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  1. dorke

    Amp keeps going into protection mode

    The last R3 measurements : "R3 reads on both sides 0.01 at minimum volume and reads 0.04 on one side and 0.07 on the other side before protect mode." do not agree with the R3 measurements on post # 32: "R3 reads .001 at minimum volume, and goes up to as high as 1.30 before going into protection...
  2. dorke

    Amp keeps going into protection mode

    O.K A few more tests on the switch /indicator board. Same as before, at minimum volume and than at a bit before the protect trip. DMM to DCV20 . Black probe at one of the black speaker connectors(any would do fine). Test the voltages on each side of R2 and R3 and R8 (a total of 6 points and 12...
  3. dorke

    Wiring a Fire Bell to a flip switch?

    Wow, You have connected AC (from the transformer) to the bell,not DC as required. The transformer is probably of the type output 12VAC-0-12VAC,input =120VAC. Please identify(with a photo of writing) the input and output? Is there a 20 to 24VDC power supply available for testing that the bell...
  4. dorke

    Amp keeps going into protection mode

    o.k The last set of test looks like the fault condition isn't due to over-current in the power Trs. Another set of tests on the main board: Same as before, at minimum volume and than at a bit before the protect trip. DMM to DCV200 . Black probe at one of the black speaker connectors(any would...
  5. dorke

    led display (on behalf of Davedpg)

    Is this home work?
  6. dorke

    Amp keeps going into protection mode

    o.K that is some progress. While driving a single channel input only (note which one you drive). Let's measure some main board voltages on R7 , R73 , R121 , R169 , R217 all are 47K resistors,near the big blue caps. Same as before, at minimum volume and than at a bit before the protect trip. Be...
  7. dorke

    Amp keeps going into protection mode

    Let's do a voltage test on the power switch/indicator board. Use the DMM in DCV 2V range, to measure the DC voltages on R2=10k,R3=100K,C9=104pF Measure the voltages with volume at minimum,what do you read? Slowly crank the voltage up till the protect trips. What voltages do you measure just a...
  8. dorke

    Amp keeps going into protection mode

    The HK3470 is a stereo receiver,you can only drive 2 channels at a time with it. I assume you are using the "pre-out" for that. If the volume level is below that causing the protect-trip, Does the amp play clear sound? What is the impedance of the speakers you are using?
  9. dorke

    Amp keeps going into protection mode

    Rick , don't run buying anything yet. There are things we can check before you do. What are you driving the 2.1 amp with? Try this: physically disconnect all inputs to the amp. Power the amp up and notice the LEDs behavior. Do you get any flashing green? for how long? when does the blue come...
  10. dorke

    Amp keeps going into protection mode

    You are correct, it is should be R9(not R99) and R100, they are the same value resistors 6.8K.
  11. dorke

    Wiring a Fire Bell to a flip switch?

    Welcome to EP. The bell reads:"20-24VDC /0.085A " If you connected it to mains no wonder the fuse blew. After that kind of abuse ,lets hope that this bell is still working.:( Do you have a DMM ? Do you have a 20 to 24V VDC power supply(a wall-wart will do)? Please show the connection...
  12. dorke

    Looking for the name of this connector

    Welcome to EP. Finding this connector can be a headache . There are so many variations from so many vendors. What makes this one a headache is the triangular keying it has. Do you have a parts list? Can you connect the manufacture for info? If the answer to the above is No. The best would be...
  13. dorke

    Amp keeps going into protection mode

    Yes , (+) red on one and(-)black on the other. The meter on VDC 200. An example for one channel(you should do it for all).
  14. dorke

    Amp keeps going into protection mode

    Is the ±55v present on each channel? What do you read ?
  15. dorke

    Determining if load is lagging or leading based on powers

    Yes it is . A lagging (inductive) load absorbs power. A leading (capcitive) load injects power. Yes the square root of three , for Voltage in a 3 phase Y connection,when the voltage of the branch is needed. note: the same applies to the Current in the DELTA case (par.e) Look at the "power...
  16. dorke

    Amp keeps going into protection mode

    You have 5 channels each with it's own PA like below: Check that each stage has the ±55VDC across the big blue filtering caps. It may be easier to check(carefully!) the voltages on the grey 6.8K /2W resistors next to the caps. If all voltages are present(a total of 10). Do this: Disconnect the...
  17. dorke

    Is this circuit possible?

    "quite unreliable", mate(Ozzie talk), that's an understatement.;)
  18. dorke

    Is this circuit possible?

    Bob, Is this some kind of Adams family sarcasm? Must be since, it's already past April 1.
  19. dorke

    Dumb USB Charger - Just 5v DC & 200 ohm resistor on +?

    Welcome to EP Daniel. What USB standard are you talking about? There are a few already, and they are evolving and changing in many ways. What are you going to use the USB for? Look here for details
  20. dorke

    Amp keeps going into protection mode

    Yes DC 200mV range. Is this what you get on all channels?
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