IBM 8512 VGA Monitor, 12"

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IBM 8512 VGA Monitor

Preliminary Information
Release Year	1987
Leak Risk	Medium
Batteries	None
Mounting Technology	Through Hole
Capacitor Types	Aluminum Electrolytic, Tantalum, Ceramic, Polymer
Destructive Entry	No
CRT Guides
General Information · Repair Cautions

IBM's first generation VGA display released with the IBM PS/2 computer line.

Known Issues

As a first generation VGA monitor, the 8500 series has its shortcomings. A dot pitch of 0.41 makes the display fuzzy and monitor dims noticeably when drawing light-colored screens, though this is considered a design flaw, not a sign of failing components. There are several known maintenance issues which are detailed in the link below.

Power Supply Failure / Squealing / Clicking

Causes

• Blown filter capacitors (line or transformer side)

Solutions

• Replace line filter capacitors in power supply.
• Replace larger capacitors
• Consider complete recap.
• Use low-ESR capacitors at output

Monitor Turns Red

Causes

• Neck PCB capacitor failure
• Output / driver transistors on neck PCB (see repairfaq.org link in Related Links)

Solutions

• Recap Neck PCB
• Possibly recap color gun circuitry under EMF shielding on main PCB

Disassembly Notes

When replacing caps located under the EMF shielding, be careful to note capacitor heights for the taller capacitors (C340, C354, C357) if the EMF shielding is to be retained. Experience suggests EMF shields may not be necessary for reliable operation - YMMV.

Original Parts

Main (9979800001) and Neck (9979800002) PCBs

NOTES:

1. All capacitors listed below are through-hole mounted aluminum electrolytics.
2. All capacitances are micro Farads (uF).
3. Capacitors C100 - C400 are located under the EMF shielding (near RGB pots)
4. Capacitors C400 - C700 are located in the horizontal / vertical control circuitry (middle section of board to flyback)

Main PCB 9979800001 (rev 04 and 08) - Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Diameter/Size	Temp	Series	Notes
C115, C215, C315	2	0.47	50
C113, C213, C313	3	1	50
C106, C206, C306	3	4.7	25				BI-POLAR
C108, C208, C308, C352	4	4.7	50
C101, C201, C301	3	47	16				BI-POLAR
C104, C111, C114, C204, C211, C214, C304, C311, C314	9	47	16
C350	1	100	16
C356	1	100	16
C353	1	100	25
C340, C354, C357	3	470	25
C503, C620	2	1	50				C620 not present on rev 08
C753	1	1	250
C412	1	2.2	50
C401, C516, C556, C601, C602, C751	6	4.7	50
C355, C413, C515, C557, C752	5	10	50				C557 not present on rev 04
C537	1	22	160
C545	1	22	250
C408	1	33	16
C622	1	33	25
C554	1	33	35
C555, C604	2	47	25
C405, C414	2	100	25
C425	1	100	35
C534, C609	2	220	16
C552	1	220	25
C416	1	330	35
C514	1	470	25
C428	1	470	35
C550	1	1000	25

Neck PCB 9979800002 (rev 05 and 07) - Capacitor Specifications and Footprint Information

RefDes	Qty	Capacitance	Voltage	Diameter / Size	Temp	Notes
C853	1	1	100
C804, C814, C824	3	1	250
C806, C816, C826	3	2.2	315
C842, C844, C850	3	10	100
C843	1	47	16

Replacement Parts

Basic PCB Name

Capacitors

RefDes	Qty	Compatible Part Number	Order Links
			Digikey

If parts are not available or different selection is preferred, you can use the values in the Original Parts section to perform a parametric search.

Kits

• Digikey BOM: https://www.digikey.com/

Related Links

• IBM 8512, 8513, and 8514 maintenance and repair notes on repairfaq.org