Hi Paul, I checked one of the v8.0 boards and note continuity between the LM7805 output pin hole and pin 8 of U8, the opamp. Please look carefully at the solder joints on pin 3 of the 7805 and pin 8 of U8.
73, Tony KB9YIG ----- Original Message ----- From: Paul Theunissen To: [email protected] Sent: Monday, May 12, 2008 4:51 AM Subject: [softrock40] Softrock Lite+XTALL beta 8.0 Hi All, Last week, just the day I mailed Tony about the shipment of my Lite+XTALL kit I received it. I made some pictures during the build, and some measurements. Posted on http://www.theuno.nl/blog/ (not that fancy). Now I'm at the part of the opamps, and it looks like that they only get between 2.06v and 2.5v on the V+ pin. In the datasheet I see that the voltage should be between 3v and 12v. And I was expecting to measure something around the 5v after reading the schematic, the LM7805AC gives 5v as output. Now with a closer look at the board, I find that R19 (1k Ohm) is between the feeding point for the opamps, and the 5v line. Then it is logical that I measure the 2.5v (with the Si570 working in the lowest frequency). I think that this might not be enough to really drive the opamps. Is this correct ? Or should these work with just around 2v ? Or should some correction be made, or did I overlook something somewhere ? Hope somebody can help me out. Thanks, Paul PD5PT
