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#21 |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() ok thanks will do .i will post results
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#22 |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() Well tiny tps54319 ic arrived
removed s/c one checked all pins for s/c on board, prepared board fitted replacement , checked resistances i/p pins 1 and 2 had 5k to deck which was caused by zd2403 on 3.3v i/p powered up ,standby led ok 3.5v ok powered on no o/p from i/c no 1.5v on pins 10,11,12, no backlight no short on o/p so i suspect enable pin 15 not turning on this is proving to be a headache not giving up yet though trying to work out the start up sequence |
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#23 |
Badcaps Veteran
Join Date: Aug 2015
City & State: Cardiff
My Country: Wales
Line Voltage: 230V AC, 50Hz
I'm a: Hobbyist Tech
Posts: 6,544
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![]() The data sheet says "pull below 1.2V to disable" so I gues a voltage greater than 1.2V will enable it.
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Willing to help but I'm no expert. |
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#24 |
Badcaps Veteran
Join Date: Jan 2016
City & State: Sochi
My Country: russia
I'm a: Knowledge Seeker
Posts: 852
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![]() The microcircuit may not fit well on the seat, it will not contact.
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#25 |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() removed ic checked all print connections
cleaned underside of ic, retinned the print refitted ic. same as before except i now have .2 volts on o/p pins before i had 0v on o/p enable pin has 3.2v on it im going to try another ic in case i used too much heat to flow the solder. (clutching at straws) i preheat the board underneath to approx 200 deg then fit chip then use s/station to melt solder and wait for flow i suppose something else on panel could have been damaged due to original faulty psu putting out more than 3v this is why the 5v zener failed |
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#26 |
Badcaps Veteran
Join Date: Jan 2016
City & State: Sochi
My Country: russia
I'm a: Knowledge Seeker
Posts: 852
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![]() See the diagram for what else the standbay + 3.5v_ST bus powers
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#27 |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() some progress .
i supplied 1.5v to o/p and tv works ok so as Lotas said chip must not be seated correctly this has been my first time working with these sub minature ics i suppose practice makes perfect .ive ordered a couple more of this ic and im ordering another type of liquid flux ive used the same flux for years without any problems it wont do any harm to try another flux i will report back with results |
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#28 |
Badcaps Veteran
Join Date: Jan 2016
City & State: Sochi
My Country: russia
I'm a: Knowledge Seeker
Posts: 852
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![]() You may also have suffered a MICOM (standby controller and it contains the firmware that controls it) 33 pin. gives the command to turn on just on it.
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#29 | |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() Quote:
but as tv works fine with 1.5v injected from bench psu i assume ic is not making good contact , or i may have damaged it with too much heat i have ordered another |
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#30 |
Badcaps Veteran
Join Date: Apr 2013
City & State: cheshire
My Country: uk
I'm a: Knowledge Seeker
Posts: 390
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![]() while i am waiting for chips to arrive ive been running tv with a LM317 as shown in pic
i know the original chip is rated at 3 amp and the lm317 is 1.5 amp the 2 resistor values allow correct 1.5v o/p i just wanted to confirm tv had no other problems ,and it seems fine. the temporary reg only gets slightly warm dont understand why pic is upside down? |
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