Re: No Com Port
I just hit this same problem with a brand new Win 7 (sp1) + (all windows update) box built just for managing 3D printer builds,... I was just about to claim that the link above does not solve this...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
I cut the trace from USB 5V but the problem was not solved. Do you guys know why? Can i still try your solution or did I mess it up? Does it have to be Schottky diodes? What spec am I looking for?...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Sure you can still try with the diodes. The Schottky diodes are preferred because they have a low forward voltage. But you can also try with standard diodes, it should still work, as long as the...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
As @enif said, the schottky diodes prevent too much voltage drop across them. Give standard ones a shot if that's what you've got. They don't need to be particularly heavy duty or anything. Low...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
OK. I've got a couple of standard diodes but the forward voltage is about 1V. Is that too much? By "problem not solved" I mean it is still burning hot, even without USB connected. I did cut the trace...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
At the input of the 7805 the forward voltage is no problem at all, since anyway we have to drop ~7V at the linear regulator. With only the USB input, the 1V drop is probably still ok, if the BOD...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
@enif, do you have any thoughts on how changing the voltage might impact the thermistor readings? Since the thermistors are based on a voltage divider down from the 5V bus, would the ADCs read the...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
@maso: As long as the termistors are read while the printer is running (which is the normal case), the diodes do not matter, since then the 5V are coming from the 7805 regulator. On the contrary,...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Yeah, that answers my question. I was wondering if you could read the thermistors with the vUSB - vDIODE = 4V powering it, then apply 12V and, now that a full 5V is being provided, see that thermistor...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
I've found a nice online store to buy the schottky diodes. The BAT42 spec says: voltage drop 0.4V, voltage 30V, current 0.2A. Will it work? What is the maximum current running? I think I will buy a...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
200mA for the 5V rail should in principle(!) be fine. I use BAT43 here (which have the same max. current) without ever having had any problems. BUT if your regulator gets hot, you might have some...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
I haven't measured the current, only voltage. To do it, I have to break the circuit somewhere, right? I can't just touch two points. Edit: I measured in series with the input 12V screw terminal and...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
135mA through the 7805 will roughly give 1W (7V*.135A), so it should not really get that hot... I just measured my Sanguinololu with the stepsticks installed, but with nothing connected: Powered via...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Now without the stepsticks I got 110mA. Then i connected the USB and I got 120mA.
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
When I remove the AtMega644/1284 and the stepsticks, I measure 6mA on the 13.9V input. How much you get? I still wonder if the problem is not due to some short (to GND or 5V) of an output pin of the...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
I don't want to desolder my AtMega chip. Any other way?
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Ooops! Of course not. Mine is removable on a socket... With no power connected, you could try to measure the resistance from all possible output pins (1-8, 14-20, 21-29) to GND and 5V (any why not...
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Ok I'll measure the resistance then. Sorry, what am I looking for? Edit: GND: pin18 and pin19 measured 9.9 something. 5V: pin18 and pin19 measured 10 something 12V: Nothing
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Pins 18/19 are the MOSFET gates, they are connected via 10k to GND. So if it's 9.9/10 kOhm (not Ohm!) then it's normal.
View ArticleRe: My mods for curing 5V USB/7805 problems on Sanguinololu 1.3a
Then how can it get hot? Do you think it will help to buy a new regulator, maybe with other spec.? And could the diode method help?
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