Apologies if this isn't the right place to post this thread but I'm new to the forum
Picked up a Commodore 1084S-D PAL (Model 1084S-D, 240V, March 1990, Made in Korea, Daewoo chassis A-17) for £10. On power-up: badly distorted picture, RGB channels showing as separated wavy coloured outlines, present even with no source connected. Degauss not firing.
Faults found on the main board
- A cap had fallen off the video board entirely (clean pads)
- Bulging 220µF 400V main PSU cap
- Multiple dry/cracked solder joints
- Dried electrolyte leakage around C233/C235 (flaked when picked, board clean underneath, hadn't reached solder side)
- Daewoo glue disease around C233, D216, D219, D245 hardened conductive adhesive across a diode cluster and over the legs of I602, with green corrosion
- Corroded resistor legs in the leakage zone
- Dry joint on PR01 (the degaussing posistor, ERP-Z5BON18
Work done:
- Removed and cleaned the mainboard and neck board. Checked for dry solder joints and repaired
- Full recap with correct kit for the S-D revision; includes the 220µF 400V cap for 240V mains.
- Replaced I602 (Toshiba TC4066BP quad bilateral switch, RGB/composite mode routing) with a Texas Instruments CD4066BE in a 14-pin DIP socket. This was the prime suspect given the corrosion.
- Replaced TDA1670A degauss control IC (dried thermal paste, sat in the contamination zone), re-pasted.
- Resistors: R246 (220Ω ¼W, tested 218Ω but corroded leg), R310 (2.2Ω ½W), R313 (2.4KΩ ¼W the leg snapped, open circuit, in the video path).
Not sure where to go with the troubleshooting next. I'm new to CRTs as i'm more used to restoring old computers so any advice or guidance on what to try next would be massively appreciated!
Thanks!
Mark