There are several past AK threads about this too. Use the search funtion and search for something like 'dual motor lube.' The procedure is much the same for several dual idler models.
When I got my used Dual 1229, I managed to get most of the functions working correctly after very gradually cleaning and relubing the various machinery underneath. I had to keep the pitch control turned far past the middle to get correct speed, but still I could get correct speed at all 3 speed settings. The main issue was that every time I played records, after 1 to 3 Lp sides, the turntable would start chirping like a nestful of baby sparrows! I thought I was going to have to replace the motor, and even started to search for replacements online. Luckily, I learned how to take the motor apart, clean the bearings, and relube them. The motor quieted down completely, and came back strong. It's probably good for another 30 years now. The hardest part of the clean and lube process for me was getting the motor covers to begin to slide apart. After that the process went smoothly and was very successful.