Re: Philips 32PFL3505D/F7 No Power
Pretty sure...that "100 volt zener diode" right off of the output of the B+ supply on the inverter board is for a CROWBAR..as a "just in case" the B+ goes out of control. This is so it does not get to a catastrophic level. The zener WILL SHORT...if the voltage tries to go much above the 100 volt level...and shut the set down altogether.
Control of the b+ level is established through Q-1970...which controls an optocoupler IC-1930.. A voltage divider off of the B+ line, along with zener d_1970,...
RCA2000
Senior Member
Last Activity: 07-22-2018, 07:32 PM
Joined: 09-03-2014
Location: Cincinnati Ohio
-
Re: Philips 32PFL3505D/F7 No Power
And the CAUSE.. of the shutdown, which is due to the inverter B+ going to OVER 100 volts..(when it should be 82 volts)..is a BAD Q)-1970 transistor.
If this transistor is checked it WILL likely show Ok...BUT..it is failing in a THERMAL way..when it is COLD..evidently it does NOT conduct enough..allowing excessive voltage to the optocoupler IC 930..as it WARMS up...this voltage WILL DROP..but NEVER quite to the 82 volt level..more like 90-93 volts..but MAYBE low enough..to NOT cause shutdown.. I suspect this is why the set will "sometimes...Leave a comment:
-
JV C EM65FTR tv..Wide bae in picture--common issue?
I have seen a few of these sets..and they seem to have some issue of a wire bar in pix, right of center.. has anyone seen this and is it the T-con, signal board..or PANEL? I know of FOUR Of these with the SAME EXACT problem--someone has.. The bar is mostly black..with an edge of whitish on the right side.. probably a FOOT thick, running form top to bottom..
Has anyone seen this?Last edited by RCA2000; 02-08-2017, 10:09 PM. -
Re: an embarassing question (LG, 47LB5900 I think)
No...you can see most all of the LED's..depending on the ANGLE..at which you look at the set.. Now..a LOT of those fragile lenses DID pop off, just TOUCHING them causes that...but we successfully glued them back on. If you look from the top, you can see most of the leds on top, from the bottom, the reverse.. The replacement leds look a bit DIMMER In fact...than the old ones do..not much but a bit. Dimming the BL HELPS...but even at 20% ..you can STILL see them through the panel !!Leave a comment:
-
an embarassing question (LG, 47LB5900 I think)
I have a request. Kinda ashamed to even have to ask this. I was helping a friend repair bad LED strips on this set. We were successful. FOUR bad LED..on 4 different strips. BUT...upon re-assembly..SOMETHING went wrong. This has NEVER happeend to me before--and I have successfully done a number of BL repairs, both LED and CCFL.
We put all of the successive layers back behind the panel...checked the BL.. BEFORE re-assembly...and NOW.. you can EASILY see a BUNCH of the individual led's as "bright spots. with the panel on ..it DOES show BADLY.
We had the sheets... -
Re: Vizio VO47L FHDTV10A No display
I also had a VO47L set...with the "no raster" but power..problem. It was a freebie from CL. I grabbed it figuring it might be saveable...and if not...I would part it and sell the boards and stand.
I comfirned the problem...checked my PSU voltages...i run mode...all looked ok.. The sinks on the cold side of the PSU did not seem to warm up much...but I figured that was because there was no BL. So...I turned my attention to the BL inverter. this set has a pair of them ..a "master and a "slave inverter. After removing...Leave a comment:
-
Re: Element ELCHW402 - Will not turn on!
You may never know just HOW helpful your post has been !! I had a PAIR of these boards.....with this "intermittent no-start problem. these caps...along with C-814, 100/35V.,(filters the "start supply" for N811,) for insurance..FIXED the problem !!...Leave a comment:
-
Re: Sharp LC-52D65U--1 blink lamp error--cannot keep on.
Ok...here are a few pictures. One if of the back of the set. Not much to see...the signal board, T-con, PS and inverters..that's it.
A couple are of the inverter one shows the # on the inverter top board (the one with the drive ckts on it..the bottom is just a "slave".. One pic is a close-up of the area around the drive IC area on the main inverter..
Sorry...my phone camera is not very good...and zoom does NOT work. this is the best I can get. Hope it helps.....Leave a comment:
-
Sharp LC-52D65U--1 blink lamp error--cannot keep on.
I have this Sharp LC-52D65U set--and all I get is the 1 blink..which means lamp error. If I do the Input and volume down...it TRIES to come on, after a few seconds--I get a quick blink of the raster--then it goes down...BEFORE I see any sort of menu , etc.
I unhooked the error line from the master inverter--did not help. Obviously--the inverter is shutting down of its own accord. I have read there is a capacitor you can bridge that will keep the inverter from shutting down--and then you can see if you have a bad CCFL tube, etc--and see if the rest of the set works.
... -
Re: Panasonic TC-P42S30 - Would someone mind helping me confirm SN?
TW_-you seem to be very knowledgeable on PDP sets...So is it NOT advisable to buy boards form a broken screen plasma set ?
WIll it hurt MORE than the Y-buffers--I KNOW from the sound of a busted panel--is sounds like it is HARD on them...the loud "buzz" they make... WIll the Y-sustains (or sc board) get whacked ALSO? How about the Z_(or called SS or X in some sets ) ALSO get killed in a busted panel?...Leave a comment:
-
Re: Samsung LN46D630M3F, TV powers on, sound works but no backlight
Are you getting boost converter action--when the set is turned on? You will NOT see this in standby. The PFC ckt ONLY operates in the RUN mode--to reduce current flow and (theory--at least) power draw of the power supply. There should be close to 400 V dc on the filter caps in the RUN mode--around 160 or so in standby. 160 is NOT enough...for run...Leave a comment:
-
Re: Panasonic TC-P42ST30 14 blinks.
I just looked at the diagram (block diagram) of the power supply lines--and the F15V line needs to be checked...if it is NOT there from the P board...you NEED to know that...before you replace anything..
The "blink code list" is NOT always perfect. Sometimes...you need to narrow things down on your OWN...with a meter ..voltage/resistance tests..Leave a comment:
-
Re: Panasonic TC-P42ST30 14 blinks.
WEll...the manual says a 14 blink code is a loss of the 15 volt supply. I would check and see if you are getting it from the P board (power supply). It is POSSIBLE I reckon a shorted SN board loading the 15 volt line can cause this. if so...unloading the SN board and checking the source at the P board at turn on should confirm this,. P_6 on the P board--pin 10 and 11 should be 15 volts..leads to the A board.Leave a comment:
-
Re: Samsung LN46D630M3F, TV powers on, sound works but no backlight
USUALLY...a BL that "lights for a couple of seconds and then drops...is the fault of the BACKLIGHTS--be they CCFL tubes of LED"S.
Show a rear pix of panel with all boards--and I will get a better idea of things to go on...Leave a comment:
-
Re: Samsung plasma PN50b430 maldischarge
I would look farther on the Y-Sustain board--since it DID have some bad components. Likely something else is STILL bad there..
Maybe you should try and grab a known GOOD Y-Sus baoard...and see how that works. because if you foi NOT get clean red, green and blue alternating rasters with the TP jumped...it rules OUT the signal board and all before it. Your raster looks a LOT like a bad Y-SUS board to me...
I do NOT believe you will get OSD with the TP jumped--alternating colored full rasters I think.,.Leave a comment:
-
Re: Panasonic Plasma TC_P42U1
I saved EVERYTHING..including the filter glass (which is NOT cracked or even scratched- still in the frame), all boards, wires and ribbons, speakers even the IR and power switch board..
ONLY the bare bad panel, a few brackets, and rear cover will go to the garbage !!Leave a comment:
-
Re: Panasonic Plasma TC_P42U1
They are fine. Sound is great. Tunes fine too. looks like some of these boards are in HIGH demand--if good...and I KNOW mine are...
A, SC, SU, SD and P board...seem to be needed...not so much SS (because they are NOT often a problem..but a Little bit..) I DO wonder if my "C" boards are ok though...seeing that blown Driver chip on that one address line...not a WHOLE lot of active stuff on them...but there is SOME stuff...that might not have liked that shorted chip too well..Leave a comment:
-
Re: Panasonic Plasma TC_P42U1
Does NOT matter now. Just checked it... Bad PANEL...have a pair of vertical lanes BLANK and VERTICAL lines throughout raster. it also shut down ONE time--with 5 blinks. Tried cleaning address buffer connectors...but ONE of the little chips--on a connector where a lane is missing...has a "bubble " in it...BLOWN.. and the buffer next to it...gets TOO hot,,
Oh well...at least I DO have good SC, SC and SU and SD boards..along with the power supply and signal board.Leave a comment:
-
Panasonic Plasma TC_P42U1
I grabbed this Panasonic plasma tv last night...It is a TC-P42U1 09 model. Have not looked at it yet. Need to know if anyone here has the 09 year panasonic PDP service guide (I HAVE the 10 and 11..but not 09.)
if it IS an SC or other scan problem...SC boards are NOT any cheaper on-line for this one--than for the 50G20 series I found out. But--we shall see.... -
Re: What to look for that blew UPS MOSFETs?
On my own APC ES-750UPS..I was AFRAID...I might have a sort of SMPS issue...beacuse very recently...it got to where it would NOT hold the load of the computer even for a BRIEF SECOND..and would drop out...crashing the computer when it did. BUT..it WOULD run with SMALL load...like the Cable modem.. I was afraid MORE was wrong than just a dead battery...but I HOPED that was all that was wrong..that the battery was dying and not strong enough...it made sense that was the problem...not too mention it had been in there a LONG time...
...Leave a comment:
No activity results to display
Leave a comment: