I have this same imac it say's in ABOUT that I have 1.83 2006 LATE, I to got the line's only 3 but more to come . I have done R/D for a year now and have talked to people who have solved their problem's with V4 ADAPTER, from realmacmods, I just bought the adapter for H/D lcd and LP171WU1 (TL)(A3) in total it cost $88.00 dollars to repair AND to the person that asked is it worth it YES, I am now upgrading CPU and a DVD RW+- and memory has been done already to 4 gig's and working like a Brand new IMAC ! It took about 30 minute's to disassemble the first time and since then it's 10 minute's to get it a part, Take the memory out fist then use a credit card to unclip the front bezel and watch for the cables, from there your inside. I did find that my Fan's were not working this is another common issue, it's in the power supply with a Bad Cap. for me it was easy but if your not good at soldering don't mess with it get someone to help you. the Cap I had but can be gotten at RShack ,
I am so Happy with the screen( if you repalce with the Apple with Apple You will get the line's again) this is why I did the adapter now I will never get lines and the H/D Gloss is great to watch video's and my Mom (90) loves it and use's everyday. I'm not saying don't use Apple par,t if you do some reading and watch Vid's at youtube it helps and be informed this is a great product and will last for years.
I had to call APPLE for some help with my A1195 17" imac and even 10-11 years later they got everything fixed up so 10+ to APPLE
I hope this will help others that are trying to fix the line issue, so take a look at realmacmods they have everything to upgrade your IMAC's,, No I don't work for them they were great to help out !