Don Dumitru - Got Blog?

If you have an HTPC with a Digital Cable Tuner, there seem to be a variety of things that can go wrong. Here are some of the things I've read about or experienced, gathered together into what I hope is a convenient resource.

(I'm not going to try to define terms like "HTPC" or "Digital Cable Tuner / DCT" or "Clear QAM" or "CableCard". If you see a term here you don't understand, you should do some web searches to get an understanding of what it means.)

Dead-On-Arrival Digital Cable Tuner

Just reading the forums, it seems like a surprising number of people have experienced the "DOA DCT" problem. I guess we're spoiled - we're not used to buying something, taking it out of the box, and it's dead and it needs to be replaced. Manufacturers have gotten better than that - except that they apparently haven't. I personally had a DOA DCT, and I've seen postings by at least two other people who also personally experienced it. Given that less than a hundred thousand people (guessing) have purchased machines with DCT's, to hear about that many failures is pretty surprising. But there it is.

What does a DOA DCT look like? For me, I tried to get my DCT's working without CableCards first, before I called Comcast to come out - I didn't want to waste a bunch of effort with Comcast until I was sure that I was ready for them. So I tried to use my DCT's with analog and Clear QAM signals. With two DCT's, what I saw was that using the tuner diagnostics in Media Center, one tuner was consistently able to show a signal, and the other tuner always showed a black screen. When I swapped the coax cables between the two tuners, the working one was still working, and the dead one was still dead. I called Velocity Micro tech support, and they had me uninstall the driver for the DCT in Device Manager, reboot, let the driver reinstall, and try again - the dead one was still dead. Velocity Micro shipped me a new DCT, and the new one works.

Poor Signal Strength

It seems like the DCT's are not able to operate with low signal strength - in cases where your cable set top box is working fine, if you connect that coax to the DCT, the DCT will show "No Signal". So the hardware (or firmware) in the DCT seem to just not be as tolerant of low signal strength.

To test this, try to remove as many coax splitters as possible - connect your DCT as directly as possible to the signal coming from the street. If Media Center's tuner diagnostics can show a signal when you are connected directly to the signal from the street, but can't show a signal when you have splitters in-place, then it sure sounds liek a signal strength problem. You can either try to actually configure with fewer splitters, or you can look into getting a powered amplifier.

If you have a cable co. tech out to install your CableCards, the tech should be able to put a meter on the line and check the signal strength. (I assume you can also purchase a cable signal strength meter, though I would guess they are probably too expensive to justify buying one for household user.) If the tech does the testing and there is a problem, it is possible that the tech will supply a free-of-charge powered amp (or at least so I have read, in some forum postings).

Dead-On-Arrival CableCards

(See comments above about, Isn't is reasonable to expect that a new product out of the box, isn't defective?)

Some brands of CableCards seem to be notorious for being defective. (Some brands of CableCards also seem to be notorious for not being compatible - ATI released new firmware for the DCT's, one feature of which was to work-around out-of-spec behavior by some brands of CableCards.) Again looking to postings on forums, you see various stories about one CableCard not working, and then swapping in another one and it works.

What does a non-working CableCard look like? I don't know for sure. You would think it would be something like, the DCT can tune analog and Clear QAM when the CableCard is not inserted, but with the CableCard in-place, you can't tune. You might get a black screen, or "No Signal", or some message related to you not being authorized to view the content. (This seems like it would be very easy to get confused with the Mis-Paired CableCard, see below.)

The best option here seems to be to hope that the tech (if you are not trying a self-install) comes with spare CableCards, so you can swap them around until you get a working one.

Mis-paired CableCards

To pair the DCT to the CableCard, somebody needs to type in several numbers into the cable co's computer system: The serial number of the CableCard, and two numbers from the DCT. If a single digit of any of those numbers is wrong, it's not going to work.

So, is the CableCard mis-paired, or is it DOA? I don't know how to tell the difference, other than if you can get the person on the phone to re-key the data, and it starts working, then it was probably mis-paired.

[Edited 13 Nov 2007.]

Some people have reported that they could tune some channels, but not others - when they attempted to tune the others (often, a premium channel like HBO) they get a brief bit of the signal and then a report that they are not authorized to view that channel.  In at least one case, a poster on the forums indicated that this was actually a case of a mis-paired CableCard.  It didn't work to have the cable co. just send another "hit" - they had to explicitly ask the cable co. to erase the configuration fields and re-key the pairing data, and then their service started working.

I strongly recommend that when you pair your CableCards, you have the operator read-back the numbers they have enterered, so that you can verify them against the numbers on your screen.

Can't View All Of Your Premium Channels

Some people on the forums tell stories about how they can view some of their premium channels (say, TNTHD), but not others (say, SHOHD). The most likely cause here seems to be that the cable co. has mixed up records in their computer system. They need to send discrete signals down the cable line to the CableCard, to authorize it for every individual channel, and if their computer system doesn't have the right records in all of the right places to say that you have a particular channel, then you aren't going to be able to view that channel.

The only solution is to get the cable co. to somehow clean up their computer records.

It seems to me that this scenario (messed up computer records) might be more likely to happen if you were the customer of a smaller cable co. that got purchased and merged into a larger cable co. As part of the merge, the two companies would have to migrate all of the records, which of course is an opportunity for something to go wrong.

Digital Cable Tuner Showing "Safe" Mode

[This section added on 13 Nov 2007.]

The ATI Digital Cable Tuner has its own firmware.  In some circumstances, this firmward can apparently get corrupted, and the tuner stops working as a tuner.  If the tuner's name changes to include "(Safe)" in its title, then the tuner has detected that it has corrupt firmware, and gone into "safe mode" (this is not the same as Windows "safe mode", but it is a similar concept).

When in "Safe" mode, the only function the ATI Digital Cable Tuner will support, is flashing a new firmware version.  So if you see your DCT stop working in Media Center, and its name has changed to "(Safe)", you should try flashing new firmware onto the tuner (you can download the firmware from ATI aka AMD).  If flashing new firmware doesn't work, then your DCT is almost certainly now "dead", and needs to be replaced.

I recently purchased a Velocity Micro Vista Media Center machine, with two internal Digital Cable Tuners. I'll blog about the machine later, for now I'm just going to recount my experience getting the CableCards installed with the Comcast tech.

Prior to the install, I had Media Center auto-configure the tuners, and I did the "Setup additional services" to let it detect the clear-QAM channels. I used the tuner diagnostics to verify that both tuners were working and could receive both analog and clear-QAM channels. Only once that was working did I call Comcast to schedule an install. (Since the CableCards get paired to the tuners, if I had a bad tuner, they would have to come out again to re-pair for the replacement tuner. And in fact I did have a bad tuner that needed replacing - I'll include that story in another blog.)

I live in the Seattle area. I called the Comcast number, and they were able to schedule a tech to come out a couple of days later, in a 4 hour window. They said they would call before they showed up, but, well, no phone call, just the ringing doorbell. The tech had never done a Media Center install, but I'm pretty sure he had done some Tivo installs. Overall he was polite, but...

He inserted the 2 CableCards, and the PC didn't recognize them. I checked the CableCards, and they weren't fully inserted - you have to push them in firmly. The PC still didn't recognize them - on a hunch, I took them out and turned them over and put them back in. Now the PC recognized them.

How did I know that the PC recognized the CableCard? If you go into the Network applet in Vista, the Digital Cable Tuner(s) (DCT) will appear as a network device. You can right-click and pick "Device Web Page", and it will launch a web browser against the DCT, and let you view the status. One part of the status is the "Card" page. If the CableCard is not recognized, this page will show that the CableCard is not inserted. Once the CableCard is inserted and recognized, if you manually refresh this page, it will change to give you more information, including a bunch of new links.

One of those links is for "pairing" the CableCard. You need to click on that link to open new browser window, and it will show you additional information. There are several items that the cable co. will need in order to pair the CableCard to your tuner. They need the CableCard serial number - write this down before you insert the CableCards, since the serial number is not visible with the CableCard inserted. They also need the "host" and "data" ID numbers, and these are displayed on the new browser window. Make sure you have all 3 of these numbers before you call into Comcast.

And verify the numbers very carefully. If a single digit is wrong anywhere, it's not going to work. When the tech was reading the numbers over the phone to the operator, I was checking them against the screen, and when he mis-read one, I corrected him. (And the operator was not reading the numbers back - I hope that they have lots of practice, and don't make mistakes often. The system really should have a "checksum" number that the operator reads back - the operator would input the numbers into their system, and the system would generate a checksum, and the operator would read it back. The web page would calculate the same checksum, and display it. If the read-back doesn't match the web page, you'd know that a number was keyed in wrong.)

Another thing to be careful of: If you have multiple DCT's, you need to know which CableCard is inserted in which DCT. In the software, the DCT's have a 4 digit number to identify them - their serial number. This is a number like 3CF8 or 078D - this number appears on the web page for the tuner, and it appears in Media Center for the tuner. So ahead of time, use the Media Center diagnostics, and disconnect one coax cable at a time to make the signal go black, and figure out which tuner is what serial number. I printed small labels with the serial numbers, and pasted them above the slots on the back of the PC, to identify which DCT was which serial number.

Then, I recommend that when the CableCards are inserted, that you look at the serial numbers of the CableCards, and insert the lower-numbered CableCard in the lower-numbered DCT. That way, you'll know which is which. When you call in, you have to give the right CableCard serial number, to match the host and data ID of the DCT that the CableCard is inserted into.

Once the tech had called into the operator, the operator sent a "hit" to each card. You can view the "traces" for the DCT on the device web page - the "traces" are debugging messages that the DCT software writes when things happen. In the browser, edit the URL for the device web page, and change the "index" to "advindex" and open that page. Then navigate to the section that had the big black text box and the buttons underneath it - click the button to show the traces. If you have the traces showing when the "hit" comes down, the traces will update with not-very-easy-to-understand messages, that somehow tell you what happened. (I found the debug messages to be pretty unintelligible.)

After that, I started Media Center, brought up the Guide, and went to one of my local TV stations that is available in HD. I hit record to lock that tuner to that channel, then used the guide to tune HBO HD, SHO HD, and Mojo, to verify that premium HD channels were being brought in. I had no problems in this regard. (I've heard some people say that their premium channels don't come through on CableCard, and this can often be blamed on the cable company's database system not properly authorizing the CableCard for all of the channels that you are subscribed to.)

Finally, I will say that I kind of complained about the need to have a tech come out (I was way more knowledgable about this process than the tech was), and he said that they should have CableCards in their stores with the other equipment, and that I should be able to pick up the CableCards and do a self-install. I'm planning on doing the registry hack to install two more DCT's in my PC, and I will definitely attempt the self-install for those.

The paperwork he gave me suggests that I payed $14.99 for "UPGSEPTRIP", $1.79 for "TIVO CC3 AD", and $5.10 for "DIGI AD PKG". I will be carefully watching my monthly bill, to see how I actually get charged.