Quote:
Originally Posted by ScottishColin
re #172
This feels like the first positive thing I've replied with for some time.....yes, I do get a nice solid 1.000Mhz @ 47% reading.
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That is good news. The fault you seemed to have, with 8MHz, 4Mhz and 2MHz all present but no 1MHz out even after replacing the chip just seemed impossible and then your confirmation that you had ~2.5V (not 0V or 5V) on pin 7 seemed to suggest that the 1MHz was really there after all.
As to your question about pin 9 - looking at your photos of both sides of the PCB earlier I can see that there is no connection to the pin 9 pad of UG4 so it's not surprising that you read 0V there - there is no voltage on that pad for your meter to read.
What this means is that you actually have the 'bottom' end of your resistor divider going to the wrong place. Move it from the pin 9 pad to the pin 8 pad, and then it will be connected to 0V and you may find you no longer have to do the 'probe short trick' to get the meter to read.
There is a fine distinction to be made between a point which has no voltage on it (pin 9) and a point which is connected to 0V (pin 8). What you need in this case is the one which is connected to a known 0V (that's why I asked you to use that pad, and not pin 9).