Horizontal green lines

[Skolink]

I have just set up a TiVo for someone including a PAL tuner mod, and it is displaying flickering horizontal green lines on live TV (a line every few seconds).
I found this post http://forums.oztivo.net/showthread.php?t=96 recommending replacing the board. However reading this post http://archive2.tivocommunity.com/tivo-vb/showthread.php?t=70268&page=1&pp=30 implies that in most cases this problem could be fixed by updating to software version 3.0.1.A1-01-1-000. As you know the version we all use is 3.0-01-1-010.
Does anyone have a copy of whatever files are in the 3.01A update so I can try them?

It would be less hassle than replacing the MPEG encoder chip (of which I happen to have a spare).
Thanks,
John

[Darren King]

Software upgrade won't fix it. You'll need to replace the Sony CS22 MPEG encoder.

[petestrash]

We have tried the A1 version before, and it has not fixed the green line flash.

A temporary fix may be to just add a heatsink to the mpg encoder, but as Darren has said the unltimate fix is to replace it.

Peter.

[Skolink]

I've replaced the Sony CXD1922Q MPEG encoder and the green lines are still present! I suppose it could still be one of the associated components eg capacitor or crystal.

Darren, do you think it could be the SAA7114H video decoder?

Peter, any chance you could find that software?

Thanks,
John

[petestrash]

We probably should have got you to check whether it's an encoding or decoding problem first.

can you download one of your recordings and watch it on your pc and see if the green line is present.

From memory we merged the changes in 3.01a into the current r1.6.2 OzTiVo release.

Due to a failure of my Raid5 array a few months ago, I no longer have the virgin US 3.01a image.

Peter.

[Skolink]

Good thinking Pete, I had just assumed that it was in the recording process, not the playback (due to all the posts I had read). Now I've proved it.
I finally managed to get TyServer going, single socket connection was the secret.
The green lines are still present when the .ty file is played back on the PC.
Now to decide what to fix..

[petestrash]

Most of the time it is the encoder.

Darren is the hardware expert here. I believe he is away for a few days though.

Peter.

[Darren King]

Well, next thing on the list is the SAA7114H. If it is still present then I'm stumped as it is either the CS22 or the SAA7114H.

[petestrash]

If the recording has green lines, I don't see how it would be the Saa7114H.

Peter.

Edit: wrong chip ignore this post.

[Darren King]

The SAA7114 is the input video switcher and filter which is in the recording circuit.

You are thinking of it's counterpart, the SAA7120, which is (in simplistic terms) the reverse of the SAA7114 on the playback side.

[petestrash]

:o Yep, your right.

Lack of sleep here...

Peter.

[Skolink]

By "video decoder" I'm using the terminology in the SAA7114H datasheet which is confusing. It is not decoding from a digital format but 'decoding' the transmitted analog signal to video + sound (and doing the switching and filtering as you say).
Anyways, since the lines look to me a bit like an intermittent noise or interference fault, I might first try replacing the caps around the SAA7114H, since I don't have a spare IC.
Darren do you mean to keep referring to the CS22, since that is the digital video decoder? That isn't the problem since the .ty files played back on the PC *still have the lines*, so it is in the recording. I assume you mean the CXD1922Q?

[petestrash]

A Little confused :confused:

In post 6 you said the lines were still there on playback on the PC, but the last post you said the lines were gone.

Peter

[Darren King]

Darren do you mean to keep referring to the CS22, since that is the digital video decoder? That isn't the problem since the .ty files played back on the PC fine. I assume you mean the CXD1922Q?

Yes, sorry. I do mean the Sony CXD1922Q. Like Peter it is lack of sleep (and not actually looking at a TiVo motherboard as it is a bit hard while working away remote from my desk).

Also like Peter asks can you clarify that you are NOT seeing the green lines when playing TY files on the computer?

[Skolink]

A Little confused :confused:

In post 6 you said the lines were still there on playback on the PC, but the last post you said the lines were gone.

Peter

Too tired - was almost midnight. I've fixed the post. Sorry for the confusion.

[Skolink]

Replacing the SAA7114H IC did not fix this problem unfortunately.

I finally got around to ordering some SAA7114H ICs from Digikey to fix 3 TiVos I have. The intermittent horizontal green lines are still there after replacing the SAA7114H chip. It could actually be something to do with the tuner input, so I will test with the AV inputs (I should have done that first).

The other two TiVo have a "no video input" problem. I replaced the SAA7114H on one of them but it did not resolve the issue. I will try replacing the IC on the third TiVo anyway.

[Darren King]

The other two TiVo have a "no video input" problem. I replaced the SAA7114H on one of them but it did not resolve the issue. I will try replacing the IC on the third TiVo anyway.

If either of these have a kernel log along the lines of "Could not CXD Boot" then your problem will most likely be the Sony MPEG encoder, or maybe the two VRAM chips hanging off this MPEG chip.

[Skolink]

Well whats weird is that about a day after I replaced the SAA7114H and discovered the green lines were still there, they dissappeared. A week later and they're still gone. What is stranger though is a new problem appeared. During playback or live TV there is an occassional flicker of an image at the bottom of the screen. I looks like part of the image overlaid, covering about the bottom 10% of the screen, and happens about once every 30 seconds. It doesn't happen in frame-by-frame playback. The flicker is not present when the .ty files are played on the PC. The flicker can be seen on both composite output and UHF output.
This indicates the problem is in the playback / digital-analog section of the TiVo.
Anyone seen this symptom before?

[Skolink]

Yesterday I tried changing the horizontal resolution on our main TiVo to 720 (yes after owning it for 4 years), and what do know but an intermittent flicker appeared at the bottom of the screen, just like on the 'faulty' TiVo. It even has a heatsink on the MPEG decoder.
I checked on the faulty TiVo and sure enough the horizontal resolution was set to 720 (I don't ever recall changing it). I set it to 544 and now there is no flicker!
All fixed finally
I'm surprised no-one mentioned that the flicker is a symptom of the horizontal resolution being set to 720.

[petestrash]

The green flicker is caused by the chip working harder than it is currently able to. These chips ability appears to degrade over time.

How were we to know you were running in 720 mode? all you originally said was that you had just set up a TiVo, which usually mean 544.

Anyway with the heatsink on and running in 544 it should give you some time before further degradation.

Peter.

[catdog]

I'm surprised no-one mentioned that the flicker is a symptom of the horizontal resolution being set to 720.

I have seen the same flicker with the resolution set to 720... changed back to 544 and it went away again. Sorry I missed your original post or I would have suggested checking the resolution setting!

[Skolink]

To clarify, the TiVo had two issues, intermittent horizontal green lines, and then the inverted image flicker at the bottom of the screen.
The green lines were fixed by replacing the SAA7114H chip, and the image flicker at the bottom of the screen was fixed by setting the resolution from 720 back to 544.