Swapping chip on hot tub motherboard.

[blufx]

Hey guys,
I'm replacing the motherboard on the hot tub. The board I bought is identical except for the controller chip. I'm not well equipped and don't want to damage the chip, or the other board. Rather than attempt de-soldering both chips from the boards, I was thinking about shearing the legs on the chip I want to use close the board, then shear them close to the chip itself on the other one. Make sure everything is clean, and solder the legs to legs. Is there any reason this won't work? The chip with the white label is the one I need to put on the other board.

[diif]

Re: Swapping chip on hot tub motherboard.

If everything else is identical, it's possible the chips was changed for a compatible one and the code/function is the same.
Your method is not one I'd do for fear of damaging the chip through either vibration or heat when you solder the legs.

[R_J]

Re: Swapping chip on hot tub motherboard.

It might work but too much heat on the pins that are left in the board and they will start moving around as the solder melts

[blufx]

Re: Swapping chip on hot tub motherboard.

If everything else is identical, it's possible the chips was changed for a compatible one and the code/function is the same.

My tub has a single two speed pump. The other tub had two single speed pumps. Exactly the same board with different cycle instructions.
Thanks for your reply. I intend to reply to R_J also, but later. I'm tired.

[stj]

Re: Swapping chip on hot tub motherboard.

what's wrong with the old board?

[blufx]

Re: Swapping chip on hot tub motherboard.

what's wrong with the old board?

The relays are corroded. It was subjected to weather for years.

[blufx]

Re: Swapping chip on hot tub motherboard.

It might work but too much heat on the pins that are left in the board and they will start moving around as the solder melts

I'm trying to dream up a method of holding all in place. I might have to resort to some redneck engineering. I'm picturing only a couple or few seconds per leg solder time.
Because nobody likes my piggyback idea, I'm also thinking of a way to apply an upward pull on the chip while I warm it on the opposite side with a heat gun.

[stj]

Re: Swapping chip on hot tub motherboard.

it would be safer to replace the relays than risk the microcontroller.

[blufx]

Re: Swapping chip on hot tub motherboard.

it would be safer to replace the relays than risk the microcontroller.

Thank you, but I'm going to disagree. There are six relays very heavily soldered in place.

[stj]

Re: Swapping chip on hot tub motherboard.

nothing a desoldering pump or good braid wont lift.

[blufx]

Re: Swapping chip on hot tub motherboard.

nothing a desoldering pump or good braid wont lift.

Thanks, but I'm going to stick with replacing the chip on a board that I know works.

[R_J]

Re: Swapping chip on hot tub motherboard.

Take it to an electronic repair shop and have them swap the ic's, should be easy only 18 pins.

[budm]

Re: Swapping chip on hot tub motherboard.

You may want to install good IC socket in the board you want to use that removed IC in case the removed IC is not good or damaged during removal.

[blufx]

Re: Swapping chip on hot tub motherboard.

I want to thank everyone for their input and advice. I scrapped my piggyback idea and devised a spring loaded puller to aid me while heating the other side. I mounted it in a hobby vice where I could view it edgewise. I started applying heat and in no time started watching the legs slowly sink into the board. The last couple of legs got bent a little because it wasn't pulled straight up, but no big deal. My redneck chip puller might look a little crude, but I only spent ten minutes making it, and it worked!

[diif]

Re: Swapping chip on hot tub motherboard.

Good job, I like your puller.

[sam_sam_sam]

Re: Swapping chip on hot tub motherboard.

I will have to keep this in mind when I need to pull out a IC chip like that thanks for sharing your idea

[Longbow]

Re: Swapping chip on hot tub motherboard.

I must have missed something here. I see that the manufacturer has about 10 different versions of this controller board, and it doesn't seem productive to start guessing at what each one does or does not do. Did I miss the part about why this controller chip is thought to be faulty? Working or not, I wouldn't expect rusty relays to operate even with correct coil voltages. Are the relays getting proper coil voltages to turn on? Given the purpose of the board, the heavy duty motor and heater relays and related circuits are the place to start. Car with flat tyre: change the oil dipstick.

[stj]

Re: Swapping chip on hot tub motherboard.

you could just buy a chip-puller.
they are like an oversize pair of tweezers with the ends turned in at 90'
http://www.ebay.co.uk/itm/281224550607

[blufx]

Re: Swapping chip on hot tub motherboard.

you could just buy a chip-puller.

Why? those are generally used to pull a chip from a socket. I'd be willing to bet they would be too thick to get under the IC I was removing. I had to search for something thin enough to get under it and still be strong enough for the job. Plus, I didn't have to wait ten days for it to be delivered.

[stj]

Re: Swapping chip on hot tub motherboard.

i meant for other people.