Convergence IC392-110 =? NTE7178?

d0ngta0 · Guest

Help!!!
I've a Toshiba 61" TV that will not come on and shut off after poweron. The LED in the front keep flashing. I've read the posting in this forum and took my chances with replacing two convergence IC392-110. I could not find this IC locally but there's an equivalent IC from NTE7178. It has the same exact specs as the IC392-110. After replacing them, the TV did not turn on, still click On then self click Off.

Help from anyone please who can guide me to the next step..... Thanks for reading

cory · Guest

model number?

Guest · Posted: Wed Sep 26, 2007 11:13 pm Post subject:

Cory,
I don't have that information with me right now. I am not with the TV but I did all that yesterday. I am looking for some common pointer to check out

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

Depending on the model, unplug the xray protect plug. If the set comes on, you know it's the convergence IC's. Also the 18vdc plug. And the STK's don't cross to NTE.

Guest · Posted: Thu Sep 27, 2007 1:14 am Post subject:

Minnie,
Before I replace the ICs, I did remove the reset wire from the bigger board, and all the lamps did turn on. I am not familiar with TV, so can you help me identify what is the Xray protect plug? Also what is the 18vdc plug?
Also the reason why I ask if the STK392-110 can be replace with the NET7178 is because I couldn't find any STK392-110 around and the only electronic store did said it cross reference to a NET7178. I've load the specs on both and the electrical parameters are the same.
Can you help me understand why you mention they are not compatible? I am attaching both specs if I could.
Thanks again for you reply

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

Guest · Posted: Thu Sep 27, 2007 5:11 pm Post subject:

Minnie and Cory,
I like to add before all of this, when the TV didn't turned on. I did try something like you said, by removing the Power/Reset circuit from the Main board to the Convergence board, and the TV did turn on with all 3 lamps working. However, I quickly smell a resitors near one of the Convergence IC burning. So I quickly pull power to the whole TV.
From this test, I learn not to do that since it did take out a Resistor, but I also know that the Bulbs are still okay.

AnyIdea why the resistor burn? I did measure it aftward and it's around 6Ohms... the color of the Resistor is Red,Red,Gold,Gold, so I taken it's a 2.2 Ohms with 2Watt rating.

Anyway, does this still sounds like a Convergence problem? I am afraid to bypass anymore protective circuit now.

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

Sure, the IC craps out and take resistor/resistors with it. These IC's control red vertical/horizontal, blue vertical/horizontal, and green vertical/horizontal. 3 verticals, 3 horizontals equals 6 resistors. The resistor is meant to fry to protect the vcc so you don't fry the source voltage/supply. Replace both STK392-110's, check all 6 resistors and change which ever resistors change from the original value. + or - .2 ohms is a big jump in this circuit. So if it's 2.2 and reads say 2.4 or 2.5 I replace them so it doesn't stress the IC's again.

D0ngta0 · Guest

Minnie,
You sounds like you have done this many times Smile

Must be an Admin here? Anyway, look at the TV again and got the Model number it's a Toshiba TP61G60 from 1997. After looking at these circuits again reminded me of college lab days, so I like to learn more on how TV works.
Do you know where I can get an electrical schematic for it? And where can I get the fundamental about projection TV? For example, I keep hearing about the coolant, what is it used for?

I will try to look for more burn resistor and update you on my status..
Thanks again for your inputs

D0ngta0

minnie · Joined: 18 Aug 2005 Posts: 2880 Location: Hell

The coolant is in the picture tubes. This should be as simple as replace the 2 STK392-110's and find the burnt resistors. This is a paper print so I can't pull it but if you read the resistors around the IC's, 1.8 ohm comes to mind.