HP Pro 4300 C9H70UT C9H70UT#ABA manual Power-on defect or blank display

Table 38. Power-on defect or blank display (continued)

Problem	Action
The fan works, but the control-panel display is	1. Print an engine test. “Engine test page” on page 254
blank.	2. If the engine test is successful, perform the following
	steps in order.
	● Reseat the control panel and formatter connector. See
	“Control-panel assembly” on page 157 and “Formatter
	assembly” on page 161.
	● Replace the control panel cable. See “Control-panel
	assembly” on page 157.
	● Replace the control panel assembly. See
	“Control-panel assembly” on page 157.
	● Replace the firmware DIMM. See “Firmware DIMM” on
	page 160.
	● Replace the formatter. See “Formatter assembly” on
	page 161.
	3. If the engine test is not successful, remove the
	formatter and attempt to perform the engine test again. If
	the engine test is successful with the formatter removed,
	replace the formatter. See “Formatter assembly” on
	page 161. If the test is not successful with the formatter
	removed, replace the DC controller PCA. See
	“DC controller PCA” on page 181.

238 Troubleshooting Q2431-90912