Yesterday,My dreamcast suddenly cannot recognize any GD or CD-R media..(It spinned up and checked any media but it only stayed at the start menu.. won't start any dreamcast game or application)
I measured resistance value of Laser Lens by putting multimeter's red probe and black probe on 1 and 2 pin of ribbon cable connector which located on the back of Gd-Rom pickup's PCB. and to my surprise, It measured more than 1M ohm..
I fiddle with small pot of Laser Lens..But measured resistance value won't drop to less than 300k ohm..
I noticed that It has something wrong with Laser Lens or flat cable,So I put multimeter's red probe and black probe on each end of flat cable,and I finally found that 1 pin of flat cable have been break..
I took advantage of broken DVD-RW which has wide and strong flat cable and I cut this strong flat cable into almost same width(16 pin) and height with Gd-Rom's flat cable as possible as I can..
and scratched one end of strong flat ribbon cable with knife in order to expose all 16 pin of metallic conductors .
then,I strip off blue stiffener from cut off strong ribbon cable and insert this blue stiffener together with one end of strong flat ribbon cable..
It is somewhat hard to insert one end of strong flat ribbon cable and blue stiffener together into connector of Laser Lens. But without blue stiffener, It is impossible to steady strong flat ribbon cable in connector of Laser Lens..
Now,My dreamcast really works very well to read any CD-R or GD media like before..
I think that If Your Gd-Rom's flat cable is broken and has CD-RW or DVD-RW which have wide flat ribbon cable then you don't have to purchase any dreamcast's ribbon cable of below ebay link..
https://www.ebay.com/itm/280801156507