CurtPalme.com Home Theater Forum

[skippyar]

Hello all,

Got the dreaded combo as the topic states.. Cleaned up all modules, fixed dry-joints on some modules, tested *all* resistors, transistors, chips, diodes, (not caps) to no avail.

Removing both Vertical and Horizontal boards clears SF but still fast blinking HTHD, but having either/both boards then SF and HTHD, could I assume both boards are knackered?

When this fault happened in the past before it became permanent I simply powered off the projector waited 20minutes, tried again and it would be fine for another 2-3 hours. So I figured perhaps is was the dry-joints warming/expanding and causing a short - but obviously not.


* Tested safety resistors (convergence board) - ok.

It's had a rough life of previous owners, I've tried my best to refurb/maintain, but these types of issues test the limit of my proficiency - any thoughts would be appreciated.

I'll probably end up sending all the modules to Mr Palme for testing.

Paul.

[Curt Palme]

What model?

The HTHD light is for the voltage that drives the H output board. If there's a scan fail issue, the HTHD voltage will be shut down to prevent spot burn on the tubes. (The HV also gets shut down by the scan fail).

So, a scan fail will always trigger the HTHD shutdown. Ditto for the reverse, if the power supply is bad and outputs no HTHD, there's no H deflection, and the SF will turn on.

If it's intermittent, check the master width trimpot on the SMPS (power supply). Too low or too high a setting, and the SF will also be triggered. Again, to prevent tube phosphor line or spot marks.

Without getting into the SF circuits, you can't tell whether it's the SMPS, H or V boards that are causing the error. I had one BArco long ago that I spent hours on trying to find the SF cause. Turns out the SF line runs through the video boards, and a bad one caused the SF as well. That was one set though in the 100s of Barcos I've worked on.

[Curt Palme]

What model?

The HTHD light is for the voltage that drives the H output board. If there's a scan fail issue, the HTHD voltage will be shut down to prevent spot burn on the tubes. (The HV also gets shut down by the scan fail).

So, a scan fail will always trigger the HTHD shutdown. Ditto for the reverse, if the power supply is bad and outputs no HTHD, there's no H deflection, and the SF will turn on.

If it's intermittent, check the master width trimpot on the SMPS (power supply). Too low or too high a setting, and the SF will also be triggered. Again, to prevent tube phosphor line or spot marks.

Without getting into the SF circuits, you can't tell whether it's the SMPS, H or V boards that are causing the error. I had one BArco long ago that I spent hours on trying to find the SF cause. Turns out the SF line runs through the video boards, and a bad one caused the SF as well. That was one set though in the 100s of Barcos I've worked on.

[skippyar]

Thanks for the reply. Mine's a 500 Data, forgot to mention I'd checked every fuse too..

I kinda get the feeling I've got a very obsure fault with mine at the moment. All the obvious testings (short of getting the out) are just turning up nothing.

I haven't got the schematics for the 500 Data so I wouldn't know exactly which trim pot is the Master width. All pots are still sealed. (I did notice that a previous owner had messed with the V-HOLD-L and V-HOLD-H on the vertical module.)

I'll have another go at testing it this evening, I just hope I don't have to stack it next to the Seleco SVP-350 in my "to fix" corner.

Cheers,

Paul.

[Curt Palme]

Well, I'm selling working and tested H and V boards for $10 each plus about $55-60 shipping, so that would be one way to solve it. THe V hold pots tweaking won't put you into scan fail mode.

[Curt Palme]

Well, I'm selling working and tested H and V boards for $10 each plus about $55-60 shipping, so that would be one way to solve it. THe V hold pots tweaking won't put you into scan fail mode.

[skippyar]

They are very good prices Curt. I think I'll more than likely arrange to have the modules shipped to yourself. I know from experience with my Seleco SVP 350 faulty SMPS the cost/hassle of replacing just components doesn't warrant it and makes more sense to just swap out with a complete module.

I best get saving.

Thanks again for the support and feedback.

Paul.

[draganm]

[skippyar]

Yes! Absolutely.

Thanks for the response draganm.

Paul.

He's down and disassembled at the moment. Some hardware pron for those interested: https://picasaweb.google.com/skippyar/BarcoCRT#

[skippyar]

Still persisting with this, though inevitably I'll purchase replace modules. In the meantime it's still educational.

(Keeping in mind I still have my existing SF fault).

Referencing my 17+ test point I noticed the 17+ trimpot when turned up full can only achieve 15.66v. I've metered various components that pertain to the trimpot and all seems ok - so where should I be looking for current loss?

Thanks for any input.

Paul.


Disassembled and refurbished the back today. Also using Curt's tips section I was able to address and verify what I'd done against the outlined fault pointers guide.

[Curt Palme]

That could well be the issue. That point needs to be at 17 volts, under 16 and even without the SF, the pix will blank out. Something is wrong with the SMPS I'd think. CHeck the other outputs to see if they are equally low..

[Curt Palme]

That could well be the issue. That point needs to be at 17 volts, under 16 and even without the SF, the pix will blank out. Something is wrong with the SMPS I'd think. CHeck the other outputs to see if they are equally low..

[skippyar]

[skippyar]

[Curt Palme]

Sure, email me at curtpalme at shaw.ca

Thanks!

[Curt Palme]

Sure, email me at curtpalme at shaw.ca

Thanks!