8mm Forum: Sankyo 600 no power

This is topic Sankyo 600 no power in forum 8mm Forum at 8mm Forum.

To visit this topic, use this URL:
https://8mmforum.film-tech.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=1;t=010211

Posted by Barry Webb (Member # 1897) on September 18, 2015, 05:56 AM:

Hi I have a sankyo 600 that has no motor in forward and reverse but the lamp comes on ok.
I have tested the two motor micro switches and both seem to be good.
That leads me to the motor also tested good.
So it looks like it could be the speed controller board any ideas on that board possible fix.
Barry.

Posted by Steve Carter (Member # 4821) on September 18, 2015, 06:23 AM:

Barry those micro's can test OK, but can still be faulty, I replaced mine on the DCT and it runs OK now...

Posted by Barry Webb (Member # 1897) on September 18, 2015, 11:55 AM:

Thanks Steve but both forward and reverse micros give as new readings and motor is fine that's why I think I maybe the speed control board playing up.
There is no intermittent drive and only lamp is getting power.
Also the transformer is working fine.

Posted by Janice Glesser (Member # 2758) on September 18, 2015, 12:01 PM:

There's a transistor connected to the speed board located behind a heavy heat-sink plate. This may have gone bad also.

[ September 18, 2015, 01:24 PM: Message edited by: Janice Glesser ]

Posted by Steve Klare (Member # 12) on September 18, 2015, 12:36 PM:

The whole thing is where the voltage stops along the way to the motor: that's where the problem is.

The catch is gaining access to the conductors to measure the voltages can be tricky.

As far as the micro switches go, I'd be more suspicious of them if the motor ran one direction and not the other. There are different contacts within them for forward and reverse.

-but!

Murphy's Law dictates if something can go wrong, it will go wrong. So even if the probability is only tiny it is the switches at fault, you can't dismiss it entirely!

Posted by Barry Webb (Member # 1897) on September 19, 2015, 06:52 AM:

Thanks Janice tested the transistor and its bad will pop out and pick one up later and report back.

Posted by Barry Webb (Member # 1897) on September 26, 2015, 07:25 AM:

Well after a wait for the correct transistor I fitted it and still no go.

Posted by Janice Glesser (Member # 2758) on September 26, 2015, 01:23 PM:

Thanks for the update Barry. Now it gets tricky. As Steve has already pointed out locating where the power stream is disrupted can be challenging. Please keep us posted on any progress. The Sankyo 600 is basicially a good machine and several people on the forum including myself have one...or two [Smile]

From what you have done already sounds like you are pretty comfortable around a voltmeter and soldering iron [Smile]

, so any feedback on your troubleshooting is very much appreciated.

Posted by Steve Carter (Member # 4821) on September 26, 2015, 01:27 PM:

Barry does that transistor screw into the heat-sink, if so some thermal paste is used and make sure it's tight, i've had transistors that fail because they are not tight on the heat-sink. I still think it's the micro's...

Posted by Steve Klare (Member # 12) on September 26, 2015, 09:09 PM:

Barry,

Do you have some kind of voltmeter there?

If you measure the voltage from collector to emitter on your new transistor we may be able to learn a lot about what's going on. (These should be two easily accessed measurement points.)

You can think of the transistor as kind of a valve that controls how much current flows through the motor. If there's never any voltage, something is probably disconnected. If it's always all the voltage, the motor controller isn't telling it to let current flow through the motor. The voltage at 18FPS should be more than the voltage at 24FPS.

UBB.classic^TM 6.3.1.2