77
edits
576/Repairs: Difference between revisions
→Some Defects without symptoms. NOTE: Just because I did not see "symptoms" does not mean that they were not there, simply that I was not experienced enough to find any such symptoms.
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==Some Defects without symptoms. NOTE: Just because I did not see "symptoms" does not mean that they were not there, simply that I was not experienced enough to find any such symptoms.== | ==Some Defects without symptoms. NOTE: Just because I did not see "symptoms" does not mean that they were not there, simply that I was not experienced enough to find any such symptoms.== | ||
Found D507-D708 9V Zener VR TC shorted (continuity both directions) on both Step Gen and Display Board. | Found D507-D708 9V Zener VR TC shorted (continuity both directions) on both Step Gen and Display Board. Could these be related to other previously discussed problems or repairs? | ||
Tek's recommended replacement is a [[1N936]], available at [https://www.mouser.com Mouser Electronics]. | Tek's recommended replacement is a [[1N936]], available at [https://www.mouser.com Mouser Electronics]. | ||
D507 was replaced with a TC Diode, D708 was replaced with a standard 9V ZENER (not TC, did not have the proper part on hand) | D507 was replaced with a TC Diode, D708 was replaced with a standard 9V ZENER (not TC, did not have the proper part on hand). | ||
RESULT: -75V drifts badly as the machine is turned on and heats up (High @ -73.5V when turned on and drifting slowly to -75.05V when warmed up.). | RESULT: -75V drifts badly as the machine is turned on and heats up (High @ -73.5V when turned on and drifting slowly to -75.05V when warmed up.). | ||