I used to work in the AV support department for a large university where we maintained about a hundred projectors in-house. Here is how we approached your kind of problem:
- Most likely cause is high temp caused by lack of air flow, try these:
- Clean air filter and/or louvers, both intake and exhaust
- Make sure air intake and exhaust louvers are not blocked by external objects when in use - that can raise temp to point of shut-off
- Next most likely causes: bad fan motor or a failed sensor.
- Bad fan motor - fans can bog down if the bearings go bad; you may notice an unusual noise, typically a whining sound.
- Failed sensor There are two types: temperature and airflow.
- To fix either of these, or anything else, requires opening the projector.
- Unless you are a qualified electronic service technician (preferably with service manual and access to OEM replacement parts), this is a job for the authorized service center. Not only can you ruin the projector, you also risk fire, exploding projector lamp, and electrocution, as well as other hazards to life, limb, and property.
- Is the unit still under warranty? Many projectors are covered for three years. If you bought it with a credit card with free extended warranty (comes with most gold level cards), you should have an additional year through the credit card company.
- Unlikely, but possible causes: loose connector, bad solder joint, defective circuit component(s), etc. As above, diagnosing and repairing is a job for the service center.
Good luck! Please let me know if this was helpful in fixing the problem, or knowing when to send our for repair, or saving money. Thanks!