IBM 8512 VGA Monitor, 12"

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 to the IBM 8512 page on repairfaq.org (see )

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

Causes

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

Solutions

 * Recap Neck PCB
 * Test transistors on neck 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.

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)

Neck PCB
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