28.63636 Crystal Resonator

[The Bishop]

I have several defective DVR card that I removed from PC based security systems that I built due to the pci card unable to control a steady picture. I call the cards, "Jumpy," and replaced the card with a new DVR card.
Now the maker of the DVR card has stopped production of this amazing card, along with the software we have come to trust.

In an effort to try to save a few cards I replaced the 5 Caps on the cards just in case, but it did not solve the jumpy problem.

I'm now looking into the 28.63636 Crystal Resonator on the cards.

Could the Crystal Resonator be defective?

I'm good at replacing Caps if defective but new to the actions of a Crystal Resonator.

Every DVR card failed due to power fluctuations, power outages and the shock of power restorations and nearby lightning storms.

 

[ronsimpson]

Could the Crystal Resonator be defective?

Yes, they are a little sensitive to mechanical shock. (don't drop it on the floor)
28.63636mhz is a common number. You can order some. Do you have known good parts that you can switch out? If you have a good and bad board and switch parts you will learn something.

 

[AnalogKid]

What are the manufacturer and part number for the card? Now that the system is out of production, the manufacturer might let you have the schematic (maybe with a non-disclosure agreement).

That crystal frequency is suspicious - Was the card processing non-high-def, NTSC video?

Photos?

ak

 

[The Bishop]

Yes, non-high-def, NTSC video.

I picked up the DVR cards online about ten years ago with security software. Since then I've tried several other similar DVR cards online but they will not run the software from the old cards.
I don't like the other card sellers security software, so I am trying to repair the old version DVR cards.

I have about 8 DVR cards that failed and would like to replace any parts that's defective. The 5 caps are new now.
My family has learned the old security software and don't want to change. If I can repair the cards I can maintain the old software.
My main question is would a Crystal Resonator cause picture or video instability?

 

[Nigel Goodwin]

Every DVR card failed due to power fluctuations, power outages and the shock of power restorations and nearby lightning storms.

It's VERY unlikely a crystal would be damaged by lightning, much more likely are semiconductors - and in complex devices like these the prime suspects would be ones with smaller construction techniques, which are more easily damaged by large voltage spikes.

 

[AnalogKid]

Nigel beat me to it, and (unfortunately for you) I completely agree. Sucks.

ak

 

[The Bishop]

Thanks for the information,

On a pci DVR card like mine, is there a suspect device that might cause a jumpy picture?

It's not a bad jumpy picture for viewing, but under motion detection the image needs to be still. What I have is a constant recording on the security cameras.

I need this because in the last three years we have had twice now, burglars staging themselves at our gates. We live in the country and traffic down our country road is almost non existent at night.
Twice though, thanks to our security system, we got enough video for others in the community to recognize at least one suspect during each attempted break in.
Thanks to local people, and neighbors of friends sticking together reported back to us with enough information to give to the police to get an arrest on both videos.
In the last break in, the mother of the suspect that got out of the back seat with a pistol in his hand identified her son in my video.
He told his mother he was going out with some friends that night. He was 23years old and still living at home.

 

[AnalogKid]

1. Are there any components on the bottom side of the board?

2. What does "jumpy" mean? Unwanted vertical movement? Horizontal? Random direction? Tearing or breakup in only part of the frame? Whole-frame movement? Video-related (bright flash makes things jump)?

Does the board mux four video inputs into one recording, switching among the 4 inputs in sequence? Or record a quad split showing all 4 inputs all the time? Or record 4 video streams?

Does the board have a monitor output that is switchable among the 4 inputs?

ak

 

[The Bishop]

The DVR card is very simple. As in the photo above, very few components. The board is one sided also.

I did change out a re-moveable chip that three of the bad cards have in common. the other cards have the same chip but it's soldered on, but it didn't correct the problem.
These cards were inexpensive DVR cards but it's the outdated software that is so easy to work. I have bought some other dvr cards but they do not work the old software.
The cards only have 4 bnc camera ports and act as separate video inputs.

I was hoping for a particular device on the cards that would affect the image. The problem is the 4 camera images when displayed thru the DVR card jump, very small distortions, but it's enough for the motion dection to start recording the movement.

 

[Nigel Goodwin]

Like I said, complex chips get killed by lightning, in your case the big one under the heatsink - there's not much else on the board.

 

[AnalogKid]

My guess is that you've tried this, but I've got to ask-

Performance with only 1 camera? Two? Three?

Musical chairs: Image jumpiness changes when cameras are rearranged among the four input connectors?

Is the overall character of the jumpiness identical among all bad boards?

ak

 

[ronsimpson]

I call the cards, "Jumpy,"

It is true that a unstable clock will cause trouble.
It very likely the front end of the card is damaged. (where the video cable plugs in) If the board can not decide syncs the video will jump.

 

[The Bishop]

Thanks for the great help, I'll order a dozen of the 28.63636 crystal just to have on hand. I was hoping to rule that one out but I'll continue the testing.

You have a choice on the DVR card via the software, for all four video ports, or you can chose just 1 port on screen.

But all four video camera ports will jump a tiny bit, but that's enough motion to trigger the recording. And all 4 ports or video you see on the screen jump but not at the same time. It's a very random jump with the 4 ports and all 4 ports do not jump together or at the same time.

Even if I unplug any three cameras the single camera on screen will jump or shake just enough to start recordings.

 

[schmitt trigger]

On NTSC tv systems, a jumping screen is almost always caused by the sync separator circuitry misbehaving.

With a schematic, it is very straightforward to find the vertical and horizontal sync separators. And indeed, they use RC time constants to discriminate the vertical from the horizontal sync.

 

[The Bishop]

Today a pack of 14.31818 crystals came in the mail for another project of mine.

Not knowing much about crystal size and differences, I have to ask, How close does a crystal have to be? I know in Capacitors you can give a little up on uf and voltages.
Can you change any on crystal?

 

[Nigel Goodwin]

Today a pack of 14.31818 crystals came in the mail for another project of mine.

Not knowing much about crystal size and differences, I have to ask, How close does a crystal have to be? I know in Capacitors you can give a little up on uf and voltages.
Can you change any on crystal?

No, the entire reason for using a crystal is it's very high accuracy, which is why it's specified to five decimal places.

Think of it as the wheel nuts on your car, if you lose one can you replace it with one half the size?.