Home Theater Forum and Systems banner

1 - 11 of 11 Posts

·
Registered
Joined
·
402 Posts
Discussion Starter #1 (Edited)
Hi all,

First, let me state that I am in no way an authority where this is concerned, so maybe it's the height of stupidity that I should even try. Here's the problem: my HD picture needs a slight adjustment in vertical position (Mitsubishi WS-65511). I have made a few slight adjustments to the color decoding in the service menu before based on an owner's thread that provided the procedure for fixing the red push, but that was about as high level as you can get ("push this button, then advance the number to this using this other button, then push yet another button to save"). I also recorded the original settings just in case.

Back to my question. I obtained a service manual for this RPTV, with the hopes of finding a setting to adjust the vertical position. I believe it is the V-POS setting under the JNGL function menu, which is currently set to 31 (range 0-63). But when I change the number (with an overscan pattern from DVE displayed), the picture jumps slightly, but does not change position. What am I missing?

On a side note, the service manual provides the initial settings (factory default?) for everything. I noticed that many settings that have never been touched are currently set differently on my RPTV than in the manual, and there are even additional settings not detailed in the manual at all. Is it possible that changing any one setting affects others? What about changing settings in the user menu (brightness, contrast, etc)... can that effect the settings in the service menu? Maybe an updated version of the manual that reflects a revised firmware?

Thanx!
 

·
Plain ole user
Joined
·
11,121 Posts
The default settings are a starting point if you have to change a board or EEPROM. Your set was adjsuted at the factory and that is why it deviates from these defaults.

If you look in the R, G, & B convergence options, you will see that there are vertical height and linearity controls for each one. IIRC, you have to adjust the height there on this model.
 

·
Registered
Joined
·
402 Posts
Discussion Starter #3
The default settings are a starting point if you have to change a board or EEPROM. Your set was adjsuted at the factory and that is why it deviates from these defaults.
Thanks. That makes sense.

If you look in the R, G, & B convergence options, you will see that there are vertical height and linearity controls for each one. IIRC, you have to adjust the height there on this model.
Yea, I saw those. If I have to mess around with the individual rasters for Red, Green and Blue just to change the vertical position, I may just live with what I have (it's not too bad, but I'm picky about this stuff.... or so my wife tells me). Just knowing how to get into the service menu, let alone fiddling with things, scares me. Since it's not the vertical height I need to change, but just the vertical position, I was hoping that I could just adjust one setting real time with an overscan pattern displayed. Other settings in the same group (JNGL), such as HWID (horizontal width) have the desired effect when changing that (i.e. with each number change, the width stretches or compacts accordingly), even before saving the parameter. The V-POS is described as the vertical position in the service manual, so I thought this was what I needed. Whatever the case, for some reason adjusting it has no effect at all of the picture position (which is why I thought I might be missing something; maybe another parameter has to be set before this one takes hold?)

Thanks for the quick response! :)
 

·
Plain ole user
Joined
·
11,121 Posts
Don't be simply afraid of the service menu. As long as you don't hit ENTER to save in the service menu you can't screw it up badly. It will just go back to the last settings. This is NOT true in the convergence menus. In both, record where you start so you can get back there if you mess up.

Now with respect to position. You have to be careful here. If you adjust position in the electronic controls, you effect that change by altering the d.c. offset on the convergence yokes. Too much offset can cause the chips to run hot and fail prematurely or drift. You should always check the offset, and adjust the electronic controls to get no more than 100 mV of d.c. at the convergence outputs, then center the image with the position rings on the back of the deflection yokes.

With any controls, don't be afraid of them, just don't mess with them unless you know exactly what they do, as above.
 

·
Registered
Joined
·
402 Posts
Discussion Starter #5 (Edited)
Don't be simply afraid of the service menu. As long as you don't hit ENTER to save in the service menu you can't screw it up badly. It will just go back to the last settings. This is NOT true in the convergence menus. In both, record where you start so you can get back there if you mess up.

Now with respect to position. You have to be careful here. If you adjust position in the electronic controls, you effect that change by altering the d.c. offset on the convergence yokes. Too much offset can cause the chips to run hot and fail prematurely or drift. You should always check the offset, and adjust the electronic controls to get no more than 100 mV of d.c. at the convergence outputs, then center the image with the position rings on the back of the deflection yokes.

With any controls, don't be afraid of them, just don't mess with them unless you know exactly what they do, as above.
Thanks again, my friend. The maximum I changed the V-POS was +/- 6 from the current value of 31. I did save the value once to see if the change took hold when I exited the service menu, but then immediately changed it back to 31 when no change was apparent. Hopefully I did no damage. Since I have no means of measuring the voltage (even if I knew how), I think it wise for me to leave it up to professionals. I would just have the set ISF calibrated, but I am holding out for a digital set where the settings do not drift (from what I understand) - once calibrated, always calibrated (?).
 

·
Plain ole user
Joined
·
11,121 Posts
Most techs are not familiar with how to make these adjustments properly, and most calibration pros are not either. Most of the former just fix sets well enough to get a pix, and the latter don't understand how the circuits work well enough to get it right. You can buy a digital multimeter for $20 and measure the voltage. It is not a big deal.

While I do not generally give step by step instruction in these forums, this is a case where even the pros don't get it right, so I would rather lead you through it and make sure that it is done properly.
 

·
Registered
Joined
·
402 Posts
Discussion Starter #7
Thank you, lcaillo. After looking at the overscan pattern again, I don't think it's worth it to go to all of that trouble (only a perfectionist like me would ever notice, anyway). Add to that the fact that I am a complete novice (with a penchant for messing things up... even sure things), and I don't know that it's worth the risk. Changing a menu option is one thing (the changes I made to remove the red push and "fix" the decoder errors worked like a charm), but anything more involved just is not worth the risk (whenever I am involved, there is a risk.... trust me).

A couple of questions, if I may. Why was the vertical position (JNGL, V-POS) ineffective (well, the image did jump slightly, then remained unchanged)? Given the starting value of 31 (range 0-63), could I have done any damage by changing it +/- 6? If so, how would I tell?

On the bright side (pun intended), I just finished re-calibrating both the brightness and color levels via HD-DVE (I'm stoked... both the red and blue are spot-on, and the green is really close), and though the Mitsu is not great at holding black levels (when comparing the "PLUGE" and "PLUGE with white bar", it's not bad (I took a happy medium between the two). One very happy camper here...:)
 

·
Banned
Joined
·
3,807 Posts
I know you've already said that you're aware of this, but just to drive it home: Write all the original settings down and store them in a safe place. I read a lot of sad stories in a Tosh RPTV thread I monitor about folks who screw up their sets royally and then don't remember the original values.
 

·
Registered
Joined
·
402 Posts
Discussion Starter #9
I know you've already said that you're aware of this, but just to drive it home: Write all the original settings down and store them in a safe place. I read a lot of sad stories in a Tosh RPTV thread I monitor about folks who screw up their sets royally and then don't remember the original values.
Thanks, eugovector! All of the settings I have changed I have recorded the original values in a text file along with all of my other A/V settings like AVR channel trim (and it is backed up weekly).
 

·
Plain ole user
Joined
·
11,121 Posts
Thanks, Marshall. This point cannot be overstated. In the Mits SM it is a little harder to do permanent damage than some (some settings can actually do permanent hardware damage in some brands and models), but the best proactice is simply to not adjust anything unless you are sure of what it does and understand the possible outcomes. If you tinker, you can get into trouble. Regardless of how sure you are, recording the original settings is ALWAYS a good idea.
 

·
Registered
Joined
·
402 Posts
Discussion Starter #11
Well, I seem to have answered at least part of my question. I was digging some old stuff up on a Mitsubishi RPTV enthusiast forum, and found that certain Mitsu RPTV chassis, including V21, disables the JNGL VPOS control altogether. In order to effect a vertical shift, the individual R, G, and B convergence options must be changed (as surmised by lcaillo). Further, another poster claimed that the only control that needed alteration is the green, and the red and blue convergence will follow (in a course sense; a full convergence check and re-adjustment should follow). Since that is a little farther than I am prepared to go, I guess this marks the end of "Derek's Adventures in the Service Menu". At least I know that all my changes to VPOS to assess a difference did exactly...... nothing. Thanx, all for your help!
 
1 - 11 of 11 Posts
Top