Entertainment Center: TVs, Stereos, VCRs and DVDs - fuzzy screen - hitachi 50ux7b
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pickled
03-07-02, 04:35 PM
Its a 1991 projection tv and i am getting a picture but it is fuzzy and sometimes layered. Do i need to clean the lenses or something. If i do can someone tell me how.
Smokey
03-07-02, 05:31 PM
No, I think you need to think about changing the projection tube cooling fluid. It sounds like the fluid is contaminated by bacteria and has gotten cloudy.
Here's a site that sells the fluid. You need to drain down the reservoir in the set and replace the fluid. Also, remember that the fluid is basically an anti-freeze and needs to be disposed of properly.
http://www.mgchemicals.com/products/803.html
Smokey ;)
Here's a site that sells the fluid. You need to drain down the reservoir in the set and replace the fluid. Also, remember that the fluid is basically an anti-freeze and needs to be disposed of properly.
http://www.mgchemicals.com/products/803.html
Smokey ;)
pickled
03-08-02, 12:11 PM
can you direct me on how to change the cooling for the projetion tube. Where its located and everything.
Smokey
03-08-02, 04:29 PM
Changing the fluid is rather involved and often gaskets have to be replaced on the CRT lenses. And, the fluid has to be changed on all three projection tubes when this is accomplished. If you are not familiar with the need for the fluid then it is best that you let the professionals handle this task.
I did some research on your model set and found another fix noted for this unit. This may or may not apply to your problem:
****************************************************
Problem noted:
I have a problem with a Hitachi projection TV model #50UX7B. The picture is darker than normal, with streaking trails leading off the the right of contrasty images. Also, the PIP is not working properly but I am not sure if it is related bacause the customer does not use that feature hardly ever and may have failed at a different time. The video inputs on the bad also show the same trouble on the screen, but the monitor output jack has normal video on it regardless of when the input is the tuner or the A/V inputs.
Repair Information:
Surface mount capacitors C217, C201 (both 1uf) and C001 (10uf) in the comb filter module must be replaced. The comb filter module is the metal box soldered into the signal board. (The large board on the left, when viewed from the rear. Also, there are 19 SMD capacitors that need to be replaced in the PIP module, but you may find it easier to just replace the module. Hitachi part number 2375251. It is likely you will have to do both of these repairs to restore the picture to the set.
Smokey ;)
I did some research on your model set and found another fix noted for this unit. This may or may not apply to your problem:
****************************************************
Problem noted:
I have a problem with a Hitachi projection TV model #50UX7B. The picture is darker than normal, with streaking trails leading off the the right of contrasty images. Also, the PIP is not working properly but I am not sure if it is related bacause the customer does not use that feature hardly ever and may have failed at a different time. The video inputs on the bad also show the same trouble on the screen, but the monitor output jack has normal video on it regardless of when the input is the tuner or the A/V inputs.
Repair Information:
Surface mount capacitors C217, C201 (both 1uf) and C001 (10uf) in the comb filter module must be replaced. The comb filter module is the metal box soldered into the signal board. (The large board on the left, when viewed from the rear. Also, there are 19 SMD capacitors that need to be replaced in the PIP module, but you may find it easier to just replace the module. Hitachi part number 2375251. It is likely you will have to do both of these repairs to restore the picture to the set.
Smokey ;)