DVD Player Mitsubishi BD48DVD Service Documentation / Circuit Diagrams

Hi All.

My Dad has a Mitsubishi BD48DVD DVD player that is not working.

When a DVD is inserted it may function for a few seconds to a few minutes before it re-starts the DVD play. It will re-start the DVD over and over. Then it will switch itself off. Naturally, I have tried various DVDs. The video output from the player will operate for the aforementioned period of time and then freeze. It may then either jump forward by several seconds to several minutes and continue for a brief time and then re-start or it may re-start after the first 'freeze'. It can also, sometimes, take a long, long time to load the DVD after insertion.

I took the covers off to (1) Clean the laser lens (2) Take a look at the mechanical operation of the DVD section of the device

Cleaning made no difference.

The disk spins-up fine and continues spinning during the fault condition. Before a DVD was inserted, I moved the lens towards the outside of the DVD area and this returned home without any apparent difficulty when a DVD was inserted.

I did notice that, when the fault condition ocurred, the power LED indicator on the front panel began to flicker. This flickering does not happen during 'normal' operation. In addition, there is a barely audible but distinct 'clicking' sound that seems to come from the DVD player section of the unit when the fault condition exists. This 'clicking' would seem to be at the same frequency as the LED flicker and is not audible when the unit operates normally.

One possibility that ocurrs to me is that the PSU, or a section of it, is failing. This failing section may not be able to supply enough current and/or voltage for a particular section of the unit and this may be the cause of the problems. Of course, there may be a fault that causes more current to be drawn from the PSU than that section of the PSU can supply.

I cannot find any technical documentation for this unit on the web.

Does anyone know where I might be able to get diagrams or other information that would allow me to test?

Thank you for any help you may be able to provide.

Mike

From your symptom I don't see any way to tell for sure if it's the laser, the mechanism, or the DVD main board.

For example, I have seen SRAM chips cause similar symptoms, perhaps playing a DVD with no or limited menus, and not the more common types with full menus.

I have seen mechanical problems where the sled (stepper) motor hangs, sometimes due to contamination like hair or carpet fiber.

A common failure mode for DVD lasers is to play a while, then start to pause, pixelize, stop, etc. Often after about 30 minutes or so playing time.

With the flickering of the LED there may be a power supply problem - bad caps or some such.

These days, troubleshooting DVD players is rarely economical. Easier and cheaper to replace.

Mark Z.