My grinder just stopped grinding... turned it on, heard a "Chunk" sort of sound and it stopped grinding. Timer works and light comes on but no grinding. I also cannot unscrew the top portion to look and see if something is stuck inside.

Think the grinding mechanism is jammed with something. Disassemble unit and look for same.

The grinder is timing out and stops if the beans do not enter the grinder. This happens because:
1- The grinder outlet is clogged and fresh beans cannot pass through the burrs.
2- The grind setting is too fine and helping clogging in the grinding chamber or the ground coffee outlet.
3- Operator may have been using dark roast oily beans. Like it or not, the dark roast oily beans do not make stronger espresso. Please stop using such beans in fully automatic espresso machines.
4- The grinder has already made over 2000 grinds and the burrs are blunted and not grinding beans as needed.
To solve this malfunction, clean the grinder. Make sure the grinder outlet to the doser is cleaned. This outlet passage is about 2 inches or more. To clean it, lay the machine on its back (water tank side) to allow better view of cleaning the doser and the passage of coffee from the grinder to the doser. Use the link below to find instructions for cleaning the grinder and replace the burrs.
Gaggia Titanium and Plus Espresso machines parts and repairs Saeco...

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/edward_bbd2c7ff4ee1828a

Grind Adjustment Tools required: Large blade and medium Phillips head screwdrivers In order to adjust the grind, follow these steps (Refer to figure A): 1. Remove all coffee from the hopper. 2. Set selector knob to the finest setting (Espresso or Turkish) depending on the model. 3. Loosen both knob retainer screws in selector knob one turn only. 4. While pressing the bag switch, located behind the spout, press the START button so that the grinder will run during adjustment. 810 model - Press the ON or START button so that the grinder will run during adjustment. 5. With the grinder still running, turn the adjusting screw in the center of the selector knob slowly to the right until a slight clicking noise is heard. Immediately turn the adjusting screw to the left one grind setting. This is the finest grind obtainable. 6. Tighten both of the knob retainer screws. Once the ESPRESSO grind has been set (Turkish for Model 835, 875, 890), the other grind settings will automatically set correctly. 7. Press the STOP or OFF button. IMPORTANT: Always be sure the grinding burrs are not touching while the machine is running on the ESPRESSO/TURKISH setting. Otherwise serious damage to the motor may result.

Does the spindle spins when you do the grinding? If not the parts in the grinder is broken. If the spindle still spins and you get sort of wood chip grounds, the adjusting wheel has come off the grinder when you adjust the grinder too coarse.You can undo the grinder if you know how to open the machine. Go to my Odea solutions and look up step by step instruction on how to. Itis very similar.All the best.

There are 3 springs in the holes around the top neck of the machine, the top part which sits under the collar adjustment knob.

My son's machine has the same issue. If I hit the timer with a rubber mallet, it works...on occasion. Let me know if it's fixable. I don't have the right tool to take it apar. The timer seems to be the issue.

Hi
Remove bean hopper
Remove grounds hopper
Remove timer knob on the side
Turn the grinder upside down
There are 4 slits on the outside edge.
Insert a screw driver into the grove and pry gently outward with a
little downward pressure on the outside until the side slips a bit.
Repeat on all 4 slits and the shell should slide off.
There is a fuse on the side of the motor that will blow and stop the motor. It is a thermal fuse and should be replaced by a qualified tech.

Generally, coffee beans are oily and form a goo in these machines.  You may get lucky by first unplugging the machine, getting some copper wire (#14 or #12) and poking around in there to loosen the crud up.  If this doesn't work, the unit will have to be disassembled and cleaned.  Messy!

http://www.cerinicoffee.com/custompages/Tech/Grinder_Adjustments_for_Italia.pdf

Is your grinder in and the lid down? My coffee maker (grind & brew) started beeping after I cleaned it and turned the left knob clockwise with the grinder still disassembled. There's a little button that is depressed when you close the lid with the grinder in there (I'd guess it's a safety feature). I pressed down that button, and the beeping went away.