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Panasonic PT-61HX41E clicks on then off, but no LED

I have a Panasonic PT-61HX41E that the power relay clicks when I hit the power button clicks again a few seconds later. No LED lights. I have looked around the D board and don't see anything that looks obviously burnt. There are some areas on the board that look like they have got hot over the past few years (diodes at top left of board, and small impendence coils near power relay), but the diodes still seem to be good, and the coils are not open. I am at a loss on where to proceed. Would love to have a case where the LED would let me know what to fix :)

I checked around for service manuals I could find with a schematic/foldout for the D-board (TNPH0371), but could only find one without that schematic.

Posted by avatar on Nov 04, 2009

    • By avatarsteven_mahur Nov 05, 2009

    • This is an 8-year old TV -- warranty definitely not an option, and the D-board is discontinued (can find for more than the TV is worth).

      Are there a specific set of components that typically fail to cause this specific symptom? That is, the LED doesn't even come on but the relay will still click on for a few seconds before clicking off.

      Issues with convergence ICs going bad, audio board issues, etc, seem to be reported by LED flashes on this model.

      Is there a place I can get a hold of the schematics for the D-board? I want to make sure that before I look into purchasing the service manual, that it really includes it. (I have found copies of it, but they do not include the D-board schematic.)

    • By avatarsteven_mahur Nov 06, 2009

    • Is Q1504 the HOT transistor on the TNPH0371 board? It has a part number that starts out with C4635, but I can't seem to make out the rest. I did find a service manual with a parts list on a similar panasonic model that had Q1504 as panasonic part number 2SC4635-YB7. Anyway, I am seeing around 8 milliohms from base to collector for that transistor. Also, the board appears to be very slightly darkened in that area (HOT runs hot?), but the traces still seem to be connected.

    • By avatarsteven_mahur Nov 06, 2009

    • I believe the HOT that you were originally referring to is Q551 (2SC5612LB228 per a similar panasonic TV part list). I haven't disconnected it to check yet, but will check tonight. Also, I believe the capacitor you are referring to is C501 - a 100uF-35V cap. If Q551 is the HOT, this may be an issue because at first glance, the 2SC5612LB228 part seems to be discontinued. Or at least not as convenient as desired (I usually drive to MCM to pick up the parts).

    • By avatarsteven_mahur Nov 07, 2009

    • As far as the HOT (TOSHIBA 2SC5612), I am showing 463Kohm between base and collector once removd.



      I removed the following caps and tested (appeared to be directly tied / or in series tied to collector of the HOT).


      Again, part numbers are from a PT-47WX49E & PT-47WX51E/CE manual, but I believe those models have the same D-board as the PT-51HX41E/CE, PT-56HX41E/CE, and PT-61HX41E/CE models. Also, I had to offset for the accuracy in my multimeter (without leads was 110pF).



      C522 read around 1780 pF
      ECWH20182JVY CAP,P 1800PF-J-2KV

      C523 read around 1780 PF
      ECWH20182JVY CAP,P 1800PF-J-2KV
      C512 read around 980 pF
      ECWH20102JVY CAP,P 1000PF-J-2KV

      C519 read around 230 pF
      ECKW3D221JBP CAP,C 220PF-J-2KVDC

      C519 read around 230 pF
      ECKW3D221JBP CAP,C 220PF-J-2KVDC



      I just noticed there are some more 2kV caps in the 5xx area on the board that I didn't test (yet) and are connected to the HOT collector, but the only one so far that is connected directly to ground and HOT collector is C512. The ground connects to C523 connects to C522 connects to HOT collector though. Anyway, I don't see anything too out of the ordinary yet.

    • By avatarsteven_mahur Nov 08, 2009

    • Following some other discussions I saw regarding similar TVs, I also checked out C509 and D503.

      C509 seemed to check out: (ECWF2474JSR CAP,P .47UF-J-200V) read at .470 uF



      However....D503 (FMV-3GULF730) was odd. From what I read, its a damper diode.
      Looking at the front of the diode, and numbering pins from left to right 1 to 3, I noticed the following:
      Its directly connected to the collector of the HOT on PIN 3, and connected to ground at PIN 1.
      The circuit board, faint labeling on the chip indicated 1-->|--2-->|--3 (and datasheets for FMV-3GU).
      1 to 2: 59 Kohm
      2 to 1: 13 Mohm****
      2 to 3: 4 Mohm
      3 to 2: open
      1 to 3: 5.4 Mohm

      In my nubie opinion, looks like D503 is blown as indicated by the 2 to 1 opening. If that is the case...is there something else that caused it to blow or that would have been blown if it went bad, or after 8 years of usage it just go bad and the internal circuit detection catch it before something else happened.

    • By avatarsteven_mahur Nov 09, 2009

    • As far as parts, it appears there are replacement/subsitution parts for the original discontinued ones, and also looks like sears direct parts has both (MCM has a back order for the damper diode).



      B0HBRV000001 for the damper diode, and B1BAJW000003 for the HOT (had lower than expected resistance when checked..going to replace it as it was probably damaged when the diode wasn't helping discharge the back-current building up on the transistor).



      I haven't ordered them yet -- want to hear your feedback before ordering. I am trying to limit amount spent on this -- don't want to make multiple phases of purchases going over the worth of the TV.

    • By avatarsteven_mahur Nov 09, 2009

    • Does anyone have access to the panasonic website to check for service tips for the PT-61HX41E model? Or really, any models that use the AP820 chasis (ex: PT-51HX41E, PT-51HX41CE, PT-56HX41E, etc)....or any similar models, such as and possibly PT-47WX49E/51E/51CE, that use the TNPH0371 D-board or similar power supply board.)

      I am going to try to check the power supply tonight or tomorrow.

    • By avatarsteven_mahur Nov 10, 2009

    • I detected 13.5 VDC at C812.



      If I am understanding correctly, the On/off command is definitely being applied, as the main power relay (T801) is engaging/clicking when the unit is connected and the power button is clicked, and then several seconds later clicking again (assuming turning back off).



      Note that when troubleshooting with rusty_etech, it appears we had found that the damper diode / D503 was leaky and appears to have caused damage to the HOT / Q551. (Question was if damper diode failed due to normal use, or had problems due to something else -- like 140V supply being incorrect, or damaged flyback, etc.)

    • By avatarsteven_mahur Nov 10, 2009

    • Correction on the source of the clicking -- it was RL801 that was clicking, not the transformer :)



      Is there still something that I need to check on Q802 given that RL801 is clicking (on and then off after about 10 seconds)?



    • By avatarsteven_mahur Nov 12, 2009

    • I am not seeing any voltages present for these diodes on the secondary side of T801. However, for that matter, I am not seeing any voltage on the input side of T801. I checked back at D801, which I think provides this section of the board with power (should be AC in/dc out - RBV-408 / bridge/rectifier). When the relay (RL801) engages, no voltage on either side (1&4 DC check, 2&3 AC check). I need to check some more/trace back (or just break down and buy the schematic) to see if its actually RL802 that has to engage before D801 has power...or if there is something else open.



      As far as the convergence amps, I don't think its even getting that far. I had assumed that to be the issue first (as I had just fixed two other TVs with convergence amp issues). However, it should be flashing LED if it was all the way over there -- I don't see any LED. I already had the STKs ordered before I started to troubleshoot this issue. Even though I was pretty sure it wasn't the source of the issue, I went ahead and replaced them as they seem to wear out over time.



      Ok, back to looking for the cause. If you have any pointers, let me know. By chance, is your panasonic access working again? I ask as it looks like you knew some of the diodes by ID.

    • By avatarsteven_mahur Nov 12, 2009

    • For D801 -- it does appear to be fed from RL802, which is not engaging.



      RL801 is though (could see change from 0 to 120VAC when it engaged).



      I still need to replace the HOT and damper diode, but wanted to get a parts list together first before putting any more money into the TV. That may not be possible if it turns out that some type of circuit check occurs when RL801 enganges of the HOT/damper circuit before RL802 will engage.

    • By avatarsteven_mahur Nov 13, 2009

    • I went ahead and ordered th HOT and the damper diode yesterday. Once I get it installed, I'll try the 100w lightbulb/fuse tests to hopefully avoid something burning out during initial testing....maybe then the second relay RL802 will engage so I can check out the 140V at the collector of the HOT and make sure its all ok before trying to check it out normally.

    • By avatarsteven_mahur Nov 17, 2009

    • D503 and Q551 have been replaced now. However, still same behavior. Also, as far as the 100w light bulb test, it doesn't light up from what I can tell (it is being used, as when the bulb is removed from the socket attached to teh wires to the fuse holder, RL801 doesn't even engage). What else can I check to find the cause of RL802 not engaging? Is there some way to check out the flyback?



      Thanks for any info.

    • By avatarsteven_mahur Nov 17, 2009

    • Oh, and I have the service manual now (chasis AP820)

    • By avatarsteven_mahur Nov 18, 2009

    • Glad you made those comments -- the termal fuse and bypassing the relay. It looks like R800 is reading open...which means the circuit wouldn't be able to do the pre-checkout before engaging ye old RL802.



      I am still leaning towards an issue at the flyback/hot/damper level that caused R800 to short out...does that sound right?



      Just to check another component that some others discussions on other websites indicated may have issues related to r800 going bad -- I also pulled Q801 (chopper transistor?) to check it out -- and I don't know what I should be seeing when disconnected (it read open between all pins/directions except S->D @5.9Mohms).



      Anyway...going to order R800 (ERU5TCK1R5T).

    • By avatarsteven_mahur Nov 20, 2009

    • As the board is discontinued, its pretty expensive to replace the whole board (300-500 for "recycled"/refurbished). This was a "free TV" from a friend and I was shooting for < 150 to fix. I am going to be just over 100 with parts, shipping, and supplies (heat compound) assuming that once the R800 thermal fuse is the last piece in the puzzle. I guess I will know in a few days once the replacement for R800 comes in.



      In the meanwhile, for the chopper transistor, did the readings I provide seem to indicate it was still good?

    • By avatarsteven_mahur Nov 21, 2009

    • I replaced the R800 thermal fuse resistor. The 100w lightbulb test (supposedly can be done with other sets) didn't seem to work as well with this set; sounded like RL801 enganged, RL802 engaged, then both clicked off. So, I just went for the full test. With the fuse back in instead of the 100w light bulb, both relays stayed engaged. The TV powered right up, the sound was good, the picture was good, and even the LED light on the front works :).



      None of the components seemed to be running hot after a few minutes of testing, so I am going to consider this one fixed with:

      1) Replacement of leaky D503 (damper diode)

      2) Replacement of low resistance Q551 (HOT)

      3) Replacement of blown/open R800 (thermal fuse resistor before main power).



      Thanks to "welcomejee" for some good areas to check, and A LOT of thanks to "rusty_etech" who really pointed out the faulty components. I am going to accept welcomejee's response as (to my dismay) the fixya.com site does not present me with an option to select rusty_etech's solution due to an "Ask another expert" that I had to do at one point when working with rusty_etech when the schematics were not available.



      Thanks again rusty_etech for all your help!!!

    • By avatarsteven_mahur Nov 21, 2009

    • Yes, it was helpful to get going in the right direction; however, the responses from rusty_etech pointed out the real solution.

Solutions (6)

Best Solution

Check +7 volts (standby) at C812 470UF/25V at power supply (D) board.
AC On-Off command applied to Q802 to engage relay RL801 to turn on main power supply.
Please let me know your findings to proceed.
Thanks.

Check the horizontal output transistor for shorts. Collector to base should check around 1kohm. Collector to base will appear shorted because of a resistor inside the transistor. Is the power supply coming up after the click?

    • By avatarRusty Campbell Nov 06, 2009

    • My subscription to Panasonic website has shutdown thiis morning so I can't look at the schematic either. If the horizontal output is checking that low I would say you have a problem right there somewhere. First off, disconnect the HOT and check base to collector again. If it checks good you may have a parallel component shorted namely an HV capacitor. Look for the little blue ones. I have seen these short. This set also has 2 HOT's. One is for the horizontal yokes and the other is for the High Voltage transformer. I'll keep looking for the schematic. Thanks for your patience.

    • By avatarRusty Campbell Nov 06, 2009

    • Do check the 100uf/35v but the caps I am refering to will be right off of the collector of the output transistor. These are usually brown or blue ceramic disc caps that are rated at 2kv or higher. They set up the horizontal frequency and deal with 1600v horizontal drive for the HV transformer. They normally go to ground right off of the HOT.

    • By avatarRusty Campbell Nov 09, 2009

    • Have you monitored the 130v source at this transistor? I am wondering about the power supply. If there was a short in this circuit(HOT) there would be no doubt. Try turning the set on and make sure the power supply on both outputs isn't momentarily coming up. You'll have to be in position when you press power because it is going to come and go quick. I still can't get on the Panasonic website so I to am at a loss. You might want to get one of the other specialist on this one. There is probably a service tip out there somewhere that would help you. Rusty

    5. View More Comments

If you have warranty coverage, I suggest you get it in as quick as you can.

The relay clicking is the power ON and OFF relay. It is controlled by the power management circuit. The failure it this: The power protection circuit has detected excessive current drain from some part or section of the tv that is dangerous. It has sent a signal to the power managment circuit telling it to shut down the power; the relay is opened and the power is cutoff.

You can unplug the tv for a few hours and try again, but I don't think the reset will cure it. Worth a try, but if it does not help, then you will have to have exercise the warranty.

The excessive current drain spoken of above is usually something to do with the deflection system or display high voltage, but can be from the audio amplifiers or the main power supply as well. The only way to know for sure is to have an expert do a physical inspection and diagnosis for you.

could still be an onboard fuse or the relay itself is not connecting its operating contacts. Buzz from the pins thru each other, if there are 2 coil-power pins then the rest (4) are just 2 straight switches so they should short thru between each pair, you should be able to measure supply voltage on the feed pair when the relay is not energised and work out from that what the other pair are, and one goes to each supply pair.

You could bridge the output pins into two single connections and the board would power up if thats the problem.

Check all over for hidden slow-blo glass fuses though...

the board on which components looks good.normally there is a problem in circuit tracks.the circuit gets cuts in many internal positions.so the board needs to be replaced.many times replacing the components on the board does not helps but replacing the board is necessary.
you can get the required board ,component parts from
www.partstore.com
This will help. Thanks please keep updated.please do rate the solution positively .thank you for using fixya.

If there are burn marks on the system board, it is likely that the capacitor or whatever component is there is burnt out as well. You can test most components with an ohmmeter. Most components are 25-30 ohms and 5 volts. It may be easiest to replace the entire board.

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