When I was very young we used muffle ovens to bake potatoes. And kept beer in precision cooler. It was laboratory of thick film ICs.
Last edited:
Thanks Scott, Thorsten, Fitzfish; I think my hesitation is for heating through the bottom, being afraid that I would toast the whole board.
Maybe I should just try it. And do it first on board, before any of the other parts.
jan
Hi,
With modern SMD stuff and hand assembly IC's go first, not last, the reverse from how we learned it (actives go last).
Ciao T
With modern SMD stuff and hand assembly IC's go first, not last, the reverse from how we learned it (actives go last).
Ciao T
Hi Jan,
Preheat helps a lot. 60c or so with a heat gun, hair dryer, or toaster and use an decent iron. The solder applied to the top side should wick through to the bottom before installing the part. Makes for a good thermal channel so that you don't have to apply too much heat.
This method also works with DFN/QFN parts, though you don't need to pre-apply solder to the board normally for these. They sit flat on the board so there is no gap to fill. The leads on the sides of these packages are a whole different story....
Dave
Preheat helps a lot. 60c or so with a heat gun, hair dryer, or toaster and use an decent iron. The solder applied to the top side should wick through to the bottom before installing the part. Makes for a good thermal channel so that you don't have to apply too much heat.
This method also works with DFN/QFN parts, though you don't need to pre-apply solder to the board normally for these. They sit flat on the board so there is no gap to fill. The leads on the sides of these packages are a whole different story....
Dave
Set the hotplate to 100 deg Celsius and leave the bare PCB sitting on the plate until it reaches equilibrium. See the rework section in AND8211-D Board Level Application Notes for DFN and QFN Packages
Sorry, forgot one important detail. GET YOURSELF A PAIR OF COTTON GLOVES. Burnt fingers are no fun.
John,
Glad to see you could get the image to post.
I spent the day at the funeral of a famous (or at least controversial) physicist!
http://en.wikipedia.org/wiki/Bernard_Cohen_(physicist) Link almost gets you there...
I tried to enter the D.o.D. but they bounced it as uncited!
Not really a good wiki day.
Glad to see you could get the image to post.
I spent the day at the funeral of a famous (or at least controversial) physicist!
http://en.wikipedia.org/wiki/Bernard_Cohen_(physicist) Link almost gets you there...
I tried to enter the D.o.D. but they bounced it as uncited!
Not really a good wiki day.
Last edited:
Ah at last a way to make money with a perpetual motion machine!
The Johnson Motor
Just send them $47!
The Johnson Motor
Just send them $47!
At least his LLE and economic calculations were amusing and eye-openers.
87, quite an age for a nuclear guy to reach.
Nope, just don't claim the input connected to the output and there is no reason not to issue. I figure the guru of this scam, Tom Bearden, is involved somewhere.
Better yet two of the patents have already expired. I don't know if I have the energy to read these but Mr. Bearden also flogs PM by claiming a generator and motor system that would have net energy out but simply does not claim connecting them together.
Last edited:
The circuit put up, was a test run for circuits drawn on my computer in future. The schematic shown is NOT completely accurate and the mosfets in the power supplly buffer are drawn backwards. This is a conceptual schematic, it has never been built, so it can have a number of problems. However, it served as a TEST, and as an example of the ACTUAL COMPLEXITY of even a simple circuit such as the headphone amplifier, in actual design in a product. It also answers how we sometimes use relays in general and how we hook them up, etc. However, DO NOT ATTEMPT TO BUILD this design as shown and expect it to work, unfortunately it won't, and even if the mosfets are properly turned around, this specific circuit has not been built or emulated.
Still, it has useful concepts, perhaps more than I normally show, as how we do things commercially.
Still, it has useful concepts, perhaps more than I normally show, as how we do things commercially.
- Status
- Not open for further replies.