CRT Discharge Procedure - Revision history

Josh: /* ⚡ How to Build a Discharge Tool */

2025-05-25T08:23:56Z

⚡ How to Build a Discharge Tool

← Older revision		Revision as of 09:23, 25 May 2025
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	* '''Discharge wand (optional)''' – A purpose-built safe discharger for CRTs.		* '''Discharge wand (optional)''' – A purpose-built safe discharger for CRTs.

	== ⚡ How to Build a Discharge Tool ==		== How to Build a Discharge Tool ==

	A simple and safe CRT discharger can be made as follows:		A simple and safe CRT discharger can be made as follows:

Josh at 08:23, 25 May 2025

2025-05-25T08:23:38Z

← Older revision		Revision as of 09:23, 25 May 2025
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	* Discharge the CRT before touching or removing the analog board.		* Discharge the CRT before touching or removing the analog board.

	== 🧰 Tools Required ==		== Tools Required ==

	To safely discharge a CRT, you will need:		To safely discharge a CRT, you will need:
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	# Wrap the shaft in '''electrical tape''' to avoid accidental contact with bare metal.		# Wrap the shaft in '''electrical tape''' to avoid accidental contact with bare metal.

	== 🔌 Identifying the Ground Point ==		== Identifying the Ground Point ==

	A safe ground point includes:		A safe ground point includes:
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	* The '''analog board’s metal shield''' or '''logic board ground plane'''.		* The '''analog board’s metal shield''' or '''logic board ground plane'''.

	== 🛠️ Discharge Procedure ==		== Discharge Procedure ==
	[[File:CRT Anode Cap.jpg\|thumb\|CRT Anode Cap]]		[[File:CRT Anode Cap.jpg\|thumb\|CRT Anode Cap]]

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	Some CRTs can '''regain charge due to internal capacitance'''. After 10–15 minutes, it's a good idea to '''discharge the anode again''' before handling.		Some CRTs can '''regain charge due to internal capacitance'''. After 10–15 minutes, it's a good idea to '''discharge the anode again''' before handling.

	== 🧹 After Discharge Safety ==		== After Discharge Safety ==

	* Always verify the CRT has been discharged before touching or removing the analog board.		* Always verify the CRT has been discharged before touching or removing the analog board.
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	[[Category:Repair Guides]]		[[Category:Repair Guides]]
	~~[[Category:Apple Maintenance Guides]]~~

Josh at 21:36, 4 April 2025

2025-04-04T21:36:05Z

← Older revision		Revision as of 22:36, 4 April 2025
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	== ⚠️ Safety Warning ==		== ⚠️ Safety Warning ==

	Working with CRTs involves potentially lethal voltages ('''up to 25,000 volts'''). You should only discharge a CRT if you are confident and equipped to do so safely.		Working with CRTs involves potentially lethal voltages ('''up to 25,000 volts'''). '''It will kill you if you don't safely discharge it'''. You should '''only discharge a CRT''' if you are confident and equipped to do so safely.

	=== Minimum Safety Precautions ===		=== Minimum Safety Precautions ===

Josh at 21:34, 4 April 2025

2025-04-04T21:34:28Z

← Older revision		Revision as of 22:34, 4 April 2025
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			[[File:Schneider-MM12-Monochrome-Monitor-Open-3.jpg\|thumb\|340x340px\|CRT Inside a MM12 Monitor]]
	Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs.		Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs.

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	== 🛠️ Discharge Procedure ==		== 🛠️ Discharge Procedure ==
			[[File:CRT Anode Cap.jpg\|thumb\|CRT Anode Cap]]

	=== Step-by-Step ===		=== Step-by-Step ===

Josh at 21:31, 4 April 2025

2025-04-04T21:31:27Z

← Older revision		Revision as of 22:31, 4 April 2025
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	~~__NOTOC__~~
	~~= ⚡ CRT Discharge Procedure =~~

	Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs.		Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs.

Josh: Created page with "NOTOC = ⚡ CRT Discharge Procedure = Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs. == ⚠️ Safety Warning == Working with CRTs involves potentially lethal voltages ('''up to 25,000 volts'''). You should **only discharge a CRT*..."

2025-04-04T21:31:13Z

Created page with "__NOTOC__ = ⚡ CRT Discharge Procedure = Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs. == ⚠️ Safety Warning == Working with CRTs involves potentially lethal voltages ('''up to 25,000 volts'''). You should **only discharge a CRT*..."

New page

__NOTOC__
= ⚡ CRT Discharge Procedure =

Cathode Ray Tubes (CRTs), used in vintage Macintosh and other classic computers, can '''retain a dangerous high voltage charge for hours or even days''' after being powered off. To avoid '''electric shock or injury''', proper discharge is essential before performing internal repairs.

== ⚠️ Safety Warning ==

Working with CRTs involves potentially lethal voltages ('''up to 25,000 volts'''). You should **only discharge a CRT** if you are confident and equipped to do so safely.

=== Minimum Safety Precautions ===
* Unplug the system and wait at least 30 minutes before starting.
* Use only '''insulated tools''' and wear '''rubber-soled shoes'''.
* Never work on a CRT in a damp or conductive environment.
* Discharge the CRT before touching or removing the analog board.

== 🧰 Tools Required ==

To safely discharge a CRT, you will need:

* '''Flat-head screwdriver''' – Preferably with a long, insulated handle.
* '''Alligator clip jumper wire''' – To ground the tool.
* '''Gloves''' – High-voltage insulating gloves recommended.
* '''Discharge wand (optional)''' – A purpose-built safe discharger for CRTs.

== ⚡ How to Build a Discharge Tool ==

A simple and safe CRT discharger can be made as follows:

# Attach one end of the alligator clip wire to the metal shaft of a long flat-head screwdriver.
# Attach the other end to a '''ground point on the CRT''' (see below).
# Wrap the shaft in '''electrical tape''' to avoid accidental contact with bare metal.

== 🔌 Identifying the Ground Point ==

A safe ground point includes:

* The '''metal chassis''' of the CRT tube.
* The '''spring clamp grounding wire''' around the CRT funnel.
* The '''analog board’s metal shield''' or '''logic board ground plane'''.

== 🛠️ Discharge Procedure ==

=== Step-by-Step ===

# Ensure the system is **unplugged** and left off for 30 minutes.
# Attach your alligator clip to a grounded part of the CRT or chassis.
# Hold the **screwdriver by the insulated handle only**.
# Carefully slide the screwdriver tip '''under the rubber suction cup''' (anode cap) on the CRT.
# You may hear a '''"pop" or crackle sound''' — this is normal.
# Hold contact for at least **10 seconds** to allow the charge to dissipate.
# Remove the anode cap by pinching and lifting it free from the CRT.

=== Repeat Discharge ===
Some CRTs can '''regain charge due to internal capacitance'''. After 10–15 minutes, it's a good idea to '''discharge the anode again''' before handling.

== 🧹 After Discharge Safety ==

* Always verify the CRT has been discharged before touching or removing the analog board.
* Keep your discharge tool handy during repair in case you need to re-discharge.
* After completing your work, reinstall the anode cap securely and avoid twisting it.

[[Category:Repair Guides]]
[[Category:Apple Maintenance Guides]]