I have a few questions about some test gear I am trying to fix. There are a couple of one-watt carbon resistors that I am unsure about. One has what looks like a overheating burn on it. It is color coded Beige?,brn,blk and gold. It measures at 8.0 ohms out of circuit. Is that correct? Can a resistor go up or down in value by just a little bit? Can a carbon resistor ever short? The other resistor is marked Red, Red, Gold, Gold, and the last band I can't make out. It measures 3.7ohms. I think it should be 2.2?? Could it possibly have gone from 2.2 to 3.7ohms from overheating? Or did I just read the bands wrong. Is that enough to worry about?
And: This unit is microprosser controled. When it first turns on it boots fine but then it keeps rebooting. I can get it to work by pusing some buttons and kind of distracting it and it will be ok, but if something is rebooting what would you check? It is using a NSC800N-1 40 pin uP and has a 27C64 ROM chip as memory. Can I get some clues on the rebooting by checking pins on these chips. The voltage is stable at 5VDC, what else would cause the uP to reboot? Is it looking for a high or low that might not be there?
Thanks for the help.
Russ
And: This unit is microprosser controled. When it first turns on it boots fine but then it keeps rebooting. I can get it to work by pusing some buttons and kind of distracting it and it will be ok, but if something is rebooting what would you check? It is using a NSC800N-1 40 pin uP and has a 27C64 ROM chip as memory. Can I get some clues on the rebooting by checking pins on these chips. The voltage is stable at 5VDC, what else would cause the uP to reboot? Is it looking for a high or low that might not be there?
Thanks for the help.
Russ