Basic Fuse Question Philips TV

[edy]

I'm working on replacing the parts and I am confused as to D608 replacement, and also D607. The original parts were BLACK with a GRAY stripe, labelled IZB36 BL and IZB27 BL and looks like a regular diode like you'd see for the 4 rectifying diodes. However, I assume it is a Zener as it is labelled IZ. The replacement parts from ShopJimmy are smaller and orange colored with a black stripe, and labelled U7 53A IN (as far as I can see) which look like a typical Zener.

Is this just a manufacturer difference? I can't find the exact part number of the new part online but it looks like it should be it. I also tested the old diode part on the "MTester" and found it was showing up as a resistor (it was a dead short remember), whereas the new diode part was correctly identified as a diode.

[edy]

Success!!!! Thanks everyone!   

So I ended up replacing ALL components that were provided in the Repair Kit (all 13 of them), as I knew already 3 or 4 were faulty on the board and then I figured I'd just unsolder the remaining ones since I had replacements anyways. In the process I found a few more bad ones.

Here are all 13 components provided in the kit and which ended up being BAD or GOOD on the board:

1 Resistor  (R611 *BAD)
3 Transistors (Q501  *? can't test it , Q601 *BAD, Q602 *BAD)
8 Diodes   (Bridge Rectifier: D601, 602, 603, 604, *all GOOD)
                (D607 *GOOD, D608 *BAD, D609 *BAD, D653 * BAD)
               (by the way I would have never suspected D609 or D653)
1 Capacitor (C605 * PROBABLY GOOD but I changed it anyways)

As you can see by the attached images, I used the DIM BULB TESTER which I made thanks to your help here on the forums. I started off with a 25 WATT bulb.... Light went on for a second then off.... And TV was trying to "boot" but would not start (status light would power up, then off, then on, then off and show "Philips" for a moment on the LED screen).

Then I went up to a 40 WATT bulb... same thing... Bulb on and then off a split second later, and TV looked like it wanted to start but would cycle on/off the screen with the startup logo.

Finally, placed a 60 WATT bulb and TV powered up!!! And the bulb had a faint glow on it, as you can see by the attached photos. The TV ran well and I'm using it now.

All in all....

$5 in blown fuses
$25 in parts/shipping from ShopJimmy
$15 for the ESR/component tester
$25 for parts to build Dim Bulb Tester
A whole bunch of time troubleshooting...
------
TOTAL: $70

Learning a ton of concepts on electronics repair.... PRICELESS!

(By the way, my wife couldn't wait for me to fix this thing as she needed it at her office... so meanwhile I bought another TV of the same size for $135... so this repaired one will be an extra we needed for home anyways).

[edy]

Hi folks, Just wanted to let you know I shared my story with Shopjimmy and mentioned EEV BLOG here:

https://www.shopjimmy.com/repair/share/story/id/262/issue/Philips-22PFL4907-F7-No-Power/

[Vito_R]

Congrats on your successful repair.   

[edy]

Hi everyone,

I've made a SUMMARY VIDEO of the entire repair here. Thanks again to everyone for their help:

[miguelvp]

Nice video, concise and to the point

[edy]

I looked up your part number and found this:

http://www.shopjimmy.com/catalogsearch/result/?q=EAY37228901

Is this it? The site lists a bunch of parts and substitutes so perhaps one of those will have a schematic available to download, or you can source parts or kits for repair.

Also check here for service manual:

http://www.eserviceinfo.com/downloadsm/37727/LG_32LC7R--32LC51--32LC52.html

And look here:

http://www.scribd.com/doc/48670580/LP78A-Ch-32LC7R-32LC51-32LC52#scribd

The document you are looking for is titled "LP78A Ch_32LC7R_32LC51_32LC52_.PDF". Sometimes you do a bit of investigation on Google and even though you can't find the manual it will let you find other search terms that you can look for and then you search using them.

I downloaded the PDF on Scribd and have confirmed it contains schematics, part numbers of all boards, with block diagrams and so on. It is a service manual. I will try to break it up and post it here.

[edy]

Here are the first sections (I had to split it up into 5 page segments due to upload size limits).

[edy]

And now the next chunk of pages.

[edy]

Here's the final part of the service manual... lots of schematics.

[Vito_R]

I replaced a fuse in a broken TV I have, and the NTC thermistor blew its arse out in spectacular fashion. So the advice about not just replacing the fuse is worth following.

Would a 200 Ohm resistor made out of a chain of 10x 20 Ohm 5W resistors be satisfactory for discharging power supply capacitors? A 400V cap would discharge at a peak of 2A. Which is a peak of 800W, but would it be for short enough time for the resistors to handle. I have such resistors on hand. I have heard a light bulb is also a good method. I'm too chicken to be shorting them out with a screwdriver.

The 200ohm resistor should be fine.  I usually use a 100 ohm 10watt resistor to discharge caps with 2 insulated alligator clips on each end.  Don't short them out with a screwdriver, that can potentially damage other parts on the board in certain situations.