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Mits VS60601 convergence

J

JURB6006

Jan 1, 1970
0
Hi all, me again;

Here again we have a case where something is acting more strangely than
expected. Set came in bowed top and bottom and vertical lines at the sides were
way off. Ed went ahead and threw in a set of output ICs to no avail. He's
checking the waveforms to the convergence module and the only thing that seemed
strange was the H parabola waveform. Although the DC level was OK, the bottom
was clipped off.

It was then delegated to the dog department (me). Further investigation showed
that the H parabola is not an input, it's an output. After checking as well as
I can I decided to order a waveform IC for it and found it to be NLA, but the
whole module was about $100 so we ordered that. It arrives and as near as I can
tell there is no change. The parabola is now soft clipped, but still not what I
consider right. I got into the convergence setting mode and all controls that
are pertinent to the error work fine. The service mode static proves that the
output ICs are not clipping, the rasters move evenly throughout the screen. You
can't tell this in the customer convergence mode as all you get are the
crosshairs.

It's already been determined that this is not a complete lack of convergence,
top and bottom H lines are converged at the center of the screen. This points
me back to the H parabola, however, as I'm screwing with the controls to see
what's dead and what's alive the set shuts off. I didn't really want to save
changes at this point anyway, but the plot sure thickened. I decided to go to
my other bench and let the thing play undisturbed for a while, come back and go
into the convergence setting mode and it turns of again. This took about
(possibly exactly) the same amount of time to occur as if the sleep timer had
been activated, but does not occur if you just leave it alone.

There is one other thing about this set, it's dark. I've been in the service
menu and the sub pix is working, and video level. The menu is also dark. At
this point I'm starting to think EPROM, but the OSD is displaying the value
from the EPROM right? The value is there, correct and has the proper effect
when adjusted, but it's as if the range is insufficient. Now am I looking at
the micro ?

I don't have a print for the 60601, but the VS XX43,44,45 series uses the same
chipset for the convergence and that is what I'm using. The problem is that
there are two EPROMs and I don't know which one stores the convergence data. I
was also wondering if they come partially preloaded, because I think those DA
values are cabinet/model specific. Looks like your basic run of the mill EPROM,
but if I get one I want it from Mits for that set of course.

Thanx in advance for any help. See the PS below.

JURB

PS: I always try to remember to give TIA because I post this stuff at home and
my ID and stuff is not setup on the shop's PC. I read the replies through
Google and can't post from there. Sometimes I forget, so don't ever think I
don't appreciate your time here. Especially since some of my posts have to do
with TVs from hell.

JURB
 
T

TV Fixer1

Jan 1, 1970
0
Jurb, I've run into a couple of these; is it possible to get convergence, or
will the adjustments not make it? Both I saw had bad EEPROMS; they do NOT come
preloaded from Mitsubishi. Both would converge (took about an hour), but would
lose settings a short time later.
 
L

Leonard G. Caillouet

Jan 1, 1970
0
This is a VZ4 chassis. Not uncommon to find a few bad caps. Most problems
have been related to that.

The EEPROMs are blank from Mits as far as I know. They both have the same
part number 274P333010 (24c04*P). Not sure what the * means. Maybe they do
preload something in them...

IC701 is the convergence eeprom, but I have never had to change one.

From Mits re misconvergence:

1. CHECK FOR -8 VDC TO THE CONVERGENCE PCB AT "VM" CONNECTOR PIN 3, IF LOW,
MISSING OR NOISY, CHECK C936 (1000 UFD 16 V) AND C935 (100 UFD 16 V) ON THE
MAIN PCB. 2. CHECK C924 (1000 UFD 36V) AND C925 (100 UFD 50 V) IN THE -24
VOLT SUPPLY CIRCUIT ON THE MAIN PCB. 3. GO TO THE CONVERGENCE MENU (MENU 2 3
5 9) AND CHECK THE ADJUSTMENT SETTINGS FOR CONVERGENCE. IF ALL ITEMS ARE SET
AT "127". THE EEPROM SETTINGS ARE AT DEFAULT. CLEAR THE CONVERGENCE MENU AND
ACCESS THE OPTION MENU (MENU 1 3 7 0) USE THE ADJUST BUTTON TO SELECT
E2RESET AND PRESS QV. THIS SHOULD INSURE THE EEPROM IS CLEAR. AT THIS TIME
ALL ADJUSTMENTS, CONVERGENCE GEOMETRY AND CONVERGENCE SHOULD BE DONE. 4.
CHECK FOR 20 VPP VERTICAL PULSE TO PIN 9 OF THE "VJ" CONNECTOR TO THE
CONVERGENCE PCB, IF MISSING, WEAK OR DISTORTED, CHECK PULSE AT SOURCE PIN 7
OF IC401 (PUMP UP OUTPUT) ON THE MAIN PCB, IF THE PULSE IS NOT CORRECT AT
PIN 7 CHECK C402 100 UFD 50V AND IC401 PART # 270P064020. 5. Z905 IS OPEN.
CHECK FOR LEAKY D913 PART # 264P722010, OFF OF PIN 12 OF T900 (15-VOLT LINE)
ON THE MAIN PCB.

Leonard Caillouet
 
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