CurtPalme.com Home Theater Forum

[Curt Palme]

OK, I'm really stumped here, and this is a good guessing game, as I haven't put the set on the bench yet.

I sold an almost new (450 hour) Barco Cine 7 about 3 years ago to a customer that makes good use of his HT, about 1200 hours a year of viewing. He's now got 3500 hours on it. He complained of the set shutting off intermittently, and also the red would jump out of place.

I went to his place last week, and found that indeed, the H width would appear to collapse intermittently, and the set would either go blank (no image, no HV), or shut down completely. I saw it happen twice in 10 minutes while I had it on.

As for the red convergence, it was very strange. I'd converge perfectly on the test grid, then return to the image, and the red was a mile off, moreso as it got to the edge of the image.

Ignoring the shutting off thing for a sec, I finally found out yesterday that the red image would increase in size as the contrast was cranked up. That explained why the test grid looked fine each time, but as the image went to a bright scene, the red would bloom. THe catch is, it doesn't look like the red is going out of focus, and the G and B images are completely solid.

I changed a couple of boards at the customer's place, and the problems continued.

I will put the set on the bench either late today or tomorrow. For fun, I won't post what boards I changed at the customer's place yesterday before pulling the set.

I have a couple of ideas of the issue(s), not sure if the two problems are related.

Oh, one thing to add, and I'm also not sure if it's contributing to the problem: THe projector is installed about 8' away from the largest saltwater aquarium I've ever seen. 200 gallons is my guess, maybe 300. He''s got all sorts of dehumidifying equipment in the room, and there have been no HV arcing issues that I've seen, but maybe that's a contributing issue.

Anyways, post away with your ideas, I'll nail this and will post in detail what the problem(s) is.

[Curt Palme]

OK, I'm really stumped here, and this is a good guessing game, as I haven't put the set on the bench yet.

I sold an almost new (450 hour) Barco Cine 7 about 3 years ago to a customer that makes good use of his HT, about 1200 hours a year of viewing. He's now got 3500 hours on it. He complained of the set shutting off intermittently, and also the red would jump out of place.

I went to his place last week, and found that indeed, the H width would appear to collapse intermittently, and the set would either go blank (no image, no HV), or shut down completely. I saw it happen twice in 10 minutes while I had it on.

As for the red convergence, it was very strange. I'd converge perfectly on the test grid, then return to the image, and the red was a mile off, moreso as it got to the edge of the image.

Ignoring the shutting off thing for a sec, I finally found out yesterday that the red image would increase in size as the contrast was cranked up. That explained why the test grid looked fine each time, but as the image went to a bright scene, the red would bloom. THe catch is, it doesn't look like the red is going out of focus, and the G and B images are completely solid.

I changed a couple of boards at the customer's place, and the problems continued.

I will put the set on the bench either late today or tomorrow. For fun, I won't post what boards I changed at the customer's place yesterday before pulling the set.

I have a couple of ideas of the issue(s), not sure if the two problems are related.

Oh, one thing to add, and I'm also not sure if it's contributing to the problem: THe projector is installed about 8' away from the largest saltwater aquarium I've ever seen. 200 gallons is my guess, maybe 300. He''s got all sorts of dehumidifying equipment in the room, and there have been no HV arcing issues that I've seen, but maybe that's a contributing issue.

Anyways, post away with your ideas, I'll nail this and will post in detail what the problem(s) is.

[cmjohnson]

Bad deflection coil or corrosion on the deflection board due to airborne salt water vapor.

Next question.

CJ

[Curt Palme]

Not on the bench yet, but the deflection board was my thought too at first. No go, the replacement did the same thing. Ditto for the convergence board. Ditto for swapping the HV lead in the splitter (not that I'd think it would do it, but that was all I could do at the customer's house.

[Curt Palme]

Not on the bench yet, but the deflection board was my thought too at first. No go, the replacement did the same thing. Ditto for the convergence board. Ditto for swapping the HV lead in the splitter (not that I'd think it would do it, but that was all I could do at the customer's house.

[ecrabb]

OK, ignorant non-techie here... What regulates HV in these sets, Curt... The blooming sounds like poor HV regulation like cheap TV's and monitors used to do... But, then I guess why would only the red channel do it...

SC

[macgyver655]

[JustGreg]

Another non tekie lottery ticket:

Neckboard or video amp?

[Curt Palme]

Getting closer, just wrapped up a 909 here, the 708 is on the bench in a couple of hours.

The pix size changes both in H and V directions, which is why this is confusing. If it was HV, all tubes should do it.

[Curt Palme]

Getting closer, just wrapped up a 909 here, the 708 is on the bench in a couple of hours.

The pix size changes both in H and V directions, which is why this is confusing. If it was HV, all tubes should do it.

[ecrabb]

Then, we're down to the neckboard or the magnetics themselves, right?

SC

[stefuel]

HV splitter
To tired, man of few words today.

Word of the day "AmPro"

[roland@b4]

I think I might know this one
I had a machine where one colour got bigger eratically. I thought it must be a bad tube but disconnecting the HV to that tube still cause the projector to shut down. Eventually I noticed the focus change just as the image got bigger.

I would change out the focus board or the very least the focus/G2 block
Might be worth just swapping the focus leads first

[tse]

The red increasing in size both H and V sounds like the anode voltage to the red tube is decreasing. Bad connection at the splitter or anode cup?

Scott

[Curt Palme]

I swapped the R and G anode leads at the splitter. No change. From what I could see at the house, there was zero change in focus, at least not to the degree of blooming that was happening. Also, the red test pattern was solid, no pulsing to indicate HV arcing anywhere.

I got sidetracked, and just picked up 15+ LCD TVs and monitors. I cleaned the shop, boxed up 2 projectors, so this set might have to wait until tomorrow.

[Curt Palme]

I swapped the R and G anode leads at the splitter. No change. From what I could see at the house, there was zero change in focus, at least not to the degree of blooming that was happening. Also, the red test pattern was solid, no pulsing to indicate HV arcing anywhere.

I got sidetracked, and just picked up 15+ LCD TVs and monitors. I cleaned the shop, boxed up 2 projectors, so this set might have to wait until tomorrow.

[cmjohnson]

I'd still be highly suspicious of the deflection yoke. Have you swapped it with a known good spare? Strange things can happen when a coil gets a turn-to-turn short or an intermittent open condition in it.

[CIR Engineering]

[Curt Palme]

My guess is yoke as well Chris, and if not, I swap the tube. Luckily it's the red..I've got spares.

[Curt Palme]

My guess is yoke as well Chris, and if not, I swap the tube. Luckily it's the red..I've got spares.

[macgyver655]

Isn't this one of those situations where we usually say..... swap the tube with the green or blue and see if it follows?

[cmjohnson]

I'm thinking that the red convergence issue is related to the deflection issue. My reasoning is that the magnetic field created by the
deflection yoke MUST interact with the fields created by the convergence coils given their close proximity to each other. Though I
don't know the 909, my guess is that like the other Barcos I've seen, the yokes appear to be made by Sony and the convergence
coils on Sony yokes are (as far as I've seen) integrated into the deflection yoke assembly.

With the deflection yoke acting screwy, I would EXPECT the convergence to be awry as well.


If it was a bad tube issue, well, that wouldn't make sense to me as the convergence issue as described doesn't seem
to be a possible symptom of a bad tube. I've seen a tube go gassy...in fact, I once saw a blue LCP tube crack
and fail right before my eyes while it was operating. As it got gassy, the image started to swim around like it was
shining through the surface of a pool with lots of wave action going on, and then it got dim and then it flashed as it arced
over to the deflection yoke and burned the neck right off the tube...at which point the projector shut down.

So the described problem wouldn't likely be a gassy tube. Even if it did, it wouldn't explain intermittent horizontal
deflection collapse.

Could I be wrong? Sure. I'd like to learn what the final answer is in any event as if I'm wrong I can learn something new, and
if I'm right, well, that's pretty cool, too.


CJ

[CIR Engineering]

[stefuel]

OK, it's been days now. What's the problem?
Something was causing intermittent shut-down. Arc protection??? Splitter arcing through the base where it bolts to the chassis???

[Curt Palme]

On the bench today. Spent most of yesterday working on all those flat screens. I'm out of capacitors, but 85% of the monitors work.

[Curt Palme]

On the bench today. Spent most of yesterday working on all those flat screens. I'm out of capacitors, but 85% of the monitors work.