IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

[nomoresonys]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Hi,
I have one power supply exactly like that one from your picture.
if you take a look on the schematic diagram (attached), you have the PD connector, on right hand side at the bottom (right corner) of the schematic diagram.
I've checked the stand by voltage, which is 5 Volt, at pin 8 on PD connector.
if you connect the pin 4 (PS_ON) to pin 8, the power supply starts and all the voltages are present and correct.
but, the TV doesn't start.
any thoughts where I should take a look? I assume is something wrong on TV, not on the power supply.
thank you.

With the jumper in place are you getting voltage on pin 5 AC_DET? should be around 3 volts when tv is working correctly.

[i-didnt-start-the-fire]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

I am an ameteur so I will just ask some questions to get our troubleshooting juices flowing while we wait for the experts.

"...the TV doesn't start."
does the set move out of standby with the remote but the screen does not show anything and there is no sound or nothing happens.

"...all the voltages are present and correct."
Does that include the other connecters like the 60v inverters on LA_R and LA_L, and the 12v etc.

[alexrb2020]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

R7914 is the 2.2 OHMS FUSIBLE resistor 1/4W (or 1/2W, you have to measure the dimension) for supplying B+ to run the STBY power supply section, (you can use 2.2 Ohms MOX type which is Flame proof )that will blow open when that SMPS IC for the STBY power supply shorted out. R7918 is still OK?
Sharp RDENCA235WJQZ (DPS-304BP-1) Power Supply Unit
http://www.shopjimmy.com/sharp-rdenc...pply-unit.htm#

Hi,
I have one power supply exactly like that one from your picture.
if you take a look on the schematic diagram (attached), you have the PD connector, on right hand side at the bottom (right corner) of the schematic diagram.
I've checked the stand by voltage, which is 5 Volt, at pin 8 on PD connector.
if you connect the pin 4 (PS_ON) to pin 8, the power supply starts and all the voltages are present and correct.
but, the TV doesn't start.
any thoughts where I should take a look? I assume is something wrong on TV, not on the power supply.
thank you.

[i-didnt-start-the-fire]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

I have found the answer to my question immediately above.
I have a copy of Justine Youngs Troubleshooting and repairing switch mode power supplies which I am reading through.
He explains that there is one or more high Ohm startup resistor between the primary 300VDC caps of and the power IC. If this shorts or opens it will cause No-Power problems and sometimes intermittent power problems.

[i-didnt-start-the-fire]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

My other question is hard to word and may be hard to answer because of this.
I want to know how you worked it out.
There was low resistence on the ENUV PIN. I would have come to the conclution that the resistance through the IC was bad.
You knew there was something else on the board that was lowering the resistance.
I know this is probably electronics basics to some but it was enlightening.

[i-didnt-start-the-fire]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

I pulled 6 little orange and black diodes off another board to solder one in thinking they were all the same
Did I mention I am a novice...
But decided to zoom in with a photo to see if there were any markings and noticed the one I removed was marked with TZX 15B
I checked the others 3v3 6v8 16B

I was going to ask here if I could use the 16B, but decided to just put the 16v in. It worked What the potential issues with this decision?
Do you think I need to change this diode to 15v or one that you mentioned (D7905)
i.e."7.5V should be OK or 12V 1/2W will be more than enough"

[i-didnt-start-the-fire]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Thanks BUDM!!!
This thread helped me fix my SHARP LC-46D77X Power Board DPS-286AP-1 A - a few notes here for people that search for this model
Symptoms: no power at all not even the Standby light.
I bought a replacement kit from ebay that didn't cover my model of TV but the IC as explained by Tom66 in the second post of this thread could be used so I thought I had nothing to loose. It was to be used as spare parts if this didn't work.

The IC7905 had physically blown its top off, so I replaced that first and nothing all.
resistor R7914 (to the left of the large transformer) was open so replaced that still nothing.
I removed R7918 and D7908 they seemd ok but replaced them anyway still nothing

I read on (re-reading a few times to try and understand) talking about the Zener Diode
I was getting all the good readings that Steinless was getting but not the bad resistance reading he had with the ENUV.
But I pulled one leg of the zenner anyway and the TV powered up.
So I have two questions now that I will post separately.

[mojos911]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Ok. So I have ordered from the site suggested and have DHL delivering. Lets see how we go. Thanks.

[R_J]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

This is the best I can do: https://www.chinahao.com/product/40080933014/
Good luck

[budm]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

That is going to be tough to find.

[mojos911]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

The idiot that I am thought that there might be an inline fuse under the yellow tape and when I investigated this I cut the winding's with my blade. I know rooky mistake I hear you say and yep that's me. I have tried to get another one as I want to try and fix the set. I been doing research on why the standby power is not coming on and when I tested for the 5v output on the transformer there was none even though there was an input voltage of about 317v so I thought that there was a problem with that component. Any suggestions who might sell them, as I have tried Digikey, shopjimmy and a couple of local places hear in OZ but to no avail?

[budm]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Is the transformer broken? in which way?

[mojos911]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Hi Everyone, one noob here and was wondering if someone had a good supplier for components. i'm especially having trouble find a new standby transformer for my DPS-286AP-1 Power Board. Any help would be great.

[Jeff1]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

The pin listing is right there to the the left of the PD connector.
PD-9: AC_DET.
You must report the Voltage readings of all the pins, you must put down the pin names and follow by the Voltage readings when TV is OFF and when the power switch is activated so we we can easily see the pattern.

Hi

I found a solution to the heat problem on the TNY264PN (IC7905)! I made a heat sink out of a piece of aluminium plate and bent it up to go onto the aluminium heat sink towards the bottom of the board and used a little bit of heat transfer paste between the top on TNY264PN (IC7905) and bottom of aluminium plate. Have ran tv all day now without a issue. Before I was getting maybe 3 to 4 minutes before it turned off. I know it's probably not the correct fix but is working for now. still unsure why it was getting hot but the tv is working fine apart from that TNY264PN getting hot

[budm]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

The pin listing is right there to the the left of the PD connector.
PD-9: AC_DET.
You must report the Voltage readings of all the pins, you must put down the pin names and follow by the Voltage readings when TV is OFF and when the power switch is activated so we we can easily see the pattern.

[Jeff1]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Please star a new thread with make and model name, then upload good clear pictures of the whole back side of the TV showing all the boards, the good clear straight shot pictures of the whole Top and Bottom side of the power supply board.
Does this board have AC_DETECT pin on the PD connector?

I can't sese it a AC_DETECT pin on PD connector but have noticed IC7905 is getting very hot before the tv turns off.

Sorry I just noticed auto correct changed board number should be DPS-286AP-1.

I seem to have all correct power voltages on the points I have tested until board seems to shut down.

Thanks

[Jeff1]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Please star a new thread with make and model name, then upload good clear pictures of the whole back side of the TV showing all the boards, the good clear straight shot pictures of the whole Top and Bottom side of the power supply board.
Does this board have AC_DETECT pin on the PD connector?

Thanks I will do that when I get home today

[budm]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Hi

I got a lc52d77x that has dos-286-1 power board but has different issues to this post as tv will power up run for a minute or two then turn off (including power light with no flashing) then turn back on after a minute or two then repeat over and over. Has anyone had this issue and know what is the issue. Everything works fine on the tv when on. When it shuts down you can hear a click from back of tv.

Thanks
Jeff

Please star a new thread with make and model name, then upload good clear pictures of the whole back side of the TV showing all the boards, the good clear straight shot pictures of the whole Top and Bottom side of the power supply board.
Does this board have AC_DETECT pin on the PD connector?

[Jeff1]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Hi

I got a lc52d77x that has dos-286-1 power board but has different issues to this post as tv will power up run for a minute or two then turn off (including power light with no flashing) then turn back on after a minute or two then repeat over and over. Has anyone had this issue and know what is the issue. Everything works fine on the tv when on. When it shuts down you can hear a click from back of tv.

Thanks
Jeff

[peanuts66]

Re: IC Number on DPS-286 AP/RDENCA336WJQZ Sharp power board

Hi, Just wanted to say thanks. The info in this thread assisted in a successful repair. Keep up the good work.