Ok I did a search but couldn’t find anything on this.
Background:
This past month I upgraded to Digital Cable Television and the cable box now displays the time in lieu of the channel you are watching.
Since my cable box and VCR are stacked together on top of the TV, I wanted to have their times as close to synchronized as possible. This seemed like no big deal because I could view the seconds of the cable time by pressing a button.
Voila! About a month ago I set the times to within a sec of each other. However my VCR is almost a full min slower (51 seconds) as of last night. This is a gradual change as it was first a few seconds and has kept increasing over the past month.
What happened!? Will my VCR’s clock correct itself every so often? I have been using the VCR time for years and never noticed a time problem before.
I could see a timing differential of one or two seconds every few month or so but at this rate there will be a 12 min difference within a year.
DISCLAIMER: My VCR has an “automatic clock” that once plugged in it searches for the time via some signal sent from the broadcast antennas (or something like that). However, you can set time manually. Which is what I did to have it coincide with the Cable Box. Before then I would let it find the time itself
Based on your VCR’s capability, the problem is with the cable company.
On our digital system, the clock is usually 1-2 minutes slow, and we can’t set it of course. Something of a pain, and also tells you what’s wrong with cable companies.
Are you sure the shift was gradual? If it started drifting, then suddenly synched with the broadcast time, that could have looked more gradual than it was.
A minute a month is a high drift rate for most crystal clocks. 20 seconds per month is more typical, but you might have just got one of the not-so-good ones in your VCR.
Yeah I am sure its gradual. In fact, it is up to 54 seconds as of a few mins ago. I am going to wait and see what happens in a few days when is should be over one minute. I am hoping that it corrects it self back but I am not optimistic.
If it keeps up this pace I am going to revert back to the “auto time” and keep an eye on how that is working. Will the VCR periodically check the broadcast time after it sets itself?
Setting the clocks once doesn’t work, as you can attest. You always have to resynchronize. Two clocks will never run at exactly the same rate - they will, at best, have a “random walk” difference, even if they have the same nominal frequency, due to noise in the system. Lower quality clocks have more noise sources. If there is a drift in either clock, then the difference just gets bigger, faster.
If you want to have them read the same time, you have to synchronize both of them with some common standard. How bad the clocks are walking or drifting dictates how often you have to synchronize.
ftg, I read your post and to be honest it seems more like a conspiracy theory than an answer. All my shows are in sync to the cable’s time. Plus my cell phone’s time (which I can’t change) is much closer to the cable than the VCR. This is more of a timing issue not a time issue.
I never expected the cable time to be exactly synched with GMT but 60 seconds should take 60 seconds. The VCR seems to have the clock that is taking longer to run off a min. I plan on setting it back to “auto time” but I want to watch it a few more days to see if anything changes. However I will not trust the VCR time until I am sure it is keeping proper time. I might just put masking tape over it and forget it is even there.
swansont, yeah I understand that but it just seemed like a huge drif. A few seconds a day should not be tolerated. I under stand that if the cable is running fast and the vcr is running slow it will cause the drift to be greater faster but based on when the shows are starting it sems the vcr has the bigger problem.
I’ll ask this again: When on “auto clock” will the VCR periodically check the “broadcast time” after it sets itself? If so, that may be why I never noticed the problem before.
It depends on the VCR, I think. My VCR doesn’t seem to check, and I reset it every few months when the time is off by a minute or two. If it does check, then your speculation would be reasonable, and the manufacturer could get away with a really cheap clock with a big drift. It also may be that stacking the VCR and cable box had an effect - quartz clocks have a fairly large temperature coefficient.
Yes. This is what ftg was telling you to do. Set your VCR on auto-time and forget about your cable time. (What you’ll probably find is that now your VCR and cable will be perfectly in sync.)