Cartridge carriage is not lowering enough and that is causing the issue. You can adjust the lowering level with the screw on top. In my case cartridge was not properly installed and spacer under cartridge was missing. Without spacer cartridge was too high. Even with the carriage lowered to the max lead out groove detection was not working, exactly the same as on your turntable. Once I installed spacer (in my case 2mm), and adjusted carriage height issue was fixed. I hope this helps.
That's a very nice turntable .I own the Garrard 990b .Make sure too oil the motor it will affect the speed not being propley oiled . The idler wheel is the same as the original one from 990b You have too also check the dried up grease under the changer too . These are great sounding turntables . I bought a Audio Technica cartridge from eBay missing the stylus . I have a precept 440 and that's a great sounding cartridge too . But I have a cheaper audio Technica cartridge the green one .49.99 But the Audio Technica Precept 440 was a very expensive cartridge
Have you tried a VERY light sanding of the edge of the idler-wheel - this can sometimes fix the problem. I have done this on many of my own Garrards... A suggestion !
