Optoma HD26 DLP Projector No Light/Picture Repair

This Optoma HD26 was purchased on eBay as a parts repair unit. The owner said that he had it blow a fuse after installing a cheap lamp. He replaced the fuse but it was still not lighting.

There were 3 lamp assemblies and one bare lamp. The bare lamp looked to be a new Osram where as the other two lamp assemblies were cheap replacements.

Interestingly both of the cheap replacements measured in the Megaohm range. A proper bare lamp should read infinite resistance, as the Osram did. One of the lamp assemblies had pretty cruddy wires so that might have been an issue. My theory is that one of the bad quality lamps put too much of a strain on the ballast during ignition by having too low a resistance during ignition. This overpowered the Fet and caused the fuse to fail.

The cheap lamp assemblies were later torn apart and found to have conductive cement used in their construction. That is a problem. Here is the video:    • Digital Projector Knock Off Lamp Autopsy  

To test the projector I used a known good lamp assembly and then upon repair, I re-lamped one of the cheap lamp assembly housings with the included bare Osram lamp. That worked out really well.

I found that it had a bad MOSFet (19N20) in the ballast. I replaced the pair with 52N20 fets. The part # means Amperage rating, N type, Voltage. The replacement MOSfets are rated to run higher so they will work fine in place of the old parts. They may even run a little cooler.

The fan wires had been spliced so I cleaned that up with some sealed heat shrink tubing.

Lastly I noticed it had some dust in the optics (on the DMD it seems). The cleaning video for the optics will be posted here once it is edited.

I may sell this unit. If you are looking for one, check FixitFrank on eBay, or I will post a link here. If you happen to want it, email me and we can work it out.

Here is a link to the lamp if you need one: https://www.purelandsupply.com/optoma... Use YT50 in checkout for 5% off.

Thanks for watching!

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