Unit starts on its own every 30 seconds

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qwerty
Posts: 1
Joined: Fri Apr 16, 2010 11:03 am

Unit starts on its own every 30 seconds

Post by qwerty »

Hi, is there anyone still reading this? I have one of these JVC videos and I still use it every day. In my opinion, there has never been anything able to replae it, because it can rewind/pause analog inputs, such as satellite/cable TV.

It seems that I have the same problem as Lop1 mentions in his post at the bottom of the 'cloning' thread: http://cippico.com/bbs/viewtopic.php?p= ... light=#578

Basically the machine starts up by itself, has some kind of error and shuts down. 30 seconds later, it starts again. It is possible to switch it on and then everything works normally butit goes back into this error if it is switched off or put into timer-record mode.

Does anyone know of a solution? I'm hoping it's something simple like dust in the VCR mechanism blocking a sensor. (I never use mine to play tapes.)
evogt
Posts: 2
Joined: Sat Feb 05, 2011 5:41 pm

Re: Unit starts on its own every 30 seconds

Post by evogt »

Hi,
qwerty wrote: Basically the machine starts up by itself, has some kind of error and shuts down. 30 seconds later, it starts again. It is possible to switch it on and then everything works normally butit goes back into this error if it is switched off or put into timer-record mode.
My unit is starting to misbehave in the same way as yours, especially after it has been unplugged for a while. I'm guessing it is an electrical problem, probably with the stand-by power supply.The unit is acting as if it has lost power when it enters stand-by mode and starts the boot-up procedure again and again. Mine eventually succeeds entering stand-by mode after being left on for a while (as if something had to heat up inside), but I fear it will only get worse with time. :(
--
Etienne Vogt.
evogt
Posts: 2
Joined: Sat Feb 05, 2011 5:41 pm

Re: Unit starts on its own every 30 seconds

Post by evogt »

evogt wrote:.The unit is acting as if it has lost power when it enters stand-by mode and starts the boot-up procedure again and again.
Ok, I got the reboot problem fixed by replacing two electrolytic capacitors on the switching power supply circuit board (C5207 and C5208). Now the unit stays in stand-by mode again. :)
But I still have another problem with this recorder : poor SVHS playback with a noisy image especially on SVHS-ET recordings, with small black & white dots and even black & white horizontal stripes on some tapes. Of course, these tapes play fine in another SVHS deck.
I tried carefully cleaning the video heads and tape guides, but playback quality did not improve. :( Visual examination of the video heads shows no sign of damage or wear. Any idea where to look next :?:
--
Etienne Vogt.
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andywilks
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Joined: Mon Jan 24, 2005 11:38 am
Location: Pendle Witch Country, Lancs

Post by andywilks »

under (inside) the video head there is a copper slip ring and carbon brush that runs round it that provides earth to the head to discharge any static build up. That causes your symptoms.
It's a common problem for that brush/ring to need cleaning.
2 screws removes the green drive board. note the position of the brass top/green board you take off as the drive board position is critical to keep alignment. slide the head up carefully and you will see the bits needing cleaning in the bottom.
you will need a small allen key. the one I have I ground shorter to fit better
werner
Posts: 1
Joined: Sun Jan 29, 2012 10:19 am
Location: Schwechat, Austria

Thanks for help....

Post by werner »

Today I finally took some measurements of the standby power supply of my HM-HDS1 which suffered from same problem, did not turn on at all anymore.
Found indeed ripple on the +40V and -30V lines from Standby power, +40V was much less than it should be. Have changed the two capacitors mentioned in this thread and now working again....thanks to those who contributed here !
Now will find a Diamondmax 16 (this is the disk inside now) to do a copy to keep it alive a little longer....
kind regards Werner
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andywilks
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Joined: Mon Jan 24, 2005 11:38 am
Location: Pendle Witch Country, Lancs

Post by andywilks »

Glad we are still able to help in some small way.

At work, we have given up on these models now, as everyone wants more modern PVR recorders with HD etc, so they are all obsolete.
I'm not sure how much longer we can be of use.

regards
Andrew
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