I have triple checked all bjt´s polarities and find no errors... Anyway I think it would be very difficult because I populated first the 327 in both boards, compared them and then populated the 337.
I believe the measurements would not be so good if one polarity was incorrect.
I will replace Q50, R5 and R46 and report back.
Using the trimmer in R8, there is a point wen the trimmer is around 1k5r so total resistance would e 111r, where values over the 200k R45 and R46 get near 1 volt and output swings between -1 and +1V
if I reduce R8 further, output stabilizes at -13.3v... if not using the trimmer, output is +13.3v
So there is a point where everything should be perfect if there was no oscilation.
if I reduce R8 further, output stabilizes at -13.3v... if not using the trimmer, output is +13.3v
So there is a point where everything should be perfect if there was no oscilation.
Maybe the transistors in the mirror have too high Hfe, so reducing all emitter resistors could help.
What Hfe did you use ?
What Hfe did you use ?
Yes I saw that. Many thanks for re-posting! However, it is Valentine's day today and I need to take care of her tonight ;-), so this may take some time
That is very similar to what I saw. But I did have a fair amount of high frequency stuff going on. Do you have a scope that you can use to check if you have RF oscillations?
No scope here 🙁
How did you solve it ?
I did the GND spine as per your foto but nothing changed
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All,
Is there any one that has a LTspice file of the complete (and current) preamp, I would like to try if it is possible to recreate the problem that you are facing using LTspice.
Frans.
Are they reading my post, this is the best duplication (in function) of the 'Area 51' circuit I have seen to date. And it is brand new. When will they start the (my) first payments, soon I guess 🙂
LT4363 - High Voltage Surge Stopper with Current Limit - Linear Technology
LT4363 - High Voltage Surge Stopper with Current Limit - Linear Technology