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Modifications for the Kenwood DG-1
DG-1 Standard service procedure

It is out experience here in the Compton service facility that the vast majority of DG-1 problems are not component failure, but cold solder connections on the digital PCB (X54-1160-00)

The second most frequent problem is dirty Molex connectors between the 2 PCB's in the DG-1.

Recommended service procedure: Remove both boards. Using a fine point, low wattage iron (less then 45W), and a good quality, low flux content solder, carefully resolder all components. (There are 18 of these points - only one id not top accessible, but is located under IC 11 and can be resoldered from the bottom).
Resolder the Molex connectors. There are 9 print-thru's where solder may not have flowed thru to the component side.

Using a good quality tuner cleaner with silicone lubricant, spray both boards Molex connectors and work the pins in 3 or 4 times to insure good contact. Resembled and final check.

Total time on the bench: 20 minutes. We will allow up to 1 hour only warranty labor time.

DG-1 Standard service procedure

Author: Trio-Kenwood Communication, inc.

Introduction

A majority of DG-1 failures are caused by either dirty connectors, or cold soldered connector pins between the top and bottom foil paths of the double printed board.

Before any component level service is attempted, it is advisable to eliminate the possibility of an intermittent connection causing or complicating Counter failure.

1. Physically disconnect the main power cord!
2. Remove cabinet covers; top with speaker lead, and bottom.
3. Unplug the top and bottom connectors from the DG-1 unit.
4. remove the Digital Unit assembly by removing 4 screws from the chassis underside.
5. Disassemble the Digital Unit; remove 8 screw and slide off the cover.
6. Remove both PC Board, 4 screws each.
7. For those connector pins joining top and bottom foil paths; reheat pin, flow .031" diameter solder from the top to insure the solder joint through the PC Board.
8. Wash the board to board Molex connectors with FRESH triclorethelyne. Heat dry and inspect for flux residue. If necessary, recline. Also remove the pin connectors from the DG-1 chassis, (note they insert from the Digital PC Board side) and clean in FRESH tricolor. Heat dry and spray with silicone lubricant.
   Spray into the board mounted connectors with silicone.
9. Reassemble by reversing step 8,6 and 5.
10. Reinstall by reversing step 4, 3, and 2.

How to solder on the DG-1 board.

1. Use a low power pencil, 35 W or less!
2. Use rosin code solder, small diameter.
3. Do not create solder bridge or splotches.
4. Do not overheat or otherwise lift the foil from the board.
5. Wash excess flux away with FRESH tricloretheylyne and a small flux brush. Neatness counts -- it's YOUR radio.

Note:

1. The best possible method of cleaning the Molex connectors is by ultrasonic cleaner and fresh solvent. Otherwise, use a spray.
2. In extreme cases, replace the Molex connectors, 6 pieces E40-0607-05.
3. For 15 & 10M invalid numbers, such a backward "6", replace D13, D14 SV-03 on the Counter Mix unit X54-1150-00. These are three section diodes (three junctions in one package) V21-0007-05.
4. For random or rolling display which will not correct by cleaning connectors, etc., check the CCR mixer input level. It should be 50mV measured width a high RF VTVM, and can be adjusted by TC-1 on the IF unit X48-1150-00, and measured o the IF TP6. (TS-820S Service Manual states 0.1mV- correct this to 50mV).

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 73's
   John Ribeiro
             KB2LJJ