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http://www.emcloned.com/viewtopic.php?f=24&t=283&p=6293&hilit=702#p6293
1) The right side of R22 15K resistor (connected to uA726 pin 1) is tied directly to ground via the link that is physically located between IC1 (CA1458) and IC2 (LM301A).
2) The trace that joins pin 2 of the uA726, the 1K R23 resistor, D1 anode, 100K R27 and pin 3 of IC3 CA3140 does not connect to ground.
3) The "820 MF" (820 ohm metal film, I presume) resistor that is in parallel with the 1K MF resistor to ground on the right side of R22 15K on the schematic is missing from both the BOM and the PCB. 1K and 820 ohm in parallel like that should make about a 450 ohm resistance.
Assuming the schematic is correct (which seems highly likely for 1 and 2 above, and reasonable for 3 as well) I made corrections to my PCB to match the schematic and tested again. I saw no change in behaviour (0V on the right side of the R22 15K). I desoldered the right left of the R22 15K resistor and it measured it and it tracked the IC1A output perfectly. I resoldered it in place and desoldered the R23 1K and the 820 ohm resistors and measured again - still 0V. I removed the BC547s I was using in place of a uA726 and the voltage then tracked IC1A output just fine. I resoldered the R23 1K and 820 ohm resistors and it once again measured 0V. So if either the resistors, or the "uA726" are in place, then I do not see a voltage going in to pin 1 of uA726.
Just in case my understanding is incorrect I tried measuring the current flowing out of uA726 pin 4 (I believe the transistor pair is a voltage to current converter which drives the actual oscillator circuit itself?) There was no current flow in any of my test cases.
So I am stumped for now. Does anyone have any suggestions? No-one has reported a successful build here or on muffs that I can see.
Damir, what is the status of your builds? Do they work, and if so, did you have to make any corrections like mine?
I already know about the CV width adjustment fix on rev1 boards here: but I do not be