I've got the Hong Kong 410 without the handle. I bought a belt replacement kit with 4 belts from console5. I saw a few mentions of people having issues replacing the rewind belt. I couldn't find much on it, but I was able to successfully replace the rewind belt, and it wasn't that difficult, so I figured I'd post instructions and a few pictures to help other out.
Disassemble the 410 down to the player internals. Remove the circuit board, but I'd recommend against removing the tape heads. I now need to reset the azimuth, but I guessed and it loads tapes. If you need to remove the play head, just remove the screw on the right, and slide the play head out from the spring/washer/screw on the left.
Once you get down to the mechanical portion, the main belt, and the two that drive the counter are fairly easy to switch. The rewind belt is a little more interesting.
First, rotate the left spindle, pushing on the top to give a bit of slack. Use a small flatblade screwdriver to pull the belt up. Once the belt is freed from the left spindle, it'll still seem trapped around another pulley under the center of the deck.
Now, flip over the mechanical deck. On the left, there is a white plastic nut. Use a flat blade screwdriver to rotate the nut. It should then slide up and off the spindle.
With the nut off, you should be able to slide the white arm up and off the peg. At this point, you should be able to free the white arm, which has the smaller hidden spindle. There is a red cap that makes getting the old belt out and the new belt in a little interesting, But, once the new belt is wrapped around this spindle, you should be able to reverse the instructions to re-insert the arm, feeding the belt through to the other side. After the arm is reinstalled, flip the unit over and slide the belt around the left spindle.
After I did this, my deck seems to play and rewind perfectly. I didn't realize I shouldn't mess with the azimuth screw, so even though the deck seems to load most tapes fine, I really need to get an azimuth adjustment tape to dial it in.
The best advice is to go slow and don't force anything, take pictures as you go if you don't trust your memory.