ex250
Senior Member
Last Activity: 01-23-2025, 08:57 AM
Joined: 06-19-2019
Location: Pontevedra
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please, some input! -
I have not found the problem yet, I checked all the components of a board, I found Q212 with some high measurements in one of the outputs compared to another one that has the same board. I will replace it.
A question that maybe if you can help, the mosfet is necessary to match them? one of them gives a reading vt:3,26v while the other 3 oscillate between 2,91 and 2,99v (2,91v, 2,94v 2,99v)
I find that by adjusting the off set of the speaker as close to 0v (-0.024v) as the potentiometer does not give, the distortion is very high at minimum volume, however, if I leave the...Leave a comment:
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Also, could anyone point how the hell that 10,2 v are generated? and on the TR106 should be -5,1v and I have +5,4v on each side.Leave a comment:
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Well, there must be some other problem, I thought that the amplifier line pre out output of myAV receiver was not giving enough signal for the amplifier on the SW line sockets, however I connected one of the outputs for a speaker through the subwoofer, and even with a low volume the sound is distorted, so there is something else, I guess in the line in / speaker input card.
It probably has to do with pin 6 of CN30 not reaching the 10.2v indicated in the schematic, any idea where to look for it?...Leave a comment:
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Happy new year!
Thanks to point that, now the sub is working, in such a low power mode (vol knob on the middle to high side to hear some sound from), I still think, (without much confidence) that could be for the 8ohm impedance of the speaker used instead a 4ohm one, in IC304 there is -21.64v in and -12.1v out, seems OK there, just reading on the outer pin, and IN is on the middle... I'm feel stupid...
On CN7 the readings are 28,71v and 29,40v
On CN5 pin 1-2=5v pin 3-4=75v
On IC 301 there is still 5v on pin 5.
I just found one cold...Leave a comment:
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On the CN30, the pin 6 should have 10,2v, and reads alternative low values between 0v and around 2v keeping oscillating, with no static value, would check for C135, feel free to give me ideas please, I would appreciate itLeave a comment:
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Sorry I mean before the IC304, out pin 12,4v, in the IN pin should be -21v, but there is 0v. The cap was fine, just changed with another just to try, but same issue. Today the sub not worked to check any differences on the voltages.
Also checked all the voltages on the IC301, all seems on range, except the pin 5, with 4,92v and there appears that should be 0, I don't know if its a typo on the schemeLeave a comment:
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Cap c317 seems fine 11,7uf, I just realized that the line goes to the speakers and line in connection board...Leave a comment:
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I am checking the power board voltages, on CN5 pin 1 there should be -12.4v, and there is 0v. The linked IC303 is -12,4v on the out pin, suspect about the cap C317. The B+ voltage is 5.02v,
[URL=filedata/fetch?id=3538044&d=1735565098][ATTACH=JSON]{"alt":"Click image for larger version Name:\t1735564967756.jpg Views:\t0 Size:\t4.69 MB ID:\t3538044","data-align":"none","data-attachmentid":"3538044","data-size":"medium"}[/ATTACH][/URL]...Leave a comment:
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Kenwood SW-505D no sound issue and pops from time to time when it works
Hello mates,
I bought this subwoofer a few days ago used and blind and it works erratically, as far as I could see, it has been tampered with, the speaker is not the original one and of 8 Ohm when it should be of 4, and there are some welds like reworked by the boards.
It doesn't have much power (expected more from it) and it distorts if you increase the volume over the middle, maybe it's because of the high impedance of the speaker. The problem is that it has sound when it wants, the led panels all work correctly, you can hear the power relay on power on, but right now... -
Re: JVC XL-EX70 no power on stanby
Tried to move both motors with a 1.5v feed and they move slowly, but moves.
I can't guess where is the fault, why the screen flickers with the circuit of the cd disconnected, and there should be some short or high drain because when I connect it screen goes out....Leave a comment:
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Re: JVC XL-EX70 no power on stanby
Soldered one 1000uf cap and same voltages, unsoldered many of the smaller ones and all are in spec....Leave a comment:
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Re: JVC XL-EX70 no power on stanby
Will check the caps, I have no scope.
The C101 states 16v 6800uf, reading around 7400uf on the meter, seems healthy, not?
many thanks!Last edited by ex250; 09-14-2023, 11:03 AM.Leave a comment:
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Re: JVC XL-EX70 no power on stanby
Just checked the feed to the screen and controls, there are some discrepances from my view
on the CN820, from power supply, the pin 7 is 16v not 10v as the scheme, a typo?
on the CN 821 F1 and F2 lines are -29,97v, where should be -25,7v
pins 3 and 4 are 0v and 0,01v and pin 5 is 8.33v
On the feed to the controls, there are 14pin CN802
these are unconnected and with control connected, note the cd player circuit is disconnected and the screen blinks quickly
1 - 0v // 0
2- 4,89v...Last edited by ex250; 09-14-2023, 05:05 AM.Leave a comment:
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Re: JVC XL-EX70 no power on stanby
The voltages from the power supply seems ok, but I don't know why with the cd drive disconnected the frontal screen blinks with some text, a short on the drive? there are 2 voltages on the cd drive circuit 8v and 5v, it's safe to inject some voltage to see if there is anything hot?Leave a comment:
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JVC XL-EX70 no power on stanby
Hello guys, I purchased this week this CD changer to add to my old Pioneer Hifi, well, just lasted 1 CD playing, tried to open the tray to change it and add a full set of three, but got stuck, no opening tray and no response from any button, power but was not responsive and finally unplugged it. Plugged again and no standby led and nothing works.
Opened the case and there is almost one zenner diode that gets quite hot, enough to evaporate quickly the alcohol.
If I remove from the power supply the CD system, the display blinks, also the temperature of the zenner decreases.... -
Re: SDJ01RM vacuum robot not powers on, all dead
nothing happens, LDO regulator and main IC heats considerably both evaporating alcohol after few seconds, now the power button led is not powering on more. I resign myself.Leave a comment:
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Re: SDJ01RM vacuum robot not powers on, all dead
Will try to plug all without the gyro, and see what happens, the heating on the ARM was not burning, only a moderately warm temp, if that is shorted too, nothing to do for me then and should find a new board. On that case, what a piece of shit from Xiaomi/Roidmi for such expensive vacuum robot.Leave a comment:
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Re: SDJ01RM vacuum robot not powers on, all dead
Many thanks mate!, will source one replacement and give reportLeave a comment:
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Re: SDJ01RM vacuum robot not powers on, all dead
Well found at I2608D between Pin 16 VDD 3,3v and pin 13 GND are 1,8 ohms (tester threats that like a short), on board same pins 5,3 Ohms, should I consider damaged the I2608D?...Last edited by ex250; 02-13-2023, 02:31 AM.Leave a comment:
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