off ?

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The unit is detecting a problem and shutting down in what is usually called "protect" mode. Look for bad connections on the board near the voltage regulators.


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it's not actually a problem my friend. it could be a problem with the output circuitry and your protection mode is activated. there ar ecases that systems shuts off with no appraent reason and those are isolated cases. If that were so on your units, the problem lies in the systems board (CPU) a defect in the backup power supply. also grounding problem of capacitor leaks. if there is no trouble in the power amp section and works well suddenly trips, some modifications can be done. i dont know if that can be solved by your technical experts on how to modify the protection circuit. the principle on protection circuits of yamaha is just one and same. but newer models has got better but sensitive designs. 2095 is about 3years younger than a1000. 2095 is almost all digital when a1000 uses mechanical switches.

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