Enviable troubleshooting skills on display as usual! Great video. Still makes one wonder why it worked without fault originally. Perhaps the internal circuitry of the chip has become less robust over time, and reducing the "grunt" needed to overcome the higher resistance was what it needed to keep doing its thing consistently. Awesome work! - JRH
Different brands/models of these step-down converters work slightly differently and need set up differently, so possibly they fitted the LT8609 thinking it was 100% compatible with what the original design called for? Interestingly, the LT evaluation board for the LT8609 uses a 1Mohm pullup to VIN on EN, and a 0.22uF on BST. Nice repair though, enjoyed the diagnosis.
Oh, you have an evaluation board with 1M resistor to Vin? So perhaps this was not a mistake on the part of PreSonus, but they followed some recommended design. Well, I am not sure how to interpret this, but it does seem to me that this 1M pullup was the culprit.
@@feedback-loop No, there's a schematic on AD's site of the evaluation board. It could be your IC is partially damaged, but I agree, 1Mohm would seem rather high a pull up!
Awesome repair! A bit disappointing to find low quality caps and bad solder joints since these units are (probably) expensive. Not to mention the bad design.
1M pull-up seems a very odd choice, I can understand a weak pull-up to allow a pin to be pulled low without excess current, but 1M seems like asking for trouble to me.
I wish I could fix things at this level of understanding. Thanks for sharing your thought process. I'm always happy when a new video of yours is published.
Very odd design flaw. Can't really picture in my head how such a failure mode would only start happening over time but I assume this wouldn't be a one off problem with these units.
Nice fix, as usual...congratulations. Like others said, using a pull up resistor equal to 1 M seems a bit strange...such a high value is a good noise generator😅😅😅. Not exactly a desiderable result... Regards from Italy.
Yes, it is a rule. And I checked, but not when the fault manifested itself. And I had a wrong idea that the problem must be with digital part. And I imagined something transient like a bad reset or too much ripple during initialization or something like that. Everything is obvious once you know the answer.
@@feedback-loop Did you test that 1M resistor after you changed it? Just wondering if the value had drifted upwards over time and whilst the circuit coped with 1M it couldn't cope with more than that.
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Great detective work my friend
Enviable troubleshooting skills on display as usual! Great video. Still makes one wonder why it worked without fault originally. Perhaps the internal circuitry of the chip has become less robust over time, and reducing the "grunt" needed to overcome the higher resistance was what it needed to keep doing its thing consistently. Awesome work! - JRH
Different brands/models of these step-down converters work slightly differently and need set up differently, so possibly they fitted the LT8609 thinking it was 100% compatible with what the original design called for?
Interestingly, the LT evaluation board for the LT8609 uses a 1Mohm pullup to VIN on EN, and a 0.22uF on BST.
Nice repair though, enjoyed the diagnosis.
Oh, you have an evaluation board with 1M resistor to Vin? So perhaps this was not a mistake on the part of PreSonus, but they followed some recommended design. Well, I am not sure how to interpret this, but it does seem to me that this 1M pullup was the culprit.
@@feedback-loop No, there's a schematic on AD's site of the evaluation board. It could be your IC is partially damaged, but I agree, 1Mohm would seem rather high a pull up!
I wonder if they populated that resistor with the wrong part, certainly looks like it, nice repair.
Great repair. It is nice to have a slightly longer video from you for a change.
Finally a head scratcher not a fuse repair always worth a watch
Awesome repair!
A bit disappointing to find low quality caps and bad solder joints since these units are (probably) expensive.
Not to mention the bad design.
very nice video :)
It's like Dave says. Thau shall always check voltages :)
1M pull-up seems a very odd choice, I can understand a weak pull-up to allow a pin to be pulled low without excess current, but 1M seems like asking for trouble to me.
Wow! Amazing troubleshooting work!
Excellent repair video!
I wish I could fix things at this level of understanding. Thanks for sharing your thought process. I'm always happy when a new video of yours is published.
Very odd design flaw. Can't really picture in my head how such a failure mode would only start happening over time but I assume this wouldn't be a one off problem with these units.
Nice fix, as usual...congratulations. Like others said, using a pull up resistor equal to 1 M seems a bit strange...such a high value is a good noise generator😅😅😅. Not exactly a desiderable result... Regards from Italy.
Great video !
Сјајно!
Cool
nice video, very versatille
awesome
Isn't it a rule to check all voltages first?
This equipment left better than it came, recaped!
Yes, it is a rule. And I checked, but not when the fault manifested itself. And I had a wrong idea that the problem must be with digital part. And I imagined something transient like a bad reset or too much ripple during initialization or something like that. Everything is obvious once you know the answer.
@@feedback-loop He who knows, knows. And you know a lot.
Very interesting.
Complicated fault
3M ohm, WTF - lol -.
marking is 01E, which is 1 meg
@@feedback-loop So, they used the wrong R, right from the beginning?
I would think so.
@@feedback-loopbut did the device also have this fault from the beginning?
@@feedback-loop Did you test that 1M resistor after you changed it? Just wondering if the value had drifted upwards over time and whilst the circuit coped with 1M it couldn't cope with more than that.
Good fix! Thanks for the Detective work!