Sony VPH-G70 Convergence problem???

[countryhick]

I have taken 2 pictures of the screen (projector has not yet been correctly setup). Pic 1 was taken just after turn on, Pic 2 was taken 30mins later.
What do you guys think? Does it look like replacing the convergence IC's will cure my problem?

Regards Andrew

[lcaillo]

Could be a bad solder connection from what you show here. Can you adjust it after warm-up?

[countryhick]

lcaillo wrote:

Could be a bad solder connection from what you show here. Can you adjust it after warm-up?

Yes, I can adjust it after warm-up, but it will drift and change its position just about every time I turn the unit on. I did pull out the "DC" (convergence board) and re solder lots of joints even though they appeared to look fine. Any ideas would be greatly appreciated.

Cheers Andrew

[lcaillo]

If you can adjust it the output stage is likely OK. More likely you have a bad related part such as a cap of op amp in the convergence generator causing drift. It would take some troubleshooting to know.

[countryhick]

Lcaillo, I just re tested the unit to double check I could adjust the cent centering of the red gun. I can adjust it up and down but not left or right. Sorry about the miss information.

[lcaillo]

If you cannot adjust it the most likely problem is a bad output.

[countryhick]

Thank-you. I have read your convergence repair thread and would like to know if the STK392-220's have a super-seeded IC?

[lcaillo]

Not that I am aware of. I would ask about this set on the CRT forum at AVS where you are likely to find people with more experience with it. I never see these, so I can only be of generic assistance with it.

[Krankshaft]

Also don't forget to check the metal film resistors around the convergence ICs since in some cases a bad output can take one of these down with it as well.

If an upgrade doesn't exist now for your STK it probably never will since Sanyo discontinued these ICs in 06.

There are more than enough in the supply chain for years to come though.

Due to lack of demend due to the price drop of DLP, LCD and Plasmas on the market which can't hold a candle to CRT in terms of contrast ratio.

[countryhick]

OK. I have replaced the convergence IC's (from B&D ENTERPRISES) I also checked all the resistors with a DMM and cross checked them with the schematics I have for the projector. I'm still faced with the same problem. With all adjustments reset, the red beam is still playing up. I can adjust the red beam up and down but not left or right.
I'm still keen to pursue the problem so if anyone has suggestions please post them.

Cheers Andrew

[lcaillo]

My guess would be that you missed something. Could be in the convergence generator as well...time to get out a scope and check the signals from the CG to the ICs.