NOTES & ERRATA Low Cost 1GHz Counter (April 1993): When fitted with the High-Resolution Modification of March 1994, the kHz LED may still glow significantly when the MHz ranges are selected. This is due to the output voltage from U2 on the modification board being lower than 5V, causing incomplete switching of the LED driver transistor (Q5). This can be remedied by transferring the connections for the rotors of SW1b and SW1c to switch SW2, instead of to the terminals to the mod PCB. The wire that connects to SW1b goes to the unused contact, while that for SW1c goes to the contact which connects to pin 1 of U2 on the mod PCB.