SB-028

Repairing DG-5                             2-3-78


1.	Symptoms:  Two dots on LED display
	Check:  Het input and VFO input connections (Dirty, intermittent, missing.)

2.	Display reading wrong frequency
	Check:  If display frequency is reading off by 2 MHz and last four digits on display reading (894.9) check carrier input wire (Dirty, missing, intermittent.)

3.	No display or dim display
	Check:  5v reg (IC power) not working or plated thru holes not plated thru.

Avobe are common mechanical failures that occur with DG-5.  We suggest the following troubleshooting procedure:
	Check:	

		A.	Power all power supply levels.
		B.	Reference oscillator Q21 and divider chain IC5-11 (RF, waveforms, DC.)
		C.	Carrier, VFO and HET, also counter (When applicable) for RF, Waveforms and DC levels; see service manual for proper levels.

	Note:	Operation of the circuits are essential before proceeding.

It's been Kenwoods experience that when problems do occur with the DG-5 that approximately 90% of the problems will be caused by insufficient solder connections and not the actual components themselves.

	Note:	We suggest the following procedure if buffers, mixers and oscillators are working properly:  See service manual for proper levels.

	Check:	
	
		A.	All sloder connections (loose or cold.)
		B.	Solder all plated thru holes:  32 guage wire inserted in plated thru holes takes approximately 30 minutes to do and is very, very, effective.

Service Suggestion:

A heat gun and freeze spray often are very effective in locating cold or not-plated thru holes.

		A.	Heat board with heat gun (expands board).
			This often caused dormant or loose connection to appear.

SB:AR

(c) 2378TKC