[m109ner]

I'm looking at replacing the IC chips, again, on a Hitachi 57F500A. It originally came with IC chip # STK392-150. I bought a new set of Sanyo STK-394-160's and installed them. The TV was having convergence problems but I was getting Video and Sound. After replacing the old IC's with the new 160's, I get no video nor sound. The red Power light on front panel goes on but no video nor sound. All connectors are on correctly as I've triple checked them, and all of the board jumpers are connected correctly. After an extensive lookover I'm reverting back to the original 150's.

I'm also looking at replacing the resistors and was hoping for someone's help on this board to assist me with the resistor numbers to repalce and the ohm values for each. Also, if someone has the schematic for the IC chip board, I'd really appreciate that too.

Thanks very much in advance.

 

[lcaillo]

You need to verify that you didn't blow a fuse. Check the pico fuses in the PS. If you did not let the PS discharge and shorted a supply that had some residual charge, you could have blown a fuse (or trashed a chip). Otherwise, fire up the set with no ICs in it. If the chips are bad, it should run without them.

 

[m109ner]

lcaillo,

Thanks for the quick reply. I wll check the PS pico fuses to see if any are blown.

"Trashed a chip"? Did you mean an IC Chip?

Assuming that the pico fuses are not blown. If I pull the IC Chips, connect everything back together w/o IC chips, and turn the TV back on, I should get video and audio? Correct? This would indicate bad IC chips?

Thanks

 

[lcaillo]

Start with the basics. If you have blown a fuse the set will likely shut down because that supply is low. Don't make assumptions nor guesses when there are checks to be done.

 

[m109ner]

Agreed. I'll check the PS Pico fuses and report back.

Thanks

 

[m109ner]

lcaillo,

I'm finally going to get a chance to test out the Power Supply PICO fuses tonight. Would you happen to know what the values are for these? I figured I'd stop by my local Fry's store and pick up some replacement fuses so that I have them handy in case I run into some blow fuses I have them available. They're cheap enough that if I don't need them, I'll just have some extras.

I don't have the service manual for this TV and was wondering if you had that informaiton available?

Thanks for your help.

 

[lcaillo]

I don't recall. Some sets use 2 or 3 amp fuses, some use 5 amp. I just keep an assortment in my box and replace them with what is there when I need them. They are labelled.

 

[m109ner]

lcaillo,

Please see attached pics. After testing the round cylindrical, glass fuses for continuity they were fine. I'm not sure if these were the "pico" fuses you were referring to or if this was correct testing method. But I noticed that the green #928 LED did not turn on when the TV was plugged in and turned on. All other three green and one red status lights did turn on.

As you can tell, I'm new to this, but I was previously successful in de-soldering and re-soldering IC chips into my Toshiba RPTV and two years later it still working great. So, I know I can do this with a bit of help and guidance.

Any help that you or anyone on this forum can provide, I'd really appreciate it.

Thank you.

 

[lcaillo]

Pico fuses are not glass. They are yellow/orange or green, sometimes black, and are shaped like a resistor. I do not recall which circuit that particular LED indicates a problem with, but my guess is one of the convergence supplies.

 

[m109ner]

Icaillo,

Took your advice on the description of the PICO fuse and found that E907 was open. What are the chances I can find this type of fuse say at a FRYs electronics store or Radio Schack?

 

[lcaillo]

I never looked for them there, so I wouldn't know. You could call them or look online...

 

[m109ner]

Icaillo,

Sorry for the late follow up post. Thank you so much for recommending to test the PICO fuses. Sure enough, after testing them I found one that was open, E907.

I finally got around to buying the 3000mA pico fuse, installed it, and BINGO!!!! Green status light turned on and video/audio is back.

Thanks for all your help!! :yay::yay::T:T