New photoelectric mod thread
Yes:
Rabco SL8E Photoelectric Servo Control Retrofit
I don't see much interest in the way of comments or questions, though.
Ray K
Yes:
Rabco SL8E Photoelectric Servo Control Retrofit
I don't see much interest in the way of comments or questions, though.
Ray K
My compliments, what nice job with all those clever modifications.
Just to share my experience, I took a less sophisticated route by:
1) Just inserted a very low Vce sat transistor between catwhisker and motor, placed close to the motor.
This reduced the current through the contacts from >11mA at start up to 0.1mA max leading to a much faster and smoother respons.
Side effect was that the crabbing step became much smaller and motor noise almost vanished because the motor never came to full speed.
Never had any problems after that with contacts getting dirty.
2) Placed shims between the carriage and the wheels to eliminate a rather large play
3) Changed the two piece Cart wiring into one piece of higher copper quality.
4) Left the vertical pivot bearing, but replaced the horizontal bearing by a knife construction made from a Stanley knife blade, resting on V shaped beds.
This resulted in a perfectly friction free vertical movement.
5) Originally I started in 1965 using the arm with an ADC25 MM Cart. Later with MC Carts, Fres was around 10Hz, so there was no reason to replace the arm with a lighter one.
And because this one piece arm is very stiff, I have no problems with unwanted resonances.
6) At a later stage I also changed the RCA sockets for WBT Nextgen RCA Sockets.
7) Replaced the ultra heavy bolt to lift the arm by a lightweight plexiglas construction resting on both sides of the lifting mechanism.
Hans
Just to share my experience, I took a less sophisticated route by:
1) Just inserted a very low Vce sat transistor between catwhisker and motor, placed close to the motor.
This reduced the current through the contacts from >11mA at start up to 0.1mA max leading to a much faster and smoother respons.
Side effect was that the crabbing step became much smaller and motor noise almost vanished because the motor never came to full speed.
Never had any problems after that with contacts getting dirty.
2) Placed shims between the carriage and the wheels to eliminate a rather large play
3) Changed the two piece Cart wiring into one piece of higher copper quality.
4) Left the vertical pivot bearing, but replaced the horizontal bearing by a knife construction made from a Stanley knife blade, resting on V shaped beds.
This resulted in a perfectly friction free vertical movement.
5) Originally I started in 1965 using the arm with an ADC25 MM Cart. Later with MC Carts, Fres was around 10Hz, so there was no reason to replace the arm with a lighter one.
And because this one piece arm is very stiff, I have no problems with unwanted resonances.
6) At a later stage I also changed the RCA sockets for WBT Nextgen RCA Sockets.
7) Replaced the ultra heavy bolt to lift the arm by a lightweight plexiglas construction resting on both sides of the lifting mechanism.
Hans
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