One aspect of running a CRT repair shop is having a stock of random parts salvaged from machines that are unrepairable. I have a large “graveyard” of CRT parts from mostly Sony Trinitron PVMs. Recently I traded for a rough Sony PVM 1344Q from 1992. This monitor was filthy and had a number of issues. In short, the PVM needed a replacement bezel, shell, cleaning, and numerous other parts replaced and repaired. The CRT tube was replaced with a new tube in 2001, but it was not installed properly and produced a terrible image. The deflection yoke will need to be reseated and adjusted. You can see a full inspection of this monitor here: Is this Monitor trash?! | The Sony PVM 1344Q CRT Inspection – YouTube
I searched through my “graveyard” of used Sony PVM parts and found a shell, bezel and plenty of other donor parts from a Sony PVM 1342Q that was donated after the tube and mainboards failed beyond repair. I disassembled and completely cleaned the donor bezel and monitor base. The front button board will pop out if you remove the power button and the two screws holding the board on the inside of the bezel. Then you can rebuild the front of the PVM. Depending on the model of PVM you are working on, you may need to use the button board and power button that go with your main board.
At this point I needed to completely break down the rough Sony PVM 1344Q with the good tube and working internal boards. I removed the boards, shielding, tube, button board and power button to clean, service and install into the donor bezel. After installing the button board and power button, it was time to prep the CRT tube. First, I removed the deflection yoke by loosening the screw holding the yoke in place. This screw is on a ring by the convergence rings. With the screw loosened, gently turn the yoke clockwise and counterclockwise to break it loose from the masking tape along the CRT neck. Then I removed the yoke and set it aside to prep the tube for a proper yoke seating.
Deflection yoke seating is a tricky process. Rubber wedges have to be installed on the tube to evenly space and hold the deflection yoke. There is a “sweet spot” for every deflection yoke as it sits against the back of a CRT tube. The yoke needs a couple millimeters of space between itself and the back of the tube. It also needs to be evenly aimed at the back of the tube. If the yoke tilts/leans more in any direction, you will have bad problems with geometry and color purity. You may have to adjust this once you test the monitor, but for now get it set. Replace the yoke on the CRT neck and press it evenly against the new wedge pads and tighten the screw ring.
Now the tube is ready to go into the bezel and base we have set up. The bezel needs to be faced down on a soft pad to prevent scratching. Then the tube goes in followed by the shielding plate/degaussing coil. Please watch to not pinch any cables that are in the area while installing the tube and shield. There are four Philips head screws that hold the shield against the tube inside the bezel frame. Those screws are located in each corner. Once the CRT tube and shield were in place, I installed all the other main boards including the power supply, neck board and anode cap. That way I could test the monitor and adjust the yoke to proper position using the 240p Test Suite.
After some work moving the wedges and the yoke around, I found the “sweet spot.” I used black RTV silicone to secure the wedges in the “sweet spot” and then powered the monitor off. This PVM needs to have a capacitor kit installed to help it perform better. The PVM’s boards where again removed, and I developed a capacitor kit that will help the monitor adjust to its best picture possible. I removed the old capacitors, cleaned the boards and installed the new cap kit. I also reflowed solder on the adjustment potentiometers as well as any other points I saw that may turn into cold solder joints. I have made the kit public, and it includes some tips. The kit can be found here: Sony PVM 1344Q – Geometry Capacitor Kit – Google Docs
After servicing and cleaning all the boards, I was able to reassemble everything within the PVM. Then I power tested, and screen tested the PVM. Then I let it warm up for approximately 30 minutes. With the monitor running great and warmed up, it was now safe to adjust the geometry and convergence. I adjusted the geometry using the potentiometers on the main board in the deflection adjustment block. There are also some pots that can assist you with focus and horizontal static convergence on the neck board. I used the SNES console version of the 240p Test Suite Software. For more information on the 240p test suite, check here: 240p Test Suite by Artemio (itch.io). Now this Sony PVM 1344Q has found a good home inside the parts of its salvaged 1342Q brother. It’s clean, produces a great picture and performs perfectly.
