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585/Repairs: Difference between revisions
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(Created page with "==Time base inoperative== :'''Symptom:''' No trace :'''Root cause:''' Lead of neon bulb in Miller integrator (B171?) broken :'''Solution:''' Solder replacement lead after grin...") |
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__TOC__ | |||
==Supplies out of regulation== | |||
:'''Symptom:''' Several supplies out of regulation | |||
:'''Root cause:''' dry HV electrolytics | |||
:'''Solution:''' Rebuild caps using modern replacements | |||
:<gallery> | |||
Electrolytic repair 1.jpg | Remove defective cap | |||
Electrolytic repair 2.jpg | Cut can near base (using a small hacksaw or a pipe cutter), remove guts | |||
Electrolytic repair 3.jpg | Fit modern cap | |||
Electrolytic repair 4.jpg | Epoxy cap onto base | |||
</gallery> | |||
:--[[User:Peter|Peter]] ([[User talk:Peter|talk]]) 02:45, 4 May 2019 (PDT) | |||
==HV low and trace invisible== | |||
:'''Symptom:''' No trace, HV low despite maximum setting | |||
:'''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 with modern ceramic equivalents | |||
:<gallery> | |||
585 HV caps old.jpg | old PIO caps in place | |||
Black Beauty caps.jpg | old PIO caps removed | |||
585 HV caps new.jpg | new ceramic caps | |||
</gallery> | |||
:--[[User:Peter|Peter]] ([[User talk:Peter|talk]]) 02:45, 4 May 2019 (PDT) | |||
==No trace== | |||
:'''Symptom:''' Trace invisible | |||
:'''Root cause:''' Wiper of focus pot not in contact | |||
:'''Solution:''' Disassemble focus pot, clean and re-seat wiper | |||
:--[[User:Peter|Peter]] ([[User talk: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 with modern ceramic equivalent | |||
:<gallery> | |||
585-c808-therm.jpg | Thermal image | |||
585-c808.jpg | bulging cap | |||
</gallery> | |||
:--[[User:Peter|Peter]] ([[User talk:Peter|talk]]) 02:45, 4 May 2019 (PDT) | |||
==Time base inoperative== | ==Time base inoperative== | ||
:'''Symptom:''' No trace | :'''Symptom:''' No trace | ||
| Line 4: | Line 41: | ||
:'''Solution:''' Solder replacement lead after grinding away some glass (or replace neon) | :'''Solution:''' Solder replacement lead after grinding away some glass (or replace neon) | ||
:<gallery> | :<gallery> | ||
585-neon-1.jpg | 585-neon-1.jpg | broken lead | ||
585-neon-2.jpg | 585-neon-2.jpg | repaired leads (before cleaning and epoxy encapsulation) | ||
</gallery> | |||
:--[[User:Peter|Peter]] ([[User talk:Peter|talk]]) 02:45, 4 May 2019 (PDT) | |||
==Wavy trace == | |||
:'''Symptom:''' Wavy trace | |||
:'''Root cause:''' C786 (100 µF 25 V) has high internal resistance (ESR ~ 20 Ω) causing +12.6 V regulator circuit to oscillate | |||
:'''Solution:''' Replace C786 with new part. | |||
:<gallery> | |||
585 wavy trace.JPG | wavy trace | |||
585_wavy_trace_new_electrolytics.JPG | +12.6 v PSU with new eletrolytics. | |||
</gallery> | </gallery> | ||
:--[[User: | :--[[User:Matt|Matt]] ([[User talk:Matt|Matt]]) 08:53, 5 May 2019 (PDT) | ||
[[Category:Instrument repair reports]] | |||