Re: Philips FR-740 working but no audio output
page 16,
make sure all 6 volume settings are centered.
page74 shows the audio leaving the input selector into the amp circuits through an electrolytic.(2541,2542)
i would scope or tap off of that to see if the audio is making it through the switching section first.
this is a complex bastard, but atleast the schem's are readable!
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Re: Philips FR-740 working but no audio output
sure, here is the link:
but can't figure it out what is the problem. Voltages seems to be all present. Maybe the final amplifier are brokenLeave a comment:
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Re: Philips FR-740 working but no audio output
any schematics around?
philips used to sell the service manuals so someone must have scanned one!Leave a comment:
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Re: Philips FR-740 working but no audio output
Yes i tried all the output speaker (2 front, 2 rear, 1 center).
+40V and -40V is present in both STK, solder connection looks perfect.
These voltages are printed in the philips schematic:
STK496-070 (i have STK496-090 in the pcb):
9 = 39,5V
3 = 40V
8 = -39.5V
12 = -33.6V
1,2 = -40V
4,5,6,7,10,11,13,14 = 0V
STK496-270
11 = 39,5V
14 = -33,5V
10 = -39,5V
3,4,19 = -40V
7,8,9,12,13,15,16,17,18,20 = 0V
Measured those values, all verified. But -33.5V and +-39.5V is a little bit higher, cause voltages are 40.2V.Leave a comment:
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Re: Philips FR-740 working but no audio output
Looks like if it has audio to the headphones, there should be audio getting to the input of the stk ic's. Did you try all the outputs? meaning the sorround speakers as well.
I guess check and make sure you have + & - 40 volts to the ic's, then I would check the solder connections on the ic's sometimes they break
Since its not in protect I would think there is 0 volts at the + of all the speaker terminals, maybe check and make sure.Last edited by R_J; 09-04-2017, 09:15 PM.Leave a comment:
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Re: Philips FR-740 working but no audio output
No, it powers on normally, no errors.
No items or other stuff inside the headphones jack.
Inserting IN and OUT the headphones is correctly detected.
For example with headphones connected, i cannot enable the surround mode, because it says (take out headphones first).
If i disconnect headphones, then i can enable surround mode.
Headphones are working good, very good and clean sound.Leave a comment:
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Re: Philips FR-740 working but no audio output
plug in some headphones to see if there is sound from the headphone jackLeave a comment:
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Re: Philips FR-740 working but no audio output
Does it power on normally, or is it some error like protect? If it powers up with no error, maybe something is stuck in the head phones jack?Leave a comment:
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Philips FR-740 working but no audio output
Hi everyone,
i got this Philips FR-740...it powers on, i can see the front display, but no audio output at all.
No burning components on the motherboard. Any suggestions?
Here there is the service manual
thanks
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Good morning everyone,
I'm trying to repair an onkyo ht-r390 that has no sound output, despite the volume being at maximum, the rest seems to work; the video output signal (coming from an hdmi input) is present, but the audio is absent. Similar situation if I send an audio signal from any input I have no output.
The firmware reported is the following:
M:1.00/11107BLP
D:?.??/????????
O:1.00/11107AL
The DSP firmware given the question marks seems corrupt.
On the BCHDM-0678 - 25140678 - QPWBCHDM0678A0 board the chip that usually seems...05-11-2025, 02:59 AM -
OAUD Yamaha HS8S Audio one output only.
I have pulled the output board. Output txsistors are ok (only 2 main output). Everything measures the same on each side. Customer did not bring in speakers so I cannot go too deep. I did notice a greenish tint on the tip of the solder joints that connect to the COPPER output connectors. All 6 have a greenish tint at the tip - each side has 3 pins each. Anyone else have copper speaker output pins that corrode at the place on the PCB where they are soldered? I will try to add a photo. Thanks. -
I have here a Magnum IA.100 which belongs to my parents.
The unit powers on & when the relay kicks in, you get a pop from the speakers (this might sound weird but is usual behavior for this amp). However, you get nothing coming through it from any of the inputs & no pops and crackls from any of the controls.
Because of the sound from the speaker when the amp turns on I have assumed that the output section probably works but I could be wrong & I'm not sure how to test that side of things further.
What Ive done........01-01-2025, 01:26 PM -
Hi guys, I have this AVR-X500. It has no audio output but if I select some input (DVD) and connect an audio signal to the RCA DVD inputs, I hear a relay click and sometimes there is a slight crackling on the speakers.
I only have 2x 8ohm speakers attached to Left and Right front.
If I plug headphones in, the crackling noise stops but I get no audio on the headphones.
I checked the voltages marked on the connectors on the Preamp PCB (12V, 5V etc) and they are all present. There is also plus/minus 56V on the bridge rectifier on the main amplifier PCB... -
Hello Guys,
Greetings!
Hope you all are doing well.
I am looking for suggestion on Yamaha 2064. The problem with this receiver is that it has no sound however when the test tones are activated it does outputs from all the speakers. It is working in two channel stereo mode but when you select other sound modes, it doesn't. The last time it had a problem, I had replaced the DAC
PCM1681DBQR - IC263 and it worked fine.
Other issue with it is one of the STK ICs is getting more heated then the other one but that can be looked at later.
...
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