Compex WP188

Description

The WP188-A and WP188-B are the newest 2-radio and 4-radio boards from Valemount. They are currently sold as standalone boards and also used in the certified Lucaya X2000 and X4000 series.

WP188 Series Common

The WP188 boards have two of the mPCI slots on each side. The boards measure approximately 5" x 8" x 1".

WP188-A Quad mPCI

The four-card version of the WP188-A has four miniPCI slots and one (late models) or two (early models) ethernet ports. It can handle up to two "high power" (XR2/XR5/XR9/KXS30SG) and two "standard" or "medium power" (WLM54 series, CM9, etc.) radios. High power cards are supposed to be on top in the X4000 for reasons of cooling.

Pictures of WP188-A Quad mPCI Board Layout

Repairing damaged boards

After a voltage surge, the WP188 may develop a short that connects the 48v power rail to ground. This can be detected and repaired. The diodes on the underside of the board near the Ethernet port marked as D1, D2, and D3 are Transient Voltage Suppressors which may protect the board from moderate surges but can be permanently shorted by excess voltage.

The symptoms can be detected as follows. First, the unit will draw too much current, triggering whatever overcurrent protection there is. Second, the mounting hole nearest to D1, D2, and D3, if isolated from ground, will show a voltage reading of +48. It is the connection of this spot to ground that produces the short circuit on the power. Third, at least one of the diodes D1, D2, and D3 will show a short in both directions when tested for conductivity.

The simplest repair is to desolder and remove the shorted diodes. Unless there is other damage, the board can then function normally, albeit with diminished surge protection. A full repair consists of replacing the blown diodes. There are numerous transient voltage suppressors on the market. Littlefuse 576-SMAJ54CA (Mouser part number 576-576-SMAJ54CA) is one that has been seen to work in practice. It seems that since it is a bidirectional version, you do not have to worry about orienting it correctly.