All, I recently built the ICD based on Patrick Touzet's schematics, and am having the "Incorrect MCLR high voltage problem". I read thru the archives and tried various suggestions without success. Here are the details. 1. The ICD is able to program the target board fine. 2. I seem to be getting 13.5 volts on VPP and 5 volt VDD 3. In the options window, it shows VDD as 6.4 V and VPP as 21.8 V, but when I measure the voltage at the header they are about 5.0 and 13 Volts. 4. As per the archive messages I tried putting in a 47 ohm resistor on the cathode leg of the power LED, after which the voltages read 2.8 and 7.0 volt and I get incorrect MCLR low voltage. a 33 ohm resistor gives me MCLR voltage high. In MPLAB the message I get is "Debug module is not exist" "Incorrect MCLR high voltage check ICD p0x764" but it does programn the target chip right and I verified that the target chip's MCLR is tied to 5 volts thru a 10K resistor and that VPP is directly connected to MCLR. I will try a pot tonight to see if it helps but I am wondering if anyone has any other suggestions. Thanks Jay -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu