This is topic Chinon super 7000 sound projector in forum 8mm Forum at 8mm Forum.
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Posted by Frank Raschella (Member # 5035) on September 13, 2015, 02:14 AM:
I have problem with a Chinon 7000 8 mm sound projector in that when you switch it on it powers up but the motor does not start when you turn the knob to thread or forward. Its a brand new unit I bought it in 1979 if I recall and I used it about three times. Its been in the cupborad since till last week when I wanted to use it and it no longer works. Does anyone have any ideas as to what the cause might be?
Posted by Andrew Woodcock (Member # 3260) on September 13, 2015, 03:33 AM:
Test the motor outside the machine Frank. Then you will know if it is the motor or circuitry or a mechanical bind that's at fault.
The circuit supply can then be easily traced if the motor tests ok externally by using a multimeter.
Mechanical binding can be traced by testing at various stages with parts removed from the drive chain. Spur gears, belts and the likes
Posted by Joe Taffis (Member # 4) on September 13, 2015, 01:23 PM:
Take off the back cover and check the belts. If it's like the 7500 model it has a rubber motor belt and a long metal spring type belt at the top...
Posted by Frank Raschella (Member # 5035) on September 14, 2015, 09:21 AM:
I had already pulled the back cover off and removed the drive belt of the main motor to see if it wasn't a binding issue but got nothing. Is it possible there maybe a fuse somewhere the drive the motor that may have blown?
Posted by Frank Raschella (Member # 5035) on September 24, 2015, 07:37 AM:
I removed the back cover replaced the two 2A fuses with new ones, the motor started and ran a few seconds and then it all stopped again. Clearly there is short somewhere. I bumped up the fuse rating to see if I could get to restart but all I got was a little bit of smoke from the switch connected to the knob on the other side, hence I switched it off immediately. It could well be that its the switch thats malfunctioning if so does anyone have a switch or does anyone know where I could get one or can it be replaced with something else. Any ideas would be helpful.
Posted by Andrew Woodcock (Member # 3260) on September 24, 2015, 09:22 AM:
Oh dear. I am sorry to say Frank, that by the sounds of things, you did exactly what you should never do.
The fuse is there to stop component damage in the event of an overload or short circuit situation.
You may now have done irreparable damage now to any number of components and your machine now may be well be damaged beyond economical repair unfortunately.
Posted by Frank Raschella (Member # 5035) on September 24, 2015, 05:28 PM:
Yes I am well aware that increasing fuse size can do irreparable damage but in this case its not that bad at all. I had the same smell and smoke come from the machine it when I first turned it on so I assume the fuses blew then. I am going to see an electronics specialist and see if they can shed any light on the issue. From what I can see everything is fine mechanically and the electric motor is fine also. The issue is is likely to be in a switch or similar. Will let you how I go.
Thanks for the advice so far.
Posted by Andrew Woodcock (Member # 3260) on September 24, 2015, 05:35 PM:
No worries Frank and hope the machine is still very much repairable for you.
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