Kind friends:
This is to inquire as to whether any of you are aware of (or have suggestions to offer) as regards an acceptable (even if less than ideal) method of repairing low impedance (Spec: high current) connections to electron tubes where lead{s} are broken/severed flush with the envelope-to-metal seal?
Granting that repair of high impedance (i.e. Low I, high E) connections may be readly acomplished, I've yet to discover or devise a practical remedy for low impediance connections....
Specifically: I've a quantity of NOS YU181s wherein the former owner 'snipped' the cathode pins/leads flush with the envelope (a long, and, I might add, rather sordid story!)
Inasmuch as said lead{s} must continuously carry 25A and withstand power-up inrush surges of at least 100A, 'common solutions' (e.g. conductive adhesives, etc ) are of no avail -- Although I've had marginal sucess with 'spring loaded' contact schemes, such have proven less than reliable -- nor does any manner of welding seem an option for the proximity to the (relatively 'delicate') seal...
FWIW inasmuch as each end of the rather low impedance cathode 'filament' is (although similarly 'snipped') accessible -- and, better still, said filament is roughly 'center-taped' to the the metallic 'exhaust nipple' (an 'undocumented' connection in all YU181s and certain other Eimac 'Power Grid'' tubes) I'm envisioning some manner of electrochemical process by which leads may be attached (à la 'electroplating' techniques)? ...
Any ideas, thoughts, wild guesses or 'magic spells' will be greatly appreciated!
With very best regards and advance thanks!
HP
This is to inquire as to whether any of you are aware of (or have suggestions to offer) as regards an acceptable (even if less than ideal) method of repairing low impedance (Spec: high current) connections to electron tubes where lead{s} are broken/severed flush with the envelope-to-metal seal?
Granting that repair of high impedance (i.e. Low I, high E) connections may be readly acomplished, I've yet to discover or devise a practical remedy for low impediance connections....
Specifically: I've a quantity of NOS YU181s wherein the former owner 'snipped' the cathode pins/leads flush with the envelope (a long, and, I might add, rather sordid story!)
Inasmuch as said lead{s} must continuously carry 25A and withstand power-up inrush surges of at least 100A, 'common solutions' (e.g. conductive adhesives, etc ) are of no avail -- Although I've had marginal sucess with 'spring loaded' contact schemes, such have proven less than reliable -- nor does any manner of welding seem an option for the proximity to the (relatively 'delicate') seal...
FWIW inasmuch as each end of the rather low impedance cathode 'filament' is (although similarly 'snipped') accessible -- and, better still, said filament is roughly 'center-taped' to the the metallic 'exhaust nipple' (an 'undocumented' connection in all YU181s and certain other Eimac 'Power Grid'' tubes) I'm envisioning some manner of electrochemical process by which leads may be attached (à la 'electroplating' techniques)? ...
Any ideas, thoughts, wild guesses or 'magic spells' will be greatly appreciated!
With very best regards and advance thanks!
HP