Panasonic PT56wx51c (focus and cleaning)

[Bent]

I have a 51 series wide screen CRT type RPTV, it's overscan is a bit high, it's focus is a bit off, and it's convergence is slightly less than perfect.

I've read of the service mode convergence access codes, I've even entered the service mode once.... but lost my nerve prior to changing anything.

How difficult is a service mode convergence routine on this set, how long will it typically take, and how likely is it that I may screw up to the point of not being able to return to where I was? (I'm not interested in doing any colorometry work, as I don't have the measurement equipment, but I'd like to get better focus and convergence.
Can I perform mechanical focus with a picture (grid?) being displayed, and while I'm in there, would it benifit from a cleaning (lenses and 1st surface mirror?, - it's never been opened in 6 years.

[Krankshaft]

Focus is typically adjusted in one of two ways electrostatic focus (on the HV block) and mechanical focus.

Focus usually doesn't need to be touched unless components have aged causing the focus voltage to drop.

Focusing the red and green is no problem however focusing the blue is a compromise between blooming and defocusing so your better off not messing with the focus unless you either remove the tubes or replace the flyback or HV block.

As for an optics cleaning that is something that you can do and can improve picture quality greatly if there is alot of dust on the optics.

I just did my 2003 Toshiba after a convergence amp replacement. There was plenty of dust in there.

Loosen all of the screws holding the screen bezel in place and remove it carefully noting any connectors that need to be disconnected.

Then loosen the screws securing the 3 lenses to the tubes (don't mix them up).

Then using a dry microfiber cloth wipe the top and bottom of the lens and don't forget to wipe the glass directly underneth the lens where it was mounted.

Don't forget to clean the rear of the screen too.

The microfiber did a good job of dusting without any liquid but if you must using something use rubbing alcohol or camera lens cleaner. Be careful since the projection lenses are plastic.

Whatever you do DO NOT loosen any bolts with springs on them those seal in the coolant.

As for convergence most TVs have a built in crosshatch pattern in service mode.

Turn off the red and blue tubes leaving the green grid showing.

Then using a convergence grid available from the manufacturer align the green tube crosshatch to the grid. Then align the red and blue to the green. You can eyeball it but don't expect a perfect conergence without a grid.

After the congergence is to your liking its time to save the settings to touchfocus or magicfocus or whatever your TV has to record the convergence settings. To do this you normally hit a number on the remote then hit the touchfocus button and the convergence settings are saved in memory.

As for the specific steps to call up service mode and such they vary I would recommend getting a service manual for your set they explain how to get into service mode and how to manipulate the points.

[lcaillo]

Thanks for your contributions, krankshaft. I cannot always respond in as timely a manner nor with as much detail as I would like.

One note about focus. It is often never right from the factory, so it is worth checking and adjusting anyway. Also, on cleaning, I have been experimenting since my old favorite cleaner is NLA. The best I have found, and tested to be safe on everything that I have found, is a mix of 3-5% each Kodak PhotoFlo and Isopropanol, in distilled water. I have tested on various optics, RPTV screens and mirrors, touch screens, LCD, PDP, anti-glare coatings, coated lenses, mylar and first surface glass mirrors and found it to be perfectly safe and a very effective cleaner with no residue. I will be making a post with the results with and without the alcohol and comparing to another cleaner when I complete the testing on the latter.

[Bent]

I have a copy of the service manual, there used to be a site called pannytv.org that had lots of info on the PTxxWXxx series RPTV's.

I find the notes on the convergence methods to be kinda unclear - leading to my trepidation. is it necessary to use a template for convergence, or can I use a DVD as my source material? Also, can I do the mechanical focus with the tv energized?

[Krankshaft]

Bent wrote:

I find the notes on the convergence methods to be kinda unclear - leading to my trepidation. is it necessary to use a template for convergence, or can I use a DVD as my source material? Also, can I do the mechanical focus with the tv energized?

Most TVs when in convergence mode bring up a crosshatch pattern by which you then adjust certain points where the lines intersect horizontally then vertically.

Using a DVD wouldn't really help since the TV generates its own crosshatch pattern to adjust and doesn't display any video other then the grid.

As for adjusting the electrostatic focus yes it can only be done with the TV on.

Each color is adjusted by calling up the grid in question in service mode then adjusting the focus pot for the finest sharpest line. On the HV block you will notice 2 rows of pots one marked F for focus and one marked S for screen.

Leave the screen pots alone the 2 rows of pots will also be labelled R, G, & B for red, green, and blue.

Also another focus point is on the CRT lenses if you loosen the wingnut you can turn the lenses clockwise and counter clockwise. You adjust these by looking into the lens with the TV on and adjusting for the sharpest picture.

Like I said the red and green will be easy but the blue will be a compromise.

[Bent]

I'm aware of blue being the trickiest. If I were more up to speed on this stuff, I'd jump right in...
I have seen pictures of the six trim pots you mentioned, and I understand that if I accidently touch and inadvertantly adjust 1 of the three screen pots I'll throw the colorometry out the window for good till I can get a calibrator in....

You said focus by looking into the lens? (don't you mean by looking into the screen stack?).

[lcaillo]

Actually, the screen controls are something that most calibrators don't want to touch. They are not used for colorimetry and sets vary greatly in the proceedure for adjusting them. One should always refer to the service literature for the procedure. Some sets are very critical, others are not. ]

For electrostatic or electromagnetic focus you can look directly into the lens on the CRT. YOu can also do it on the screen. Blue is only tricky because it is not going to focus as well. Just adjust it for the best focus possible. Ignore recommendations to defocus blue.