AtmelAce
Inactive User
Sorted this for someone last week- only just got round to posting. Reported mute error on card so I thought it was the reader ( common problem). Wasn't that.... Turns out it was a short circuit cap.... which had been suggested( but I ignored it).
There are several caps around reg101( I think that's the reg no.) and I have highlighted the one that was short. The second pic shows the edge of the board so you can see the approximate location.... I have the priveledge of owning a "Toneohmmeter" that I bought 20 years ago. It was designed to pinpoint short circuits on printed circuit boards.... Basically, it works like this:-
It injects a small voltage into two points on a circuit and measures the current flow. This in turn is converted into an audio tone. The closer you get to the short, the higher the tone produced.It is so accurate, you can detect a short to within about 10mm of its location.Certainly helped me find this one. It also found another real bitch of a short... a 4001 came up all 8's. Reflowed the Attys , saw no shorts so got the meter out again.... Turns out the short was inside the atty, pin 45 to ground.No chance of a fix, except remove and replace atty with the correct dump- not worth the effort unless you have the gear.....
P.S.... How did I know the short was inside the ATTY? I lifted the leg on the atty and it was still shorted to ground....
Can't upload the pics....
There are several caps around reg101( I think that's the reg no.) and I have highlighted the one that was short. The second pic shows the edge of the board so you can see the approximate location.... I have the priveledge of owning a "Toneohmmeter" that I bought 20 years ago. It was designed to pinpoint short circuits on printed circuit boards.... Basically, it works like this:-
It injects a small voltage into two points on a circuit and measures the current flow. This in turn is converted into an audio tone. The closer you get to the short, the higher the tone produced.It is so accurate, you can detect a short to within about 10mm of its location.Certainly helped me find this one. It also found another real bitch of a short... a 4001 came up all 8's. Reflowed the Attys , saw no shorts so got the meter out again.... Turns out the short was inside the atty, pin 45 to ground.No chance of a fix, except remove and replace atty with the correct dump- not worth the effort unless you have the gear.....
P.S.... How did I know the short was inside the ATTY? I lifted the leg on the atty and it was still shorted to ground....
Can't upload the pics....
