Hoshizaki 73168 service manual Service Chart, Control Board Alarms EA and ED, No Operation

7. Control Board Alarms (EA and ED)

"EA" is displayed when an EEPROM write error is detected. "ED" is displayed when an EEPROM verification or read error is detected.

Reset Options

Replacing the control board with a functioning control board will eliminate this alarm condition.

B. Service Chart

1. No Operation

Problem		Possible Cause			Remedy
[1]	The unit will not	a)Power Supply	1.	Unplugged, off,	1.	Turn on, replace, or check
	start.			blown fuse, or tripped		and reset. Call electrician if
				or defective circuit		breaker trips repeatedly.
				breaker.
			2. Loose connection.		2. Tighten.
			3. Not within		3. Refer to nameplate and
				specifications.		correct.
		b)Cord and Plug	1.	Defective.	1.	Replace.
		c) Control Switch	1.	"OFF" position.	1.	Move to "ON" position.
			2. Bad contacts.		2. Check for continuity and
						replace.
		d)Transformer	1.	Open coil winding.	1.	Check continuity and
						replace.
		e)Wiring to Control Board	1.	Loose connections or	1.	Check for continuity and
				open.		replace.
		f) Control Board	1.	In alarm.	1.	See "III.A. Alarm Signals."
			2. Defective.		2. Replace.
[2]	Cabinet, rail, or	a)Fan Motor	1.	Motor winding open.	1.	Replace.
	condenser fan will		2. Bearing worn out.		2	Replace.
	not start.
			3. Wiring to fan motor.		3. Check for loose or open
						connection, and replace.
			4. Fan blade bound.		4. Check and replace.
		b)Evaporator Fan, Rail	1.	Bad contacts.	1.	Check for continuity and
		Fan, or Compressor				replace.
		Relay	2. Coil winding open.		2. Replace.
		c) Control Board	1.	Defective.	1.	Replace.
[3]	Compressor will	a)Compressor Relay	1.	Bad contacts.	1.	Check for continuity and
	not start or stops					replace.
	operating.	b) Compressor Control	1.	Bad contacts.	1.	Check for continuity and
		Relay				replace.
			2. Open winding.		2. Replace.
		c) Start Relay	1.	Bad contacts.	1.	Replace.
			2. Coil winding open.		2. Replace.
		d)Start Capacitor	1.	Defective.	1.	Check and replace.
		e)Wiring to Compressor	1.	Loose connection(s).	1.	Tighten.
			2. Faulty.		2. Check continuity and
						replace.

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