Hello Larry,
What I have is a Sony KP-61XBR38 same as 53XBR35 and 46XBR35. I replaced the STK-4278L IC chips and also installed a heat sink as well as the needed heat paste. This fixed the problem but when I ran a DVD still of a checkerboard pattern to tune the convergence I can't do it in service mode like other Sony models. I started to manually adjust some of the registration pots using towels to cover the lamps starting with blue to match Green. I'm having a hell of a time doing it this way. Is this the procedure to converge this particular model? Spent about 8 hours already just trying to match vertical green to vertical blue while lying on my side going cross-eyed looking at the screen 6 inches from my face! Wish there was a way in service mode to do this with a remote. Couldn't figure it out. There is a convergence option in the menu but it is limited to very fine adjustment. Hardly useful.
Thanks for any advice.
Mark:
I have questions about your putting a HEATSINK on the ICs. I just took out the D Board last night (and started a new THREAD with pics at techlore.com).
The ICs have a plastic shell. Did you cut through this shell to affix the heatsink you reference to the underlying metal?
Btw, do you know if the paste HAS to be electrically conductive in addition to thermally conductive. I ask as I just purchased Artic SIlver Ceramique thermal adhesive - so it wouldn't accidentally electrically short anything. then I've started wondering whether its also a ground to the tray.
Jim
I attached the alluminum heat sink to the metal plate under the stk's. The heat from the chips transfer through the paste to the metal plate they lie on then the heat should travel through the plate to the attached heat sinks and be dispersed. As far as paste I just used what was available at Radio Shack. It's called thermal paste and it is white. Located near the solder, irons etc.
The heat sink is just a "L" shaped alluminum fins that attach to the metal next to the 2 STK's. Do not put anything on or near the chips. It's not like a computer ICU heat sink that lies on top of the chip. Although a computer fan mounted under there somewhere couldn't hurt. Be noisy though and you would have to find 110 voltage somewhere. Hope this clears things up.
M:
OK, I get it. Thanks. ALthough I don't know that there'd be any discernible benefit to that application.
I make take a dremel cutting disk to the plastic shell on the DEAD IC and see what's under there.
This was received from another iste:
It is likely that the IC with cold solder joints has failed however it may have taken other components with it. If so, replacing just it, or both ICs may not solve the problem and may result in their failure also. Check for other failed components in that circuit.
Thermal paste need not be electrically conductive but often is. That is the reason that there is often a mica insulator used under the paste.
Heat sinks are mechanically attached to the plastic IC case often with thermal paste in between to make a solid thermal connection. There is no metal case inside the IC and opening it will destroy it.
Yea it actually works real well. The fins get hot which is the extra heat that would still be in the stk chips.