JVC AV-32S575 - linearity and other questions - AVS Forum
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post #1 of 5 Old 04-27-2013, 12:14 AM - Thread Starter
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Hello everyone,

I just recently purchased the JVC AV-32S575 for use in an arcade/MAME setup. It seemed ideal with it's HDMI port and 480p support. Now for the issues..

1. What I've found to be called "edge linearity" may be one of my issues. The image seems to compress on the right hand side and it is very noticeable with scrolling 2D games. Drawing a grid pattern (from an arcade ROM - most had service modes) the boxes to the right 15%-20% of the screen are visibly compressed.

2. The screen seems to be rotated (just slightly) beyond what the menu tilt correction can solve.

3. The brightness of the screen seems to distort the image on screen, "blowing out" edges and distorting geometry.

I have a copy of the service manual for this set, entered the service menu and tried my best (recording original values) to adjust this set to suit my needs. There are no explanations of these settings in the documentation, but at least most are self explanatory.

[in service menu]
Code:
DEFLECTION:
D01 V.SIZE
D02 EW
D03 H.SIZE 
D04 V.SCORE
D05 V.LINE
D06 V.CENT
D07 EW.TRAP
D08 BOT.CORN
D09 TOP.CORN
D10 V EHT
D11 H EHT
D14 H.CENTER
D15 H.FREQ

What do EW, V.SCORE, V/H EHT, V.LINE do? And what about H.FREQ? All it says is "Adjust the < D15 >(H. FREQ.) so that an optimum
horizontal synchronization is obtained."

Any suggestions? New to the forum, go easy please. smile.gif
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post #2 of 5 Old 04-28-2013, 10:15 AM
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1. There's probably not a service menu adjustment to fix a geometry issue on just the right side of the screen: most adjustments will affect the top and bottom or right and left sides of the screen at the same time. It doesn't look like you have any adjustment that may reduce this from the list you provided. Somebody else may be able to speak on this.

2. Tilt is affected by the direction the crt is facing: north, south, east, or west. If there is no tilt adjustment in the service menu, try orienting your set in a different direction.

3. This is called blooming and is normal for a crt. This is why 10-20% of the picture on the screen is cutoff (so that consumers won't notice it). You can reduce the amount of blooming by lowering the contrast (contrast should be below 50% anyway) and properly calibrating the brightness.

Referring to the service menu adjustments your listed: v.line is probably "vertical linearity" which compresses and expands the top and bottom of the screen. I don't really know how what the other values do or how to properly adjust them.

Also, on many crts, the geometry adjusts quite a bit after the set has been warmed up for about 20 to 30 minutes after being turned on.

Hope this helped.
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post #3 of 5 Old 04-28-2013, 10:38 AM
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I've seen blooming worse on cheaper CRTs and really bad on ones that have developed circuit problems. I read somewhere that better sets have improved power supply/HV transformer design to reduce it dramatically. Yeah reducing contrast helps a lot.

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post #4 of 5 Old 04-30-2013, 04:31 PM - Thread Starter
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Yeah the blooming on this set is pretty dramatic. With a PC input the taskbar will disappear with a bright white background. If adjusted to a bright scene, a dark scene will pull the taskbar up about an inch leaving a black gap.

I've also read that this is due to poor voltage regulation. May just be some damaged or cheap regulators or an issue with the power supply coming from the mains.

The tube and boards are out of the chassis right now and going into the arcade chassis soon. I can take voltage measurements once that step is done.
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post #5 of 5 Old 05-10-2013, 09:20 AM - Thread Starter
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Well this is interesting!

I was trying to adjust my deflection coils to correct the tilt (set orientation didn't fix it, I've tried it facing all polar directions - degaussing cycles didn't help either) but they don't seem to budge, even after releasing the clamp. Possibly bonded with glue to the CRT neck. When all of a sudden my picture goes BLANK.

Immediately I begin to freak out, thinking somehow I broke my set. After some reading and checking around I discovered the awesome little feature they put on the HDMI board for this set (and for sure, many others). The optical sensor which locks the HDMI board if it detects a light source. I was using a flashlight at the time...rolleyes.gif

Now I've gone and done the song 'n dance routine trying to reset the thing but I still can't get it to work. Here's where I am at:
Quote:
Self-Check:
With factory remote set to TV and VCR...
Set SLEEP TIMER to 30 MIN
With SLEEP TIMER still on OSD - on remote press DISPLAY and VIDEO STATUS
This will bring up the test mode screen with the onboard diagnostics: SELF-CHK. Press 4 on the remote to perform self-test.

There are two possible states for a system on this set, OK and NG (abnormal.) My set displays NG9 for HDMI. The onboard diagnostic EEPROM can store upto 9 errors per device.

Now according to the service manual, pulling the power from the wall at this screen will SAVE any errors and powering down with the POWER button on the remote will erase all the errors. One source I've read states that erasing the errors will reset the HDMI board.

Nope.

OK, method 2:
From the service manual:

(wish I would have paid more attention to this before-hand!)

What I read says to power down without fault (using power button) then unplug the set. Short pins 1 and 2 with a jumper then plug in and power on the set. The HDMI source should be on at this time, hooked up to the set and should display the image. Unplug the set immediately and remove the jumper. Set should function as normal now.

Nope.

My next try will be to go through the HDMI options in the service menu.. they're all unlabled and the service manual says not to change any values. But also includes the default values. Maybe the intrusion sensor changed a hard value which can be set back..

Also worth noting, very interesting... it seems that this HDMI board is nothing more than a HDMI to YPbPr converter. The outputs tie right into the component video chip. Furthermore I discovered this while scanning the schematics:

Seems to be a D-SUB 15-pin connector which is not even on the board/chassis. Looks a heck of a lot like VGA to me:


I wonder if the "chip" can accept the RGB input or even accept the 31.47kHz H.Sync frequency and reproduce an image worth using. If so I might just ditch this HDMI business altogether.

--EDIT--
Solved!

I used method 2 with a little modification.

  1. Power down without fault via power button on set
  2. Unplug HDMI source
  3. Unplug AC power
  4. Jump pin 1-2 on HDMI board
  5. Plug in AC power
  6. Power on via power button on set
  7. Unplug AC power WHILE ON
  8. Remove jumper
  9. Plug in AC and HDMI source.
  10. Power on.
  11. Viola! Picture again.
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