Re: Troubleshooting DAV-HDX265 no power
Hi! Finally got some more time to look at this.
>> Check the voltage across the speaker terminals on all outputs.
Hmm, no DC voltage on any of the speaker outputs.
>> you need to have 3.1v on the SD line, 0v means error
Thanks, that makes sense now. I was thinking 3v would indicate the error condition there.
To see what would happen, with the resistors after each amp chip pin 4 removed, I put E+4V into this SD line and the "PROTECTOR PUSH POWER" (SD DETECT)...
rockola1454
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Last Activity: 01-31-2024, 07:30 AM
Joined: 10-16-2014
Location: Fairfax, VA
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Re: Troubleshooting DAV-HDX265 no power
Hi! Finally had some more time this weekend to poke around...
The collector on Q3552 gives about 3.3 vdc when I first plug the unit in, but drops to 0. I notice pressing the Power button no longer makes this unit come to life, it just stays in demo mode regardless what buttons are pressed. Not sure what changed.
I found another unit of the same model at a thrift store, shockingly also would not turn on... I picked it up anyway so I can have some parts to compare & swap.
Unit #2 the power supply...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Oh yeah, I tried that tonight actually... I think it was power on then press stop-eject-power buttons simultaneously, but it ignores the combination, similar to trying to change FM frequency displayed. I'll take a closer look at page 24 and post any developments, thanks!!Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Thanks RJ!
>> Locate Q503 & check the voltage on the collector, it should be 3.3 volts.
Yup, I see 3.2vdc.
>> Short the collector to the emitter for a second and see if it resets the micro. This will do a manual reset on the micro.
Yup! Display went off, then a few seconds came back on.
Unfortuntately, no change in behavior though :-P Pressing Function button or Eject cause the unit to flash "Standby" and power off.
>>...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Progress!
So, there were so many tiny components near IC503, that rather than lift pin 1 I just lifted the entire chip using my hot air station. Shorting pad 1 to GND does nothing, but shorting it to VDD makes the display come on! The demo mode starts doing its thing.
>> check the resistance of ic503 pin1 to ground just to make sure C521 is'nt shorted
I measured about 10K, so likely the IC is defective.
It looks like there's some more damage, but not sure how...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Hi RJ, Thanks for the info! Sorry for the delay, things have been busy lately.
>> when you push the power button, ic501 should see that command and outout 3.2v on P_CONT1 to turn on the rest of the power supply
P_CONT1 stays at zero when pushing and releasing the power button.
>> You won't have a display untill you have D+5V, and to get that voltage IC942 needs to be enabled by P.CONT3
Indeed D+5V is not present (0.3vdc), and P.CONT3 stays zero as well.
...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Thanks! I resoldered the pins on both transformers, but didn't notice any cracked joints.
>> that 6V should only be 6v, if it is higher, it could be due to a bad C944, when they get weak they don't
>> filter properly and can show a higher than normal voltage
I checked C944 and it tests fine, but replaced it anyway. Now measure 8.0vdc for CN906 "6V", but it slowly creeps up.
>> You can check the other voltages from this section of the power supply at there supply...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
>> before you reconnect the power supply is to check the resistance between the pins 1 and 4 on CN3002
No short detected.
>> It looks like the power supply is working, I would connect it back in. and see if it will turn on.
Screwed in & plugged power board back in, leaving CN3002 disconnected, but still nothing on the display.
>> Pin 11 & 8 are low because you need P.CONT1 to turn on ic941 & 943. When CN906 is connected to
>> the main...Leave a comment:
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Re: Troubleshooting DAV-HDX265 no power
Thanks, RJ!
> What voltage are you measuring on CN906? Just use chassis ground. Or if you are working on just the power supply out of the unit,
> use pin 7,10 or 12. The voltage you need is 6Volts, (pin6), this will be the standby voltage
Ah OK, I'm just working outside the unit, so using pin 7:
1) P.CONT1: 0.0
2) P.CONT2: 6.5
3) P.CONT3: 0.0
4) E+4V: 4.0
5) D+3.3V: 0.0 * initially measured some voltage but gradually droppped to 0.0
6) 6V: 8.3
8) D+5V:...Leave a comment:
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Troubleshooting DAV-HDX265 no power
Hi! I have a Sony home theater system that won't power up, model DAV-HDX265.
It contains a power supply board 07dav-power-13-mp (1-872-105-13). I've checked a few things, but not sure where to go from here. Attached some pics, if any zoomed-in shots would help just let me know.
- the voltage from CN904 marked 31.5vdc measures 0v
- the voltages from CN906 don't make a lot of sense to me, but I'm not sure if I should be measuring from chassis gnd or "D-GND" on CN907...
- I checked all electrolytic caps with an ESR meter, and nothing looks suspect;... -
Re: Vizio M550SV backlight but no picture
That was it! My R25 went bad; it looked fine but resistance check kept getting between 1.5 and 2K Ohm. I used your spreadsheet to determine a 180 Ohm resistor should be there, installed one and the voltage is back down to 3.3vdc again.
Thank you so much for all the help!
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Re: Vizio M550SV backlight but no picture
Thanks, budm! So this story gets even more weird...
Tonight, I figured the last thing I did before the backlight quit was removing and resoldering the fuses, so I decided to try pulling them back up for the hell of it. I didn't notice any issues visually except that a couple pads are missing, so to solder the fuses back I scraped some green enamel away from traces that connected to where the pads used to be and soldered to that. Plugged it in and F2 now has 12 volts, and amazingly I'm getting the "V" logo and can...Leave a comment:
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Re: Vizio M550SV backlight but no picture
@RDC55 Good point... I went ahead and resoldered the fuses and touched up the regulators just to eliminate sloppy solder as an issue.
@budm
> We also need pictures of the whole back side of the TV showing all the board.
Done!
> Do you get 12VDC at both ends of the SMD fuse with ref. to the chassis GND on the T-CON board?
I think they combined the T-CON and main boards into one in this unit... I removed the floor stand bracket and underneath I don't see a board, just ribbon cables...Leave a comment:
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Vizio M550SV backlight but no picture
Hi! I obtained a Vizio M550SV TV and am attempting to repair it. It powers on and the backlight comes on, but there is no picture. If I hit the menu button I can see different sections of the backlight get dimmer/brighter, so as far as I can tell, the TV thinks it is alive.
Upon pulling the main board, I noticed the previous owner attempted some repairs of his own. Two voltage regulators AMS1117 have been replaced, the two white fuses, and a few capacitors.
I noticed some sloppy soldering on the replaced parts, but probing around with my Fluke meter I am confident... -
Re: Mitsubishi LT-55154 Blinking Green Light?
Update: my LT-55164 lives! I studied some videos on how to reflow chips, and picked up some liquid flux and a X-tronic reflow solder station. Performed the operation on just the Broadcom video chip, using some Sekisui thermal tape to re-affix the heatsink. Turned it on (thinking in the back of my head, no way this will work), and voila! Been using it for a couple weeks now, and haven't noticed any issues.
I also attached a small fan on account of how unbelievably hot the heatsink gets after only a few minutes of on-time....Leave a comment:
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Re: Mitsubishi LT-55154 Blinking Green Light?
Michael, you (and Nyjetfan21) are a genius for figuring this out!
I believe I have the same exact issue, my green blink symptom is the same and all suspicious caps have been replaced with good ones. Did you need to remove the chips before performing the reflow, or just heat them up as they were?
I have never attempted to perform a reflow on a GPU/BGA chip before, but if you happen to know of any links or tutorials that could help me perform the same operation you did (what equipment I need, the general process, temperatures,...Leave a comment:
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Re: Mitsubishi LT-55154 Blinking Green Light?
I have a LT-55164 I've been attempting to repair now for many months. Same issue, never ending green blink of death.
Per the service manual, the power supply is supplying correct voltages to both main and inverter boards. Since the voltages are correct, I reason that my power supply board must be good. It does not use crap brand electrolytics, and all caps test good.
Per the service manual, if the LED inverter board detects a short, a multi-color LED blink sequence will occur. This is not happening, and...Leave a comment:
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Re: Learning SMD capacitor markings
I never did make any sense out of the codes under the values. The best I could figure, you have to dig out a schematic to find out what they are ...
Sure would be useful IMO if they just printed the value & voltage.
Laptop is still running great after the replacements, it definitely did the trick.
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Re: Learning SMD capacitor markings
Hi guys!
I ordered 10 replacement capacitors on ebay for $15 total, and after soldering them in, am happy to report that the laptop has a clean bill of health. One week and no issues! The main issues this solved for me were the display going nuts, and extreme slowness. The slowness was strange... not a HDD caching issue or something like that -- with nothing open but one browser and no hard drive activity, the laptop was barely able to display a web page. It was acting as if the CPU cache had been disabled. Now it's fast as ever again....Leave a comment:
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Re: Learning SMD capacitor markings
Thanks for the help, guys! After some long digging, i was able to find the schematic for the M90 motherboard, a Compal la-2881p. It has the capacitor voltages I was hunting for, too.
Heading out for a weekend getaway, but next week I'll dig into the schematic and see what i can figure out with the charger signal wire....Leave a comment:
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