Sony BVH-3100PS - drum not spinning / servo issue

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Andreas Wideroe
Posts: 2
Joined: Wed Apr 19, 2017 6:54 am

Sony BVH-3100PS - drum not spinning / servo issue

Post by Andreas Wideroe » Wed Apr 19, 2017 9:02 am

Hi,
First time posting here. Just came across this forum while googling for some help.

I have a Sony BVH-3100PS (in PAL mode) here in my facility that is used every now and then.

I haven't used if for several months, but today I got 10 reels I need to transfer and unfortunately the machine is giving me some headache.

First of all, I'm not an engineer, all though I have gained some experience over the years running this telecine/scan/digitizing facility, so I should be able to check and perhaps modify some things with the right directions. In advance, any help is very much appreciated. :D

Ok, here's what's happening:

I turn on the machine, load the tape (the vacuumfeeder works). Machine is loaded and I press standby. Then see here what happens:

https://youtu.be/7LcVtYWTWZg

I have also included some pictures I took.

Hope someone can assist me in getting this back to life again.

Thanks and best regards,
Andreas
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Andreas Wideroe
Posts: 2
Joined: Wed Apr 19, 2017 6:54 am

Re: Sony BVH-3100PS - drum not spinning / servo issue

Post by Andreas Wideroe » Wed Apr 19, 2017 3:04 pm

After hours of fiddling around, reading the manual, trying out stuff I got it working again by helping spin the drum by hand. Gave it some speed and after a few times it caught on. Now it works again, also after the machine was shut down and then turned on again.

See here: https://youtu.be/eteAUtLzWqk

Does anyone have any idea what could cause this? Almost like some lubricant/oil/grease that had dried up or become harder or something.

/Andreas

oldtvgear
Posts: 2
Joined: Thu Apr 20, 2017 6:46 am

Re: Sony BVH-3100PS - drum not spinning / servo issue

Post by oldtvgear » Thu Apr 20, 2017 6:54 am

There is a problem with some Sony BVH3100 series head assemblys where the bracket at the back starts to crack/warp with age. What happens is that as it warps, it will get closer to the disc at the back of the whole assembly, eventually crashing into it and completely seizing the drum entirely.

The bracket is a piece that has been cast from some type of molten metal, and its not clear why some brackets degrade in this way and others dont, i think it may be improperly cast parts.

I would suggest it a good idea to open the back of the machine and check if the bracket in question is showing signs of cracking or warping. I am thinking it may be and was close enough to actually start to seize the drum, the disc actually has some sort of grease on it, so by moving by hand you may have pushed it out the way enough...not ideal thing to do.

Please see this article i wrote not long ago about the problem which explains it deeper with images to make more sense.

https://www.linkedin.com/pulse/1-inch-v ... s-paterson

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