Re: +2 crashes upon pressing some keys
Posted: Thu Apr 12, 2018 1:29 am
Some suggestions and hints and tips:
Only the electrolytic capacitors normally need to be changed.
Don't try to desolder the capacitors unless you are an expert and have suitable tools. Instead cut the leads. Then you can heat the solder pad, and use a pair of long noise pliers to gently pull the old wire out. Then clear the hole of solder using a solder sucker / desolder pump or good quality desolder braid. Don't even think about trying to use cheap stuff.
The advice about taking photos of each capacitor before starting work is an excellent tip that I recommend.
Polarity is very important with electrolytic capacitors. The negative lead is next to the side of the capacitor marked with - signs (radial types). But most circuit board markings use + signs to indicate where the positive lead goes.
Silicon heatsink paste is recommended. The adhesive type was not used when they were manufactured.
It's always a good idea to clean the old heatsink paste off and then apply a thin smear over the surface of the chip and the heatsink before reassembling. You only need a thin smear, as the idea is to fill in any unevenness in the surface, NOT to form a sandwich filling!
With the ULA, the metal heatsink parts fit together in such a way, that they are supposed to securely stay in place. You may however have to adjust the parts, or in some cases, bend the clip very slightly.
Have you ran a simple BASIC program (that shows that it is running, say by printing a counter on screen) for one or two hours?
A dry solder joint can also appear to be a heat related fault. Especially if physical disturbance of the PCB effects the operation.
Mark
Only the electrolytic capacitors normally need to be changed.
Don't try to desolder the capacitors unless you are an expert and have suitable tools. Instead cut the leads. Then you can heat the solder pad, and use a pair of long noise pliers to gently pull the old wire out. Then clear the hole of solder using a solder sucker / desolder pump or good quality desolder braid. Don't even think about trying to use cheap stuff.
The advice about taking photos of each capacitor before starting work is an excellent tip that I recommend.
Polarity is very important with electrolytic capacitors. The negative lead is next to the side of the capacitor marked with - signs (radial types). But most circuit board markings use + signs to indicate where the positive lead goes.
Silicon heatsink paste is recommended. The adhesive type was not used when they were manufactured.
It's always a good idea to clean the old heatsink paste off and then apply a thin smear over the surface of the chip and the heatsink before reassembling. You only need a thin smear, as the idea is to fill in any unevenness in the surface, NOT to form a sandwich filling!
With the ULA, the metal heatsink parts fit together in such a way, that they are supposed to securely stay in place. You may however have to adjust the parts, or in some cases, bend the clip very slightly.
Have you ran a simple BASIC program (that shows that it is running, say by printing a counter on screen) for one or two hours?
A dry solder joint can also appear to be a heat related fault. Especially if physical disturbance of the PCB effects the operation.
Mark