Panasonic AG-5710 - No Luma

[WondrousBread]

Hi all, new member here. Today I received a Panasonic AG-5710 for free, but unfortunately it has a video issue. I hope I use all the right terms; I've been around the block a few times with older video equipment but I am still an amateur on repairing anything other than an obvious problem.

I was testing it out and found that the tape loads, and audio sounds great, but the video is very dark. I am using the S-Video output. I did not test the BNC output as I don't have a cable to do so.

There are coloured "blobs" moving around the screen, which I quickly realized are people. I'm assuming that what's happening here is that the Luma signal is either not being generated properly, or there is a break in the signal somewhere before the output jack.

Doing some reading, it looks like the capacitors are the cause of most problems with these machines. I have recapped older machines before, but wanted to check in and see if there is anything obvious I'm missing before I commit the time to such a project.

I will obviously inspect while disassembling to try and see if there are any other issues, but one peek inside the machine has me a little bit intimidated

Thanks, Chris

[WondrousBread]

One easy diagnostic I did today was to just plug the machine in and let it warm up a couple of hours. Then I put in a tape I had laying around (The X-Files Movie) and noticed that it was a little better. than yesterday. I also noticed that switching the TBC off resulted in the video output being lost.

So I let the entire movie play while I did some other tasks, and by the time I came back the picture had improved vastly. It was a lot brighter and colours were more accurate. Still pretty bad, but better. It isn't perfect but it's definitely come back around some. And now it works with the TBC in either on or off positions, although noticeably brighter with it off.

So this definitely leads me to think that it's bad capacitors, since it seems like once they had some juice in them there was a noticeable improvement. I also popped the cover off again and noticed that all the caps I could see are through-hole and not SMD, which is helpful. As soon as I have time I will recap it and see what happens.

I will also try and keep track of how many of each cap is necessary and post the list, in case someone else is in the same position.

[hodgey]

The video sub-boards are plugged in on the bottom of the main pcb, and most stuff sit on the underside of that so it's hard to see much without taking the whole pcb out. Some caps may also be covered by metal shielding.

[WondrousBread]

Quote:

Originally Posted by hodgey

The video sub-boards are plugged in on the bottom of the main pcb, and most stuff sit on the underside of that so it's hard to see much without taking the whole pcb out. Some caps may also be covered by metal shielding.

Hi Hodgey;

I actually did remove the main PCB most of the way (enough to see what I was working with) but still didn't see any SMD caps. It could be that they are hidden further in though, and you're correct that I had a hard time seeing the other side of the sub-boards.

I will be disassembling the entire unit, taking lots of photos, and then thoroughly documenting everything before I order the new caps or remove any original ones.