TheMightyMadman
Active member
Hi all,
I've recently got my hands on three compact Macs - a Classic and two Classic IIs.
I've got the Classic and one of the Classic IIs working well, which is great.
However, the other Classic II is putting up a fight.
Not only is the digital board not working (recapped but needs a new CPU due to corrosion), the analogue board is also faulty.
It was originally completely dead, having suffered from extremely bad capacitor leakage.
Since then, I have:
I replaced DF1 (1N4001) and DF2 (1N4148) in case there was also an issue with the vertical deflection circuit, but I suspect that this is due to the weird low-voltage supply rails; RF7 (3.3 Ohm fusible resistor) tests OK; TEA2037A has been socketed and cleaned but I don't currently have any spares.
Even though this will probably end up as a parts machine, I'd like to get it working.
Has anyone had similar symptoms, and if so did you manage to fix it? Thanks!
Many thanks,
Adam
I've recently got my hands on three compact Macs - a Classic and two Classic IIs.
I've got the Classic and one of the Classic IIs working well, which is great.
However, the other Classic II is putting up a fight.
Not only is the digital board not working (recapped but needs a new CPU due to corrosion), the analogue board is also faulty.
It was originally completely dead, having suffered from extremely bad capacitor leakage.
Since then, I have:
- Replaced all of the electrolytic capacitors (except for the mains filter capacitor).
- Replaced the two RIFA-type mains filter capacitors.
- Checked power switch, fuse, and IEC connector joints - all OK.
- Replaced several parts that had been affected by leaked electrolyte:
- DP6 (MBR1045 Shottky diode), which was badly corroded.
- DP3 and DP4 (1N4148s).
- TDA4605 (PSU driver IC).
- CNY17G (optocoupler).
- QP2 IRFBC40 (output transistor).
- Desoldered and cleaned underneath most major parts, including mains transformer, flyback transformer, connectors, etc.
I replaced DF1 (1N4001) and DF2 (1N4148) in case there was also an issue with the vertical deflection circuit, but I suspect that this is due to the weird low-voltage supply rails; RF7 (3.3 Ohm fusible resistor) tests OK; TEA2037A has been socketed and cleaned but I don't currently have any spares.
Even though this will probably end up as a parts machine, I'd like to get it working.
Has anyone had similar symptoms, and if so did you manage to fix it? Thanks!
Many thanks,
Adam