Friday, June 3, 2011

Phillips magnavox?

how to change coolant fluid on a rear projection magnavox???Phillips magnavox?Oh, This is a fun job... I do it at least twice a week!!!

It is messy and time consuming and requires you to remove the tube. Usually only the blue tube needs the fluid changed as some kind of scum grows in it. it sometimes also happens to the green tube.

First step is to get to the tube usually by disassembling the back of the cabinet then the front. I can not go into details because all the different models and years have a different procedure,

Next step would be to remove the neck board and the yoke. the neck board is often glued on (Cut the glue away) although I have seen clamps and other methods used to keep it from falling off. the yoke is usually held on by a single bolt on a clamp. note its position as it must be returned exactly to the same place.

You will also have to remove the connection to the high voltage connection on the flyback transformer. this is sometimes tricky. Most cases you just pull it out - Very hard pull which cuts off the end of the wire. You will have to strip back a bit insulation to reuse the wire. The installation of this wire after your done is one of the most worrysome bits. Also the grounds around the metal parts of the tube will have to be disconnected - easy job.

Usually there are 4 screws on the top of the frame holding each tube in place. usually if everything is disconnected ok then the tubes come out quite easily at this point.

After the tube is out of the television I usually place it face down in a pan. Then I mark the tube and components down one side with a permanent marker to make sure the components are put back together the same way as it came apart.

On the back of the assembly there are 4 bolts with springs attached - Loosen up these bolts a few turns at a time to release the tube from the projection lense. Once these are removed the tube is usually stuck to the lense.

Now for the messy part. A slight whack or will usually separate the assembly. There it is in all its glory the coolant. Dump the old cooling fluid down the drain and wash everything with soap and water. I use dawn dish soap.

Keep the water out of the lens as it will make a messy fog inside. It will enter through the mechanical focus adjustment quite easily. You will need fresh supply of coolant before reassembly - several suppliers have it but MCM is the easiest place to order online. Make sure you have at least one bottle per tube before starting - some use less but it is nice to have extra.

Place the lens face down in a pan and pour the coolant up to level to the sealing gasket. place the picture tube back onto the lens - coolant will gush out and thats ok. The pan will catch it. Make sure you marks are aligned also. Place the metal clamp on top of the tube and start the bolts with the springs. tighten them down evenly - no more then a few turns on each bolt at a time.

Reverse the disassembly procedure to reassemble.



The next step will be alignment and convergence. sometimes even harder then replacement of the fluid