How do I replace the blue color tube

Your blue picture tube is failing. Invest in a new TV. "If" you can find a new set of tubes(you have to replace all 3 red blue and green) they are around $800-1000. Not cost effective. Run the TV into the ground if you want to wait but do not invest any repair money in my opinion.

They must have meant picture tube, a rear projection set has three picture tubes. One red, green and blue. One tube cost probably $150 - $250 and are not that hard to change but doing the necessary convergence adjustments can be difficult especially if you have not done them before. One thing that always makes it a difficult decision is when you put one new tube in will the other two still be in good enough condition to get a good color balance.

Sounds like you need to do a color convergence. If you still have the owner's manual, it will give great detail on how to do this. The convergence menu is accessed from the video menu on the tv.
The tv has three color picture tubes, red, blue and green. The convergence alignment adjust each tube so that color from each tube overlaps each over to create a white image on the screen. Most tv's only allow you to adjust the blue and red colors.
Convergence should be performed each time the tv is moved and at least once annually.

Five blinks is the error code for an AKB (auto kine bias) error. What this means is that the set isn't able to balance the three color guns (red, green and blue) of the picture tube properly, and it's blanking out the screen.

To get the proper colors, the signals for the three colors need to be balanced, and Sony sets have circuitry to do this automatically. Other brands don't, and when they go out of balance you see a picture that starts to show tinting or colors that are off. As the picture tube ages, it gets harder to adjust the balance until finally the AKB circuit can't anymore, and poof, the picture goes away. With a 17-year-old tube, it's not surprising.

There isn't anything that can be done to fix the picture tube, it would need to be replaced. But the cost of the tube and the work required to get it set up after installation makes it completely uneconomical to repair this TV. A new picture tube is nearly $200. Then special tools are required to set the tube up (a process called convergence), so you'd need to find someone to put it in, and possibly pay to have the old one disposed of. A new 32-inch LCD set is around $350 now. Treat yourself to a new one.

To get the right colors, especially a plain white, requires the right mix of red, green and blue from the picture tube. Sony TV sets have a circuit called AKB that automatically keeps the picture tube balanced by adjusting the signals to it. If that balance can't be achieved it shuts off the picture. This may due to tube aging so one of the color guns is too weak to adjust, or failure of parts in the AKB circuit itself. If the sound stays on and the power light starts blinking when the picture goes off, this is likely why.

On the other hand, if the set is turning off completely with no picture, sound or power light, the set may have power supply problems or defective parts in the picture tube high voltage circuits.

Since there are several possible causes, this set needs to be checked by a technician who can diagnose the problem and decide what needs to be done. It's not a simple thing I can point to and say "change this part". If the picture tube is the cause, it's better to replace the set. Otherwise get an estimate, then decide whether to fix or replace.

Hello: Seems like you have a picture tube problem. The yellow color is from a weak green crt. I suggest replacing the Red and Green Crt's in this model. They are nortoriuos for Failure especially the Red. The cost for these tube vary from 110.00ea to 150.00each. I don't know if you want to spend that type of money on this set, as i Know this peticular set has an expectional picture quailty, my experience with replacing sony picture tubes, is to replace all three tubes, as the new ones will show brighter. So replacing the red and green crt's and not the blue is not recommened. But thats up to you, you might not notice the color difference yourself. You also have the option of sending the Crt's for refurbished ones or having the originals rebuilt by a company in Calif, called VDC, Video display Corp. They sell and refurbish sony CRTs. This route is much cheaper, the only problem is having the crt's taken out and sent for repair. The other option is to think about purchasing a new set. As this repair price could reach into hundreds of dollars, Around $600 to $700 for parts and Labor..

THIS TV HAS KNOWN PROBLEMS WITH PICTURE TUBE FAILURES AND I WILL PREDICT THAT AT SOME TIME IN THE FUTURE EVEN IF YOU GET IT REPAIRED NOW, ONE OF THE REMAINING TUBES WILL START GIVING YOU PROBLEMS. YOU HAVE THREE TUBES IN THIS UNIT (RED,GREEN & BLUE) AND THE RED TUBE IS DEFECTIVE. SORRY FOR THE NEWS BUT JUST TRYING TO SAVE YOU THE ULTIMATE COST FOR REPAIRS, FOR A PICTURE TUBE REPLACEMENT AND SUBSEQUENT SET UP IS A MAJOR & COSTLY REPAIR.
HOPE THIS HELPS

Three guns Red Blue and Green in the picture tube of an old CRT set. If one of the guns goes out it effects that color. Sounds like one of the guns inside of the tube is going out, To costly to replace for such an old antilog set that will have to have a convertor box next month anyway.

no not worth repair.

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