Re: Vestel 17IPS20P pulsating
It was R242 that exploded and I erroneously replaced it with 10 Ohm. R311 is the one I checked to get the correct value since the two sub-circuits are basically the same configuration.
R370 and R228 are two 0,33 Ohm beefy resistors, the values reported are all wrong.
Also about half the components are missings on my board, these schematics are really odd.
otousama
Member
Last Activity: 07-24-2023, 01:37 AM
Joined: 04-04-2018
Location: Firenze
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Re: Vestel 17IPS20P pulsating
Hey there, I've got some news.
The TV is working again, good news! I'm a damn idiot, bad news!
I'm gonna report here my mistakes so that someone else can learn from them.
This morning I tried again to check the U202 surrounding components, with the scope I saw it trying to boot, but it never completed the sequence and remained stuck in a cycle.
Then it struck me... Did I use the correct values for the destroyed components? The schematics is useless in this respect, random values all over the place, so I checked...Leave a comment:
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Re: Vestel 17IPS20P pulsating
No no, the 12 and the 24 Volt rails are both down, only pulsating a little during the clicks. The only time I saw 10 Volts on the +12VCC rail was after connecting the mains supply and leaving it click for a couple of minutes, it then stopped clicking, turned on the backlight, showed the logo and went in standby. Now, and only now had 10V on the 12v rail, but it was still malfunctioning, there was a buzzing coming from the transformer and the TV did not turn on when the button was pressed, it only started the clicking cycle from the beginning.Leave a comment:
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Re: Vestel 17IPS20P pulsating
I did mean this with
Anyway, tried with the resistor but no luck, same behaviour, few hundred mV on the 12 V rail.
I'll call it a day, thanks for the patience, tomorrow I'll try to poke around some more before using the hammer....Leave a comment:
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Re: Vestel 17IPS20P pulsating
No idea, maybe it's the logic board that controls the ST_BY line once booted?
The TV used to fully switch on everytime the mains was plugged, showed the LG logo and 2 seconds later switched off with the red standby light glowing.
Q212 doesn't seems to be bypassed, there is no continuity between +12VCC_S and +5V_STBY.
I'm guessing that the power supply is not able to perform the initial boot, can't even pull up the +12VCC line, the logic board shouldn't be involved at this stage.
This is the back of the board,...Last edited by otousama; 02-20-2019, 04:07 PM.Leave a comment:
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Re: Vestel 17IPS20P pulsating
Maybe this board is a little different from the reference, the section for generating +5_STBY is not populated, Q212 and the surrounding components are missing.
Attached the screens on the pin 13 of TR200. Apart from the huge negative spikes there is a positive voltage of 12V. U202 is trying hard to boot up it seems....Last edited by otousama; 02-20-2019, 03:21 PM.Leave a comment:
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Re: Vestel 17IPS20P pulsating
Swapped U200 with U301 and replaced C240, same issue.
At the moment I'm trying with the vestel board alone. ST_BY should be present at all times for the +12VCC to show up? When connected to the logic board the behavior is the same.
With pin 3 I meant the REF pin, on the node with R255 and R211. But I doubt I'll find anything near 7V, since +12VCC is not present.
Only the clicking sound is always present, it is somewhat similar to the sound emitted by the electric fence energizers during discharge, a toned...Leave a comment:
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Re: Vestel 17IPS20P pulsating
Could try swapping with the octo for the backlight.
On the pin 3 of the U203 there are pulses of around 340mV, don't know if correct.
Tried swapping D214, same thing, but there is something strange about VCC_MAIN, it starts at 2V and slowly crawls pulse by pulse but VCC_M, later in the line goes well over 14 V from the beginning.Leave a comment:
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Re: Vestel 17IPS20P pulsating
Tried with a couple of values: (0,22 - 0,33 - 1) Ohm
The original resistor was 0,33 , the schematics says 120.
Did also change the mosfet with a FQPF12N60C, old one was MDF4N65B.Leave a comment:
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Re: Vestel 17IPS20P pulsating
Couldn't edit the post, I managed to write the wrong numbers for the damaged components...
The correct ones are:
U202, S536, Q211, R217, R242, R228, D201, D208, D522, D523Leave a comment:
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Vestel 17IPS20P pulsating
I've got this unlucky board, a Vestel 17IPS20P (150313R3) that got a couples surgeries during its lifetime. The last time I fixed it there was a blown diode (D208), nothing extraordinary, happened already two years ago, changed it and everything was fine. Then after about a month I had the [I]brilliant[/I] idea to add the unpopulated diodes D207 and D505 to harden this weak spot. During this operation I must have splattered some solder on the HV section cos after closing the lid and giving power a loud boom happened.
U202, S536, Q211, R230, R22, R242, D201, D208, D228, D522, D523... -
Re: Whirlpool washing machine board issue (MINISEL 600)
Yeah, those terminals got very hot. Before completely failing the washer was willing to start the cotton 60c cycle (only this one, that couldn't be stopped or modified) but then one time it got stuck heating the water till I noticed quite some time later and stopped working altogether.
Already tried cleaning the contacts, changed the ICs on the panel board and tested with a decade resistor box in place of the frontal knob, the one that let you select the washing cycle. The voltages...Leave a comment:
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Re: Whirlpool washing machine board issue (MINISEL 600)
I tried to install the board, right after firing it up the interlock blocked the door and something inside the machine was making a hissing noise, didn't respond to inputs.
Then after examining the board and testing all the triacs I decided to leave no stone unturned and... test every single component.
The results were meh, C1 and C2 (100nF) measured 24nF and 44nF. Both X2 caps that I guess are for filtering and nothing more.
So, if the issue was the board, it must be a fried MCU, if it wasn't the...Leave a comment:
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Re: Whirlpool washing machine board issue (MINISEL 600)
Ooops... Re-soldered the quick con and almost all the other joints. Tomorrow I'll test it on the washer.
Great! I couldn't find the schematics for this model. Now It looks like I can stop randomly poking around. Q2 has to be checked again I guess, the charred connector happened after i tested it.
Edit: Transistor tester recognized Q2 as a triac with Vf=.77V. It should be ok....Last edited by otousama; 04-18-2018, 03:06 PM.Leave a comment:
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Whirlpool washing machine board issue (MINISEL 600)
Hi there, I'm trying to fix an issue with my washing machine (Whirlpool AWG865) and its control board, namely a MINISEL 600 85SX-85DX-45DX (attached photos). The issue started with the machine refusing to accept a change in the washing cycle selection, it was stuck in cotton 60c and turning the potentiometer on the front wouldn't change the selection. Then after a few days in this condition it began to get high water temperatures and the board got a little charred near R54. I'm at a loss here, I did try to test some of the obvious components (capacitors, diodes, triacs...) but couldn't find a... -
Re: New Members - please post your introductions here
Hi there! To be honest I'm only writing this to comply with the rules (I don't like introductory threads, I'm shy
) but since I'm here I may aswell write something meaningful. So, I'm into repairs and usually I "lurk" around trying to find a fix or a hint, this time I wanted to try with the help of a wider audience hence I'm here.
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