Chaos Ray Tube

Phase Tuning

about repair calibration modding

Repair Log

Commodore 1701

Issue: image shifted on the left

Resolution: In the manual it is mentionned: C507: “open/short: image shift to the left”. Replacing C507 resolved the issue.

Sony PVM-9020ME

Issue: image is only in black and white

Resolution: caused by 2 trimming capacitors CV101 and CV102 on the signal board. Try to adjust caps or replace them if out of spec.

Sony PVM-14M2E

Issue: Does not power on anymore (green led stays off)

Resolution:

It seems this model is prone to have failure of the HOT (horizontal output transistor. When this one gets shorted, it might cause failure of some IC on the power suply board.

Replaced fuse, IC601, IC602 on the power supply board. Replaced Horizontal Output Transistor Q501 that had a short on the main board.

More details in this article.

Sony PVM-9040

Issue: Does not power on anymore (power LED quickly on then off)

Resolution: Issue was on the power supply board. Capacitor C612 47uf 50V was bad. Replacing it resolved the issue

Sony PVM-9220ME

Issue: Does not power on anymore (power LED quickly on then off)

Resolution: Flyback transformer to be replaced

Philips CM-8802

Issue: visible horizontal lines and image too bright

Resolution: Adjusted SCREEN to lower G2 voltage

Sony PVM-1443MD

Issue: only horizontal line is displayed

Resolution: IC501 was not getting 12v vvc then further investigation revealed that IC505 in the 12v regulation circuit had bad joints

JVC TM-A101G

Issue: vertical foldover

Resolution: measured voltage at IC421 (vertical output IC), noticed incorrect voltage (0.9v instead of 1.9) at pin 7. Checked capacitor next to it (C454). Capacitor measured 33UF instead of 100UF even if visually it looked OK. Replacing the capacitor fixed the issue.

Sony PVM-2130QM

Issue Electric arcs / sparks at the back of the monitor

Resolution : Having sparks inside is a sign there is a HV leakage. This model has a HVR (High Voltage Resistor). That HVR had tiny cracks (really hard to see) that were letting HV escape. Unfortunately replacement for this part is hard to get. Adding a layer of high temperature silicone on the area that had the cracked allowed to keep HV inside and fix the issue.

A similar issue was reported here

Issue Picture is OK in 50Hz (PAL) but it vertically squashed in 60Hz (NTSC)

Resolution

On the D board (deflection board), there is an IC responsible to switch between 50/60 Hz (IC1512). Next to it, on the traces side of the PCB at the location of R1529 there is a small diode on a thermal pad. Usually the solder points of the diode deteriorate at this location. Removing the thermal pad, reflowing the solder of the diode and placing new thermal pad solved the issue. This issue seems to be a common issue, I have seen it on at least 3 PVM-2130.

Sony PVM-1454QM

Issue High voltage is present but the screen remains dark.

resolution Increasing the SCREEN has no effect on the screen, it does not get brighter. Looking the CRT neck, there is no orange glow. This indicate that the filament are not glowing. Checking the voltage on the CRT neck board for the filament (AC voltage) indicated 0 volt. Looking at the flyback solder points shown some cold solder joints. Reflowing the points with fresh solder fixed the issue.