• Compaq 188987-001
• Compaq 188826-001
• Compaq Presario 7100 series (486)

• DALLAS RTC coin cell empty

The motherboard's Real-Time Clock (RTC) chip contains a coin cell that may have drained, causing the loss of CMOS settings. This can result in an inability to save settings, causing system instability or failure to boot. To fix this, the RTC chip can be replaced with an equivalent or repaired by cutting into it and soldering on a new external coin cell holder. Replacement guides are available at https://github.com/necroware/nwX287 or https://github.com/necroware/nw12887, depending on the actual chip used.

Used in Compaq Presario 71xx series, 7200 series.

Riser Board is 188820-001 (Compaq Spare Number) / PWA-PL5400D