DVD player powerup problem . . . [Archive] - Audio & Video Forums


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08-05-2013, 04:17 PM
I just purchased a year 2000 Panasonic DVD-H1000 which arrived safely and unharmed and which looks pristine, as though it has never been touched by human hands. However, it refuses to power up, either with the panel buttons nor the remote.

I have some spare parts for this unit on hand and I changed both the main power transformer and the little power board that serves as the entrance of the AC power to the player. I tried different power cords, and yes, my wall outlet is live.

Something like this happened to me with a McIntosh 831 DVD player a while back. It was perfect. I shipped it to someone and it arrive refusing to power up. I was so disgusted that I just told him to keep it free of charge. I never found out why this happened.

Please tell me the next place to look for the cause of this problem.

08-06-2013, 10:31 AM
However, it refuses to power up, either with the panel buttons nor the remote...Please tell me the next place to look for the cause of this problem.
Sure sounds like a primary power issue - blown fuse. I had a similar issue with a German made GamuT CD player. Seemingly no fuse block on back so I cracked the case. No fuses to be found. Hmmm...

What I found was they used a fused IEC socket (http://www.newark.com/productimages/nio/standard/4765525.jpg). There is actually a small 5x20mm fuse inside the socket along with a spare!

Otherwise, you need a VOM to see how far the power is going. Do you find AC from the incoming socket? At the input of the power board? DC coming from the power board to the circuitry?

08-06-2013, 11:10 AM
Thanks for responding, E-Stat!

I have seen those fused IEC sockets and this is not one of them. There are two fuses on the little board just as the socket enters the unit. Both fuses are just fine.

But wait - there's more:

Late last night (more like early this morning SIGH!), I took the bottom cover off the player and discovered a larger power supply board. The Panasonic number on it is VJB91236. This board had a crack in it where a slightly heavy component (probably a small relay) was mounted. I have seen this happen before. The unit was probably dropped during shipping. Unfortunately, when I took a spare VJB91236 board from a player with a dead transport and installed said power supply board in place of the cracked one, there was no change - the player is still quite dead. WTF?!

I do have a VOM and my next steps will be exactly what you said:

"See how far the power is going. Do you find AC from the incoming socket? At the input of the power board? DC coming from the power board to the circuitry?"

I only hope that the problem is not on the main processing board (aka motherboard) because that is the one part for which I do not have a spare and while they are still available they are about $500. Moreover, I could never be sure if this was really the problem until the new unreturnable $500 board arrived and I tried it. SIGH!

Angels and ministers of grace defend us! --Hamlet

08-06-2013, 06:13 PM
Some progress late today:

I did what I could with my VOM. I am certain that a $200 per hour electronics engineer would have done much better. I am happy to report that I was able to verify that the motherboard is fully functional. I simply removed it and put it in another unit and said unit functioned perfectly with the borrowed motherboard as it did with its own motherboard and I did no harm to either motherboard.

Thus far over the past two days I have swapped every board (except the small progressive scan output board, which should not impact the power-up) with known working boards from other units and the mystery remains. Fuses and wiring have been checked. I even swapped the faceplate, since that is where the controls are. And yes, I have tried powering up the player with the remote.

At this point, my thoughts are that I should do some further swapping of the power input board and also that aforementioned cracked power supply board. The cracked board has already been replaced with a known functional board - but who knows - dung happens and the intact power supply board could be bad also, even with out any visible cracks or bad solder joints.

There is nothing practical nor sane about this endeavor. I simply want to know why a player that looks like it just left the factory in Japan a few days ago was DOA.

Oh well . . .

08-08-2013, 02:10 PM
Now I have some good news:


Yes indeed. I regret that I was at fault for not reviving it sooner. What I could not understand is that I found that the power supply board had cracked enroute and then replaced said cracked board with an identical intact board from another player. Yet, the repaired player was still not powering up and this sent me on a wild goose chase.

Well, very late last night, I decided to examine the replacement power supply board under magnification very carefully for tiny cracks in traces and solder joints, etc. It looked perfect and I was about to accept defeat (at least until I came up with a new approach) when my eye just happened to glance at where the main power cable connects to the power supply board.

Eureka! I had apparently misaligned the two-pin connector at the end of the power cable and connected to only one pin rather than both pins! So of course the board was non-functional. Now all I needed to do was reconnect the cable correctly and hope and pray that this was ALL that was wrong. And yes, thank God; we have ignition!

Morale of the story - besides being more meticulous - double check the obvious and also double box for shipment regardless of the additional expense. This is not the first time I have seen a power board or a solder joint crack from the stress of a somewhat heavy component. Proper double boxing can act as a shock absorber. I had little or nothing to say about the shipping of this player. My local UPS store manager - who is a delightfully helpful lady - tells me to always pack something assuming that it will be dropped at least 3 feet somewhere along the way. SIGH!

Angels and ministers of grace defend us! --Hamlet

(And this time they did!)