Hi!Welcome to my DIY audio forum.CheersPer-Anders Sjöström
Started by Keljian, June 13, 2005, 04:54:06 PM
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Quote from: perandersIf it's possible, can you take one or more close up pictures so I can see the parts you have used? (Max 1 MB please.
Quote from: perandersR10? Should be a wire = 0 ohms. Check my picture. I have a wire jumper, that beige thing.
Quote from: perandersDon't change the transistors until you have measured that are broken, I'll doubt that. Do you have 0.6-0.7 volts between the base and the emitter?
QuoteDo you have connection between the feedback R8, R9 and the inverting input of the opamp? R10 = 0 Ohms
Quote from: perandersIf you have 0.7 volts that's good.Do you have the same voltage at pin 2 as over R9? Meening do you really have a wire in R10? On the solderside?
Quote from: perandersAD797 may not like too much differntial voltage. I don't recommend it as you may have noticed, still you can fix this by applying to diodes across the inputs.Would you please measure:Pin 2, 3, 4, 6, 7VoutVinVoltage across T4
Quote from: perandersCould you please measure the opamp voltage with ground as reference.Are you sure you have solder all IC pins with success?Aha, 431, startup problems, I may know what your problem is. The problem may be the feedback of the LM431. I'll come back soon with a solution. The resistor values must be chosen with taste. The problem is when the 431 is inactive, then the ref voltage must be LESS than the feedback from the output. If not you will get a stable hang-up condition.
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