I've been searching the net for a block diagram of my ViewSonic VB50HRTV tuner, because one day I turned it On and, after a strange messed up display, it simply blows-out. Then i've opened it and found that an IC on the board (U69) just exploded.
I think it is a 74HS04. Could anybody help me ??
Thanks and excuse me for my bad English (I think... )
I think it is a 74HS04. Could anybody help me ??
Thanks and excuse me for my bad English (I think... )
Heya buddy, have a look here at this site:
http://eies.njit.edu/~hou/manuals/ECE394/Toc.pdf#search='74HS04'
It seems to be a logic gate IC. Why it blew who knows (as i cant see the circut). It could be a power issue on your board somewhere like a faulty reg or cap. Normally these things dont just burn up, and when they do its because of a faulty power issue. Check your grounds and follow the power circut to the chip to try and find the cause, then once the cause has been recitified and repaired replace the chip.
If that isnt the correct IC, it could be more then likely be a PLL IC. Once again i cant see the circut so i cant be of much help.
Trev 🙂
http://eies.njit.edu/~hou/manuals/ECE394/Toc.pdf#search='74HS04'
It seems to be a logic gate IC. Why it blew who knows (as i cant see the circut). It could be a power issue on your board somewhere like a faulty reg or cap. Normally these things dont just burn up, and when they do its because of a faulty power issue. Check your grounds and follow the power circut to the chip to try and find the cause, then once the cause has been recitified and repaired replace the chip.
If that isnt the correct IC, it could be more then likely be a PLL IC. Once again i cant see the circut so i cant be of much help.
Trev 🙂
Thanks for the info. I reviewed the board and the power source for cold solder joints, faulty pieces and others, and everything is fine. 
The power source (made by me) is 12 V and regulated with a 7912 vreg that can support max 1.5 A so I think everything is ok here.
Actually I don't know if it is really a 74HS04 or not, because the inscription in the IC is just unreadable. I will put one of these in replacement: the pinout is, in theory, the same, so I don't think it will make BOOM!
Anyway, thanks for the help. I will try to put here an image of the board, so all understand what am I talking about.
DDG_X86 😎
The power source (made by me) is 12 V and regulated with a 7912 vreg that can support max 1.5 A so I think everything is ok here.Actually I don't know if it is really a 74HS04 or not, because the inscription in the IC is just unreadable. I will put one of these in replacement: the pinout is, in theory, the same, so I don't think it will make BOOM!
Anyway, thanks for the help. I will try to put here an image of the board, so all understand what am I talking about.
DDG_X86 😎
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