If you have a multimeter, you can test the earthing by unplugging the computer. Switch to a low resistance range or continuity range on the meter.
Now connect one meter lead to the earth pin on the 13A mains plug. Then touch the other meter probe to each exposed metal ground part on each connector (analogue/joystick port, RF/UHF TV output, BNC Composite Video). Also to any exposed metalwork of the PSU/rear metal panel.
If you get continuity (less than five ohms), it's all okay.
X2 capacitors wear out over time and hence become less effective at doing their job, which is to reduce the amount of interference escaping from the switch mode power supply. Even if they have not exploded, they may be life expired. Especially if they are more than twenty years old.
Normal ribbon cables are rather good at leaking and radiating interference, especially when connected to a microprocessor bus (which is what the 1MHz port is). If anything, having nothing connected to the end is worse!
I suspect from what you say, it's a combination of things that are contributing to the overall poor electromagnet environment. A bit like trying to hold a conversation in a noisy place, then just an extra bit of noise means you can no longer understand the conversation...
Yes, do try plugging into a different mains outlet/socket.
Sometimes a battery operated AM radio that is not tuned in to a station can help work out where the interference is coming from.
Mark
Now connect one meter lead to the earth pin on the 13A mains plug. Then touch the other meter probe to each exposed metal ground part on each connector (analogue/joystick port, RF/UHF TV output, BNC Composite Video). Also to any exposed metalwork of the PSU/rear metal panel.
If you get continuity (less than five ohms), it's all okay.
X2 capacitors wear out over time and hence become less effective at doing their job, which is to reduce the amount of interference escaping from the switch mode power supply. Even if they have not exploded, they may be life expired. Especially if they are more than twenty years old.
Normal ribbon cables are rather good at leaking and radiating interference, especially when connected to a microprocessor bus (which is what the 1MHz port is). If anything, having nothing connected to the end is worse!
I suspect from what you say, it's a combination of things that are contributing to the overall poor electromagnet environment. A bit like trying to hold a conversation in a noisy place, then just an extra bit of noise means you can no longer understand the conversation...
Yes, do try plugging into a different mains outlet/socket.
Sometimes a battery operated AM radio that is not tuned in to a station can help work out where the interference is coming from.
Mark
Statistics: Posted by 1024MAK — Mon Jul 29, 2024 2:10 pm