Panasonic BTH1350Y studio rgb monitor repair - AVS Forum
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post #1 of 3 Old 07-25-2011, 05:50 PM - Thread Starter
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Not sure if this is the right place to post this but,

I picked up a Panasonic BTH1350Y rgb monitor over a year ago by now, and haven't looked at it for over half a year since last I tried any troubleshooting.

My adventures with it are pretty well explained in the following thread on KLOV, where I first thought to ask for some advise: *left blank until I have 3 posts to be allowed posting urls*

Of course, even if I knew this place was around then, I didn't think to ask about it on here until now. I'm definitely interested in getting this thing going again and using it for rgb out on a lot of my old game consoles.

For convenience sake, here's the important info my my post on klov:

"Well, pre opening it up it behaved as follows:

Powers on tube energizes/fills with static etc, then after the usual warm up there was no vertical drive, just a single squashed bright horizontal white line. The adjustment knobs only moved the line around and the size knobs (h size, v size etc) only succeded in barely making the line fatter. Sounded like a cap issue to me, especially since the wg k-7000 i think it is, in my double dragon squashed to a similar horizontal line after a period of "random earthquakes" and a cap kit and reflowing of some cold joints fixed it.

So I open it up and start taking it apart, this thing has no less than 6 daughterboards, it's definately not your typical "basic" old arcade rgb monitor. Much more complicated circutry, and really nicely laid out, every cable is labled with a letter and number (like E20) to correspond to the place it goes silkscreened on the boards.

Since I had no where near enough caps to cover even half of this beasts entire amount of caps, I reflowed the solder on the entire bottom side of the main mobo, parts of some of the smallest boards, and the HOT area of the one large board. Said section on large daughter board consists of only two large line filters, a fuse, and one of those large square white resistors.

Basically it uses a standard pc ac plug, the hot and neutral wires plug directly into said seperate HOT part of one daughter board, the live into the fuse, the neutral into the resistor then both go through two line filters, afterwards a cable connects the two lines to the push power button on the front control panel then a cable from there to the main pcb's HOT area.

I also replaced a few of the electrolytic caps that I had equivalents or better on hand, very few actually.
When I realized I had no where near enough to cap it all without making an order, I stopped after maybe 5 caps, all on the main board.

Pieced it back together, and no less than quadruple checked all connections. Turn it on and immediately I am greeted with a rather loud whine. The tube still enegizes, static and all, but the sound is REALLY worrisome, so I leave it on for about as long as it normally takes it to warm up and get that line, then when I have nothing I turn it off.

I've taken it apart and put it back together multiple times since, same result, no fuse is visibly blown, and all the ones i checked with my multimeter are good. I did take a quick look at the neck of the tube when it was on, and I didn't see any glow, but before when I only got the single line, I looked and don't recall being able to see the usual red green blue or any glow from the neck. Then again, I haven't really taken a close look at it since the new problem.

I checked the caps I replaced for the correct polarity and ratings, no problem that I saw. I think caps are definately part of the problem. The problem is now I have introduced a bigger problem on top. Possible I took out a diode from heat when i reflowed the main pcb? I definately suspect a power problem in the HOT section, or open/shorted transistor, diode, blown fuse on something. My expertise with monitor repair is pretty much limited to cap replacement, solder reflowing, and pinpointing a open/shorted transistor on a wg 4900 neck board (i think it was, I forget) for the green drive.

Currently in over my head on this one, til I can get a direction. Not making any parts order until I have some idea more than pretty much the shotgun approach of replacing parts one by one til it works again.

Also, I've only worked on it off an on over a period of months, it's not a high priority, but it would be nice to figure out. "

If anyone had a service manual for this model, that would be even better. I searched high and low for a pdf of it when I was actively troubleshooting it, but could only find the user manuals available, and everyplace that might have it wanted up to $10+ shipping for a printed manual.

Of course, any general tips and advise would be highly appreciated.
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post #2 of 3 Old 07-26-2011, 06:21 AM
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It is a monitor so good luck finding a manual.

I'll try to help you but monitors are on a different level from normal CRT's.
When you have a vertical collapse like you have, the vertical deflection IC is always shot in almost every case. The vertical IC may be hard to find on your circuit but usually numbers are written on it. It's either LA7838, LA7830/32/33, LA7840, LA78040, AN5521 or AN5515 that is written on it (Only one of these choices). Usually you have to replace that IC and surrounding capacitors. These are usually the only capacitors that go bad after a long time.

As for problem of it not turning on anymore...
Well, you could have joined two solders on the board.. if so, recheck your soldering

Another possibilty is that sometimes, the vertical IC will short and the monitor will not turn on. Sometimes this means it will start up again when the IC is replaced, but usually, some zener diodes will go bad too..., but this is more rare.
I'd say, all starts with replacing the vertical IC.
as for the green drive transistor(if it was on this tv you replaced it... be sure you replaced it correctly since a different type of transistor (EBC/ ECB PNP/NPN) will make the TV short...

Well good luck with this... I'll try for the manual.
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post #3 of 3 Old 07-26-2011, 06:24 AM
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Couldn't find it for free but here it is. http://www.mcmelectronics.com/produc.../P-BTH1350Y-SM
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