585/Repairs: Difference between revisions
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==HV low and trace invisible== | ==HV low and trace invisible== | ||
:'''Symptom:''' No trace, HV low despite maximum setting | :'''Symptom:''' No trace, HV low despite maximum setting | ||
:'''Root cause:''' HV [[Bumble Bee capacitors|PIO "Bumble Bee" capacitors]] leaky (~180 μA at 2 kV) | :'''Root cause:''' HV [[Bumble Bee capacitors|PIO "Bumble Bee" capacitors]] leaky (~180 μA at 2 kV); no trace because CRT grid too negative wrt. cathode | ||
:'''Solution:''' Replace caps | :'''Solution:''' Replace caps | ||
:<gallery> | :<gallery> |
Revision as of 02:47, 4 May 2019
Supplies out of regulation
- Symptom: Several supplies out of regulation
- Root cause: dry HV electrolytics
- Solution: Rebuild caps using modern replacements
Remove defective cap
Cut can near base, remove guts
Fit modern cap
Epoxy cap onto base
HV low and trace invisible
- Symptom: No trace, HV low despite maximum setting
- Root cause: HV PIO "Bumble Bee" capacitors leaky (~180 μA at 2 kV); no trace because CRT grid too negative wrt. cathode
- Solution: Replace caps
old PIO caps in place
old PIO caps removed
new ceramic caps
No trace
- Symptom: Trace invisible
- Root cause: Wiper of focus pot not in contact
- Solution: Disassemble focus pot, clean and re-seat wiper
- --Peter (talk) 02:45, 4 May 2019 (PDT)
Trace disappearing
- Symptom: Trace fading after ~10 minutes operation
- Root cause: HV resonant cap (C808) leaky, overheating (visible bulge)
- Solution: Replace cap
Time base inoperative
- Symptom: No trace
- Root cause: Lead of neon bulb in Miller integrator (B171?) broken
- Solution: Solder replacement lead after grinding away some glass (or replace neon)
broken lead
repaired leads (before encapsulation with epoxy)