39,320
edits
Potentiometers: Difference between revisions
Jump to navigation
Jump to search
no edit summary
No edit summary |
No edit summary |
||
| Line 10: | Line 10: | ||
In 1962, Tek-made potentiometers started being used in many instruments. | In 1962, Tek-made potentiometers started being used in many instruments. | ||
These are typically identifiable by their gray delrin cover (and their Tek part number). | These are typically identifiable by their gray delrin cover (and their Tek part number). | ||
[[File:311-259 1.jpg|thumb|400px|right|311-259 pot in [[O|Type O]]]] | |||
They are "stopless" pots, which means that they have a detent but can be rotated through the detent. | They are "stopless" pots, which means that they have a detent but can be rotated through the detent. | ||
This feature was intended to reduce shaft and pot problems that result from excessive torque on traditional pots. | This feature was intended to reduce shaft and pot problems that result from excessive torque on traditional pots. | ||
[[File: | [[File:311-304 cracked 1.jpg|thumb|400px|right|close-up of cracked plastic part, partial fix using tightened wire]] | ||
These types tend to develop cracks in the cross-shaped plastic part that | These types tend to develop cracks in the cross-shaped plastic part that holds the setscrew clamping the shaft. | ||
Tightening that screw then causes the crack to widen, and the shaft is not clamped strongly enough anymore, causing it to slip. | |||
Trying to fix the problem using epoxy is usually not effective. | |||
Solutions require to compress the broken plastic part in a circular fashion, either by wrapping wire or slipping a machined ring or suitable steel clamp over it. | |||
Some types affected are: | Some types affected are: | ||
| Line 28: | Line 32: | ||
| [[311-259]] || 710 Ω || VAR GAIN in [[O|Type O]] (R6530) | | [[311-259]] || 710 Ω || VAR GAIN in [[O|Type O]] (R6530) | ||
|- | |- | ||
| [[311-279]] || 770 Ω || VAR GAIN in [[CA|Type | | [[311-279]] || 770 Ω || VAR GAIN in [[CA|Type CA]] (R3338, R4338) | ||
|- | |- | ||
| [[311-304]], [[311-309]] || 185 Ω || VAR GAIN in [[3A74]] (R426) | | [[311-304]], [[311-309]] || 185 Ω || VAR GAIN in [[3A74]] (R426) | ||
|} | |} | ||
==Pictures== | |||
'''311-259''' | |||
<gallery> | |||
311-259 1.jpg | | |||
311-259 2.jpg | | |||
311-259 3.jpg | | |||
</gallery> | |||
'''311-279''' | |||
<gallery> | |||
311-304 cracked 1.jpg | close-up of cracked plastic part, partial fix using tightened wire | |||
311-304 cracked 2.jpg | |||
311-304 cracked 3.jpg | |||
</gallery> | |||
'''311-304''' | |||
<gallery> | |||
Tek 311-0304-00 pot.jpg | 311-0304-00 pot, VAR GAIN in a 3A74 | |||
</gallery> | |||
[[Category:Repair issues]] | [[Category:Repair issues]] | ||
[[Category:Electromechanical components]] | [[Category:Electromechanical components]] | ||