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I draw the line at 20-30 pin packages. Don't even want to think about replacing a 128 pin ARM chip :)
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On Sun, Nov 10, 2024 at 06:25 PM, Brendan wrote:
Yeah Paul has been doing his hand at some G2 ICs R&R and is doing well (another notch in his belt of skills)! David partridge, Michael and I and even others, Losmandy!. ?Many electronic repair places don’t like to touch these as they don’t understand the system or quote the $100+ per hr repair rate nor do they don’t have ICs in stock or access to inbuilt firmware, like dspic33s...and many others.? They couldn't replace the ARM and load in the very specific bootloader (firmware), so the main firmware can be uploaded by SD card and GFU. This is propriety as indeed in reality so is the dspic33 firmware.
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It’s actually not *that* hard using a drag soldering tip (the ones that have a concave end to hold some solder).? I’ve done it myself a few times, and only needed to do a bit of cleanup with solder wick.? You do need lots of liquid flux though or the exercise is doomed to failure. ? D. ?
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From: [email protected] <[email protected]> On Behalf Of Paul Kanevsky
Sent: 11 November 2024 03:44
To: [email protected]
Subject: Re: [Losmandy_users_io] G11G DEC Stall? I draw the line at 20-30 pin packages. Don't even want to think about replacing a 128 pin ARM chip :) On Sun, Nov 10, 2024 at 06:25 PM, Brendan wrote: Yeah Paul has been doing his hand at some G2 ICs R&R and is doing well (another notch in his belt of skills)! David partridge, Michael and I and even others, Losmandy!. ?Many electronic repair places don’t like to touch these as they don’t understand the system or quote the $100+ per hr repair rate nor do they don’t have ICs in stock or access to inbuilt firmware, like dspic33s...and many others.? They couldn't replace the ARM and load in the very specific bootloader (firmware), so the main firmware can be uploaded by SD card and GFU. This is propriety as indeed in reality so is the dspic33 firmware.
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Have to say, drag soldering is an amazingly effective technique. The few SMD chips I replaced previously were always a struggle, and I tried solder paste and soldering individual pins. Drag soldering literally takes less than a minute, requires very little cleanup and produces high quality, good looking joints.?
On Mon, Nov 11, 2024 at 08:31 AM, David C. Partridge wrote:
It’s actually not *that* hard using a drag soldering tip (the ones that have a concave end to hold some solder).? I’ve done it myself a few times, and only needed to do a bit of cleanup with solder wick.? You do need lots of liquid flux though or the exercise is doomed to failure.
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D.
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I draw the line at 20-30 pin packages. Don't even want to think about replacing a 128 pin ARM chip :)
On Sun, Nov 10, 2024 at 06:25 PM, Brendan wrote:
Yeah Paul has been doing his hand at some G2 ICs R&R and is doing well (another notch in his belt of skills)! David partridge, Michael and I and even others, Losmandy!. ?Many electronic repair places don’t like to touch these as they don’t understand the system or quote the $100+ per hr repair rate nor do they don’t have ICs in stock or access to inbuilt firmware, like dspic33s...and many others.? They couldn't replace the ARM and load in the very specific bootloader (firmware), so the main firmware can be uploaded by SD card and GFU. This is propriety as indeed in reality so is the dspic33 firmware.
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On Mon, Nov 11, 2024 at 06:47 AM, Paul Kanevsky wrote:
Have to say, drag soldering is an amazingly effective technique. The few SMD chips I replaced previously were always a struggle, and I tried solder paste and soldering individual pins. Drag soldering literally takes less than a minute, requires very little cleanup and produces high quality, good looking joints.?
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I had been using reflow techniques with a rework station which works perfectly on high density packages. Solder paste works very well where you need to set up many pads for a single device.? ?
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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I’m sure it was just my amateur skills, but all solder paste helped me do is bridge all the pins together in one shot ;) I’m sure a proper stencil would’ve helped, but drag soldering worked first and every subsequent time I tried.
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Regards,
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? -Paul
On Mon, Nov 11, 2024 at 12:38 PM, Chip Louie wrote:
On Mon, Nov 11, 2024 at 06:47 AM, Paul Kanevsky wrote:
Have to say, drag soldering is an amazingly effective technique. The few SMD chips I replaced previously were always a struggle, and I tried solder paste and soldering individual pins. Drag soldering literally takes less than a minute, requires very little cleanup and produces high quality, good looking joints.?
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I had been using reflow techniques with a rework station which works perfectly on high density packages. Solder paste works very well where you need to set up many pads for a single device.? ?
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Chip Louie Chief Daydreamer Imagination Hardware?
Astrospheric Forecast - South Pasadena, CA?
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I never worked on Gemini units, but from my experience I agree with not using solder paste without a stencil. Trying it without stencil only needs much more time applying the paste and then for cleaning up the mess afterwards without any advantage. For small pitch ICs like the approx 25mil SSOP of the FT232 I think drag soldering is the most efficient if not the only possible way of hand soldering. For larger pitch packages like 50mil TQFP or SOIC however I reverted to soldering pin by pin using 0.5mm solder and a cheap stereo microscope or strong glasses. This way with a bit of practice no addl flux and no solder wick is needed. The big advantage is that no significant amount of flux gets underneath the package where it is almost impossible to remove by simlply cleaning with IPA. As some flux residue are becoming hygroscopic over time, having no flux residue on a PCB can be a big advantage if the PCB is used in humid air / outside. I'm not sure whether this is relevant to Gemini units at all, but for battery powered sensors for example flux residue becoming moist can increase sleep current considerably and significantly shorten battery life. Went through this myself...
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Regards,
Stephan
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On Mon, Nov 11, 2024 at 03:47 PM, Stephan G wrote:
The big advantage is that no significant amount of flux gets underneath the package where it is almost impossible to remove by simlply cleaning with IPA. As some flux residue are becoming hygroscopic over time, having no flux residue on a PCB can be a big advantage if the PCB is used in humid air / outside.
I've used a hot air gun (set to the lowest temperature and high velocity) to try to blow the stuff from under the chip, but I suppose some still remained. An ultrasonic cleaner might be a better solution.
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I've seen worse. "Oh look, I can see its?brains." Some politely smoke, others go Krakatoa!?
I continue to be amazed at how little solder is needed to mount?a, say 8 x8 mm?IC. I find if I cut factory SMD paste about 5:1 with flux, nice clean joints form. Another secret is to wick as much of the original solder off as possible. You're never going to get to clean copper, but that's not necessary. Otherwise?you risk bridging.?
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On Wed, Nov 13, 2024 at 01:25 PM, George Cushing wrote:
?Another secret is to wick as much of the original solder off as possible. You're never going to get to clean copper, but that's not necessary. Otherwise you risk bridging.?
Here was my first attempt at Gemini dsPIC33 removal (with Brendan's invaluable help) :)
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Yeah and clean, well organized?workplace.
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On Wed, Nov 13, 2024 at 02:40 PM, George Cushing wrote:
Yeah and clean, well organized?workplace.
How did you get a photo of my desk???
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? ? ? “Yeah and clean, well ? ? ? ? organized workplace.”
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Hahaha I start every job with a clear desk …..end up looking like that. ?Only takes a few hrs!
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George, you use “Dexion storage bins”! ? A tech’s go to for organising!
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Is that Astrophysics HC I see in one of the bins on the right? ?The 855 hot air is like mine. ?I really should get a proper Quick 861DW. ?
Mine is only good for heatshrink and burning my fingers. ? ?Paul did really well and glad it worked out as it gives confidence. ?
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Brendan
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Interesting you're dissatisfied with the 858D. I too have one of those plus additional nozzle. Don't use it for anything really sophisticated but find it quite well suited for the occasional job of removing something of the size of 44pin QFPs or smaller. And for the money saved compared to a proper tool you can pay someone to clean up your desk for years.
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Probably a Chinese copy. Fine them handy for thing I use a lot. Keep electronics?parts and assemblies in this Harbor Freight rack and a couple?of plastic?multi-drawer?storage units on top.?
I get enough use out of the 881 to have burned out heating coil. Second soldering station, the first went through its transformer. The irons last about a year.
No, that's Dave Schwartz' Smart Hand Control (SHC) for OnStep motor controllers. It' built around an Espressif ESP32 development board. Use it to test the MCU modules before?soldering?them on their PCBs. Hate to waste a $2 PCB. The MCUs are fabbed by Taiwan semi, but the modules are assembled in China. At $3 a unit you have to do your own QC. They run about 10% defective. Mostly in the USB circuit. The SHC runs about $10-12 in parts. I sell them as a kit for $25 assembled for $40. The switches don't travel well thus I mount them for shipping.
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Paul Kanevsky
David C. Partridge
Chip Louie