- Jan 5, 2018
- Jan 5, 2018
This is an attempt to trace a GND Cct. through a cube of interconnected pcb's from the Denon AVR-1912. The reason for this strategy is to enable access to the salient test points on those pcb's. In particular I have lost the GND continuity which is essential to firing up the various IC's on these boards. Therefore the AVR doesn't work. This particular GND Cct. is that which starts at Page111/D10 of the downloadable Denon AVR-1912 Service Manual. Being able to enlarge this on the computer monitor and use the tool 'Ctrl+F' to search for any component in the device and find that component has been high-lighted in Blue is a tremendous help. Every Schematic and Printed Wiring Board for the AVR has reference points - like the 'X' and 'Y' for a graph - on each page - hence being able to refer to Page111/D10 immediately you find CN13A connector. So this trace is starting from pin4 on CN13A and one of the two DVM probes is attached to it. This is 'AGND'. I soon land up in a quandary of a collection of resistors - all seemingly wired together - on Page114/K5. Here is the problem: I have found (through utilising Ctrl+F) each or these 6 resistors and have heard the 'beep' from the dvm. However, getting any further is a problem. It would appear that AGND goes immediately to Page114/O3-4 (CN401) but it doesn't arrive. Neither does it arrive at P114/J5 - C823 and C825 which, according to the Cct.Diag. are clearly on the AV_B'D yet physically (according to Ctrl+F) are on the HDMI_B'D - and so they are in fact. But AGND is not there as per the dvm. So here's a question I must ask: When, in a Cct.Diag. a gaggle of 6 resistors are grouped and connected to a green GND path, are any paths which CROSS another green GND path actually electrically connected? If so that gaggle of 6 resistors makes no sense! Michael Studio1 UK 13:41BST 06-06-2016.