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HD1000 long tape record/playback issue  

post #1 of 34
Thread Starter 
Been fighting this for days now. Watching the end of a tape
the picture is all messed up here and there. The heads are fine. But I have noticed one thing so far. I take a t120 tape and its fine the whole way through. But is I use T160 tape, at around the last 10 to 20 mintues is starts to loose it. I have tried this on two tapes and the same. I also watch the end of The green mile on a t182 and it was messed up at the need. Can one use t160 and t180 tapes on the HD1000? Anything special one has to do? Are there adjustments in the machine? Etc? Pulling my hair out.


post #2 of 34
I have played back many 160, 180 and even 210 tapes and never had any problem with any of them.

Maybe you have one of those demo things that have all kinds of problems.

post #3 of 34
Never had a problem using any length ST160, 182 etc. You said T-160 and I can tell you that T-xxx is a standard VHS designator while SVHS is ST-xxx. Maybe you meant SVHS tape and just used the number for VHS grade by mistake. Point is that VHS tape IS unreliable at any length but some have reported better results than others with it. I get perfect quality from SVHS tape, any length and totally poor quality on VHS tape at any length. DVHS tape also is perfect quality at any length.

I suggest you compare your VCR using one of the DVHS tapes as a test. You may be in need of a factory realignment to make your VCR work like the rest of us have. Any test with SVHS tape will probably get you a "Use DVHS tape only" from the repair tech as SVHS tape is not officially supported on the PVHD1000 for digital recording. We just know it works here.

Don Landis
Home Theater Pics at: www.scubatech.com Last updated 3/25/01

[This message has been edited by Don Landis (edited 05-20-2001).]
post #4 of 34
Thread Starter 
I meant ST since yes I am using S-VHS tapes.

One another thread, someone talked about tape tensioning.
I couldnt find the thread again but am interested in more input on this. I am going to go back and look at any 160 tape I have recorded and check them. So far I am 2 for 2.

This machine is not a demo machine.

post #5 of 34
I have had nothing but bad experiences with Maxell XRS ST-180. Because of this, I am now using trying the Maxell ST-180 BQ, which so far seems to be Ok.

"better living thru modern expensive electronics"
post #6 of 34
Thread Starter 
I looked at some more ST-160 tapes I recorded and found another where at the end it loses it. So far I have found it only does it towards the end of long tapes.

So is there a spec for tape tensioning? Can this go out.
Be adjusted? Does the HD1000 have a spec for tape length?

post #7 of 34
Save those bad tapes if they're important. They'll be readable in another machine.

I've started experiencing erratic behavior on a couple of my machines, and head cleaning didn't seem to help. The problem started with block noise near the end of Panasonic DF300 tapes, and then got worse and started affecting recordings on other brands and lengths of tape. I moved the machine to work to attempt repair and the darn thing fixed itself! The climate is different at work than at home, so I suspect that if a machine is a little out of tune it doesn't take much to make noise appear. I've even had experiences where just a FF/RWD has restored clean playback.

I've read that older machines have more problems of this type because the upper cylinder becomes "too polished". The air boundry between the tape and the cylinder gets too thin. That, in turn, destablizes the tape path and motion.

The back tension spec on the HD1000 is 20 to 25 grams. There are three setting positions for the tape tension spring. Changing the tension will affect the tape path, so a lot of things have to be adjusted afterwards. A good tension gauge costs about $500.

Regarding longer tapes, I've had fewer problems with the DF420 and 480 tapes than with ST120's.

- gridleak... biased toward HD
post #8 of 34
Thread Starter 
What do you define as block noise?
And how do you know it "fixed" itself?

I have seen two issues. One is where the picture freezes.
I here this is a known bug in the setups. Have only seen twice.

Whats happening at the end of some longer tapes it I get these big blotches of green on the screen as well as pixcels. If I rewide these areas, where its been it stays.
But again, I have only seen it on the end of 160 and 180 tapes. But not sure if all because if generally does it at the last 10 minutes. Before that seems okay.

So could one send the unit back and have it adjusted?
Doesnt sound like anyone has really had this issue yet?

post #9 of 34
Thread Starter 
My latest data.

No matter what I do, I can not cause issues with a ST-120.
But on the St-120 and St-182's, it messes up towards the end.

I put in on DF300 that I have and recorded the last two mintues and worked like a champ.

Seems like the longer tapes are bad for my HD1000 and I need to use the DF300 and DF480's if I may not want to mess up stuff.

Still want to try my 160 tapes in another machine but ...

post #10 of 34
Okay, both gridleak and h2ofun have now mentioned DF-480 tapes. I've never seen these nor heard of them. Who makes them, and where can you get them?

Neither Tape Warehouse nor Tape World lists them on their Web sites.


Ron Gomes
post #11 of 34
Thread Starter 
Not sure if they are df480 or 420. Seem for sale from Japan. Not cheap.

Just went and tried my St160 tapes in another persons HD1000. For the tapes I brought that had issues, the same on his. We then recorded over the much less dropouts.

So now I am going to try and measure the write current and compare to others.

Step by step.

post #12 of 34
Try passing your tapes once through another machine before recording on the PV-HD1000. I've had tape shed problems at the beginning and end of brand new tapes. Once they've been recorded on once, though, the problem disappears upon re-recording.

post #13 of 34
DF480 tapes are made by JVC. I've never found a source in the US. They're about $50. I use them to troll for good stuff on PBS-HD -- just record four hours each day and then check back to see if I got anything worth keeping.

- gridleak... biased toward HD
post #14 of 34
Thread Starter 
Lets see. I measured the write voltage on my consumer deck
and it was 90 mv. So I moved to the spec and put it at 109 mv. Sure didnt fix the issue, may have made it worse.

So I watched 10 ST160's that I had made. None of them were over about 135 minutes. None of them had an issue. But if I record in the last 10 minutes, blocks. Weird. Again, at the end of my D-vhs tape its fine.

So for folks using 160's can you try recording on the last 5 minutes of the tapes and see what you get?

post #15 of 34
It does look like back tension is the culprit here. On a machine that's working properly back tension varies only slightly from beginning to end on any tape, and increases slightly as the tape diameter on the supply reel approaches 1 inch. This increase in tension will be the same for all tapes, so the last 5 minutes of a 120 will be at the same tension as the last 5 minutes of a 160.

However, 160 and 180 tapes are thinner than 120's so they might react differently on the head cylinder as the tension increases. It's also possible that your machine has too much drag in the supply reel which would prevent the back tension device from working properly.

Your tension spring is probably in the middle position. Try it in the lower tension position

- gridleak... biased toward HD
post #16 of 34
Originally posted by gridleak:
DF480 tapes are made by JVC. I've never found a source in the US. They're about $50. I use them to troll for good stuff on PBS-HD -- just record four hours each day and then check back to see if I got anything worth keeping.

What is your source for the DF 480 tapes?

post #17 of 34
Oops, I think I stepped in it!

I got them from the the guys I bought my JVC DH30000 recorders from (not Kwon). The tapes were part of the recorder purchases. They have indicated that they don't like to be hassled with small orders and email inquiries, so I don't feel free to broadcast their address on the forum. If enough people are interested I could contact them and see what they want to do. It might be a good item for the AVS Country Store.

- gridleak... biased toward HD
post #18 of 34
Just wanted to add that I've just started to experience the "end of longer tape green splotch breakup problem." My immediate solution has been to use longer tapes. http://www.avsforum.com/ubb/redface.gif

I use a spreadsheet to track recordings and it has a formula to calculate the tape length for me, based on program running time. I used to have it set to assume the actual length of the cassette (e.g. allow 162 minutes on an ST-160). I've since changed the formula to assume a couple of minutes under the rated time (e.g. 158 for an ST-160, 175 for an ST-180).

I know this is not a long term solution, and remain concerned about the root cause. Would tensioning be likely to be off after 1-200 hours use?


[This message has been edited by peterd (edited 06-15-2001).]
post #19 of 34
Thread Starter 
I have been fighting this same issue and have not found root cause. For now I am not going to use s 160 tapes since the problem does not happen at the end of Dvhs 150 tapes.

If you find root cause, let me know. It does not happen at end of S 120 tapes. Does happen at end of s 182 tapes.

post #20 of 34
Originally posted by peterd:
Would tensioning be likely to be off after 1-200 hours use?
No, probably not, but 200 hours is a significant portion of the total video head life. Near the end of their useful life they are more susceptible to clogging, and more sensitive to normal variations in tape tension.

What have you tried so far? Have you cleaned the cylinders, video heads, and A/C head, by hand with alcohol?

Earlier you said you changed the record current and it made it worse. That reading needs to be made with a wide band digital scope with a built in 20 mhz low pass filter. I'd recommend returning the setting to what it was, unless you're very sure of the scope

- gridleak... biased toward H

[This message has been edited by gridleak (edited 06-14-2001).]
post #21 of 34
Thread Starter 
Had my dad involved in my process since he has more years of experience than I am old http://www.avsforum.com/ubb/redface.gif)

We cleaned the heads even though everything was super clean.

We spent a lot of time calabrating the scope we used before we took measurements.

I have tried different S tapes and D-VHS tapes. The only piece of data is I have never seen the issue with a 120 tape. Never. But I see it at the end of pretty much all 160 and 182 S tapes. I tried one 160 tape that was bad in my hd1000 and used another persons. Even though it was much better at the same place at the end of the tape, it still had some drop outs.

I have taped at the end of a few D-VHS tapes and have never seen the issue.

So about all I can do now is use my s 120 tapes with no concern. I will be using D-VHS tapes for up to 150 minutes.
But for 3 hour movies, am still concerned I cant use my full 182 S tapes. SO I may have to be watching the movie
at the 2 hour point and stop and put in another 120.

So if anyone else finds root cause, sure would be interested but since these machines are only speced I believe for digital on D_VHS tapes, who knows.

post #22 of 34
Wearing out the tape head is something I haven't worried much about until now.

Does anyone know what the life expectancy of these types of heads are? And about what it costs to replace?

Also, what's the best way to clean this head? The service center told me to use a non-abrasive cleaning cartridge. Is it better to get in there with a swab or something?


[This message has been edited by Mike2 (edited 06-14-2001).]
post #23 of 34
Thread Starter 
I am interested in the head life question also. I easily have over 200 hours of taping just since I have had my HD1000.

post #24 of 34
This site is an excellent source of VCR repair information. Somewhere in the faq it says that the heads will last about 500 tapes (1000 hours), and the lower cylinder (the part that doesn't spin) about 5000 hours. The numbers apply to VHS. D-VHS heads are narrower, shallower, and have tighter gaps, so I'd bet they wear faster than VHS heads.

There's head cleaning info in the faq, and also in this forum. I know Don Landis has posted on the subject. Swabs (#VHK27 head cleaning sticks) can be purchased from Panasonic Parts .

Heads cost $231.44 if you do it yourself (see this thread) . Panasonic would probably add another $90 labor

- gridleak... biased toward HD
post #25 of 34
Thanks gridleak.

I'm past 1500 hrs here so I guess it won't be long. http://www.avsforum.com/ubb/frown.gif
post #26 of 34
I have the same problem at the end of a fuji t-160. If I stop the tape and restart it it plays for less than a minute and deteriorates again.

It seems clear that tape tension is the probable culprit. Either dvhs 150 tapes are 10 minutes shorter because its the physical limit of reel weight
to keep tension tolerable or their is extra backing to reduce stretch on a 150 tape. Another factor could be the quality of friction reducers in the tape cassette.

I think I may send the Maxell 160 and 180 tapes I ordered back and go with dvhs150 tapes.
post #27 of 34
Thread Starter 
I was getting the issue greater than 10 minutes back from the end of the t160. Once it was past 10 minutes, I figured I might as well use a 150 Dvhs that I know works.

post #28 of 34
Thread Starter 
I am now having issues with S-VHS 120 tapes. I have seen on a tape at the beginning and then went away. I taped last night and it was at the 2/3 rd point and wouldnt go away. I will try various tapes tonight and then use a DVHS tape to see whats happening. I had already cleaned the heads. Could my heads need to be replaced? Sure am thinking to going 100% with DVHS tape but have to try a few didnt tapes tonight.

post #29 of 34
I have been using ST120 and ST160 S-VHS tapes (FUJI and Maxell Professional), and DF300 D-VHS tapes (JVC and Panasonic) with a JVC DM-30000 and have experienced no problems with any of these tapes. I suspect that this experience suggests that the problem is related to the recorder and not to a specific brand of tape.
post #30 of 34
Thread Starter 
Okay, I took Rogers lead of purchased the head assembly that he recommended. Had it in 3 days. Took 2 minutes to put in. Tried the tapes I was having issues with, all gone.
I even played the 180 I had issues with at the end and gone!
Will try a few more tapes before victory but if this keeps up, I will be purchasing another one for a spare just to make sure since it looks like once they start going, thats it.

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