Unfortunately, the danger of operation without loads (speakers) is generation of rather high voltages (resonance) that may damage the chip. The chip is not protected against that. The 10 Ohm test indicates if this has happened.
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I ran those tests from the center pin on the dc connecto to all 4 output leads When I set my multimeter to 20k ohms it starts with 1 with the leads separated I take 1 to mean infinite resistance in that context That's what I get for all those tests I also tried with one of the corners around the power connector, same thing
The test is performed both from the center pin (+) and the outer terminal (-) to all 4 output leads. An output may "hang" (permanently shorted to) on + or - or even both (in which case also the power supply terminals show a kind of short-circuit.
What the DMM shows when you measure impedance is rather easy to test. Keep the two measuring wires apart and the display will show the symbol for high impedance (depends on the DMM). Short circuit (let them touch) the two measuring wires and you should see "0.00" in the display.
What the DMM shows when you measure impedance is rather easy to test. Keep the two measuring wires apart and the display will show the symbol for high impedance (depends on the DMM). Short circuit (let them touch) the two measuring wires and you should see "0.00" in the display.
My DMM with probes apart always reads 1 So 1 with probes apart and also 1 for all tests between the positive terminal of the power connector and all 4 speaker outputs (2 + and 2 -)
Good, then it is likely that the power amplifier is fine.
Your board contains three building blocks (Bluetooth receiver - control section - TDA7492P power amplifier) that all have to function well before you have any sound out.
In a previous posting, you described that you seem to have a correct connection to the Bluetooth module.
You have just re-tested the power amplifier section and it also seems to be fine.
Then, the control section needs to be looked at. A posting said that Youtube has many videos showing how the control section is used. Did you study these videos?
I watched all the TDA7492P videos on youtube There's no control section video I tried pushing all buttons Today I borrowed a pair of 8 ohm speakers from someone that came from a super low powered cheap ca. 1970 Emerson Stereo Although the speakers are probably only rated 10 watts, I still don't get any sound
Sorry for not having responded for some days.
As long as you do not play loud, such a class D amplifier will accept any speaker down to 4Ohm and any power supply with at least 1A capacity and a voltage within its supply range.
The very unfortunate situation is that a Bluetooth circuit, we do not know how is designed, and a control circuit we do not know how works, prevent the amplifier from being activated.
The normal way to proceed would be to work our way backwards and first isolate the power amplifier by cutting some PCB tracks and try to make the power amplifier work on its own with direct control of the IC-leads. Such is for this board difficult because it is a small SMD IC housing and the board is densely populated. Unless you are experienced with SMD work, you risk damaging something and the board becomes useless. I hope you did not pay much for this board.
Though such all-on-one boards are practical when they work well, I advice people to buy separate boards such that each element (Bluetooth receiver, evt. MP3 player, pre-amp, power-amp) can be tested and eventually replaced separately.
Before the power amplifier is activated, there is little we can do.
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