Modifications for the Kenwood DG-1
Service Note on DG-1
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 solicon lubricant, spray both boards Molex connectors and work the pins in 3 or 4 times to insure good contact. Ressamble and final check.
DG-1 Standard service procedure
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.
- Physically disconnect the main power cord!
- Remove cabinet covers; top with speaker lead, and bottom.
- Unplug the top and bottom connectors from the DG-1 unit.
- remove the Digital Unit assembly by removing 4 screws from the chassis underside.
- Disassemble the Digital Unit; remove 8 screw and slide off the cover.
- Remove both PC Board, 4 screws each.
- 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.
- Wash the board to board Molex connectors with FRESH trichlorethelyne. Heat dry and inspect for flux residue. If necessary, reclean. Also remove the pin connectors from the DG-1 chassis, (note they insort from the Digital PC Board side) and clean in FRESH trichlor. Heat dry and spray with silicone lubricant.
Spray into the board mounted connectors with silicone.
- Reassemble by reversing step 8,6 and 5.
- Reinstall by reversing step 4, 3, and 2.
How to solder on the DG-1 board.
- Use a low power pencil, 35 W or less!
- Use rosin code solder, small diameter.
- Do not create solder bridge or splotches.
- Do not overheat or otherwise lift the foil from the board.
- Wash excess flux away with FRESH trichloretheylyne and a small flux brush. Neatness counts -- it's YOUR radio.
- The best possible methode of cleaning the Molex connectors is by ultrasonic cleaner and fresh solvent. Otherwise, use a spray.
- In sxtreme cases, replace the Molex connectors, 6 pieces E40-0607-05.
- 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.
- For random or rolling display which will not correct by cleaning connectors, etc., check theCCR mixer input level. It should be 50mV meassured width a high RF VTVM, and can bbe adjusted by TC-1 on the IF unit X48-1150-00, and meassured o the IF TP6. (TS-820S Service Manual states 0.1mV- correct this to 50mV).
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