MItsubishi VS60609 No convergence correction

[Leonard Caillouet]

Are all of the clock and data lines clean on al the busses? Do all of the
functions work other than convergence? Have you looked for coolant on the
boards very very carefully?

Leonard

 

[Alan Harriman]

Hi all,

I'm hoping someone has seen this.

Mitsubishi 60" Projection
Model: VS60609
Chassis: VZ9+
Cust complaint: Check over, pix distorted & curved

This set has a uniformly bowed pix on all four sides, the customer
convergence adjust has no effect and the convergence amp (STK393-110)
stays stone cold. Replaced amp and confirmed plus and minus 24v, but
with no change. Also, the plus and minus 9V, the 5V, and 3.3V to the
convergence generator and op-amps check good.

After further testing, it was discovered that the main system micro is
sending a convergence mute (C_mute) signal to the convergence
generator and convergence amp IC's. Apparently, the convergence
correction is muted during power up and when switching input sources.

I injected a DC power source in place of the C_mute output pin of the
micro. As I slowly increased the voltage, a threshold was reached
where the mute lines went high and convergence returned to normal. I
could easily toggle the voltage back and forth and watch the
convergence pop in and out. For some reason the micro is holding the
voltage low. The microprocessor (100 pin flat pack) and eeprom was
replaced, still with no change. At this point, I'm kinda running out
of ideas. Anyone seen this?

Thanks,
Alan Harriman

 

[Alan Harriman]

Are all of the clock and data lines clean on al the busses? Do all of the
functions work other than convergence? Have you looked for coolant on the
boards very very carefully?

Thanks for the reply. I've checked the convergence, main and tuner
clock and data lines and they all look good at approx 5VPP. The other
non convergence functions appear to work fine, ie Circuit Adjustment
Mode items such as vert height, etc.

I looked for coolant leakage, but did not see any. I'll look again
perhaps more carefully. I'm almost tempted to put about a 4.7K pull up
resistor from the C_mute line to a 5v source <g> Anyone have the tech
support line for non-ASC servicers?

Alan

 

[[email protected]]

The system control is likely missing something it needs to see before
it will turn on the convergence. Check all the inputs to the system
control and the clock and data lines.