07-07-2018, 03:03 PM
Hi Trevor,
The system switch in my DR101 does need that "kick" so that switching between line standards can be achieved more efficiently. But the solenoids are wired in to the circuit in a different manner.
System switch problems came back. OK changing from 625 to 405 but 405 to 625 had once again become unreliable.
In an attempt to improve the switching over between line standards a spring has been fitted between the switch lever and the front edge of the chassis.
Let's see how long this bodge repair lasts?
Comment from Pieter H UKVRRR:
I think the issue with the DR31/101 construction is the lack of a spring construction, it is a symmetrical arrangement, which is very tricky. Normal coil/solenoid-operated relays always have some form of a spring that pulls it to a neutral position in the absence of current through the solenoid. That's clearly missing in this arrangement and it will thus exhibit some form of sticking, also because it has to overcome the mechanical friction forces of the large switch assembly.
I therefore still think, like I described in my earlier post, that the capacitor C65 that is temporarily put in parallel to the "target" solenoid is there to provide some resonance in an effort to overcome the "sticking".
The attachment shows the spring fitted to improve switch over from 625 to 405.
Geordie McBoyne
The system switch in my DR101 does need that "kick" so that switching between line standards can be achieved more efficiently. But the solenoids are wired in to the circuit in a different manner.
System switch problems came back. OK changing from 625 to 405 but 405 to 625 had once again become unreliable.
In an attempt to improve the switching over between line standards a spring has been fitted between the switch lever and the front edge of the chassis.
Let's see how long this bodge repair lasts?
Comment from Pieter H UKVRRR:
I think the issue with the DR31/101 construction is the lack of a spring construction, it is a symmetrical arrangement, which is very tricky. Normal coil/solenoid-operated relays always have some form of a spring that pulls it to a neutral position in the absence of current through the solenoid. That's clearly missing in this arrangement and it will thus exhibit some form of sticking, also because it has to overcome the mechanical friction forces of the large switch assembly.
I therefore still think, like I described in my earlier post, that the capacitor C65 that is temporarily put in parallel to the "target" solenoid is there to provide some resonance in an effort to overcome the "sticking".
The attachment shows the spring fitted to improve switch over from 625 to 405.
Geordie McBoyne