T870A IR help

[KrInEn]

I just got my T870A IR station from Dragon Soul on Ebay.

http://cgi.ebay.com/T-870A-BGA-IRDA-Xbox-Solution-RRD-YLD-T870-Ps3-Infrared_W0QQitemZ370308965605QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item56382264e5

This is my first run with IR, I was using hot air but this is a much different beast. I am Looking for a good IR reflow profile. what do you set your underheater to? I was just setting mine to 150C then watching my own thermocouple till it hit about 170C for 15-20 seconds then off. Does that sound right? Any help would do!

[ReverseAffect]

185c for 2 mins(from startup to off bottom heater) then shut down bottom heater (i let mine after this idle at 80C).
then start the top IR out at like 250c so it's a pulsating effect before a full blast for a part pull.(that's auto on most ir machines).
but just because the machines are the same model doesn't mean all are the same settings...
it's best to be tuned(profiled) by you working with it..but keep the setting of 250c...
so it's up to you to know the time requirments for a pull...


P.S it's bluedragonchina and hes a awesome honest seller for what he sells in this subject...

[KrInEn]

Ok cool, how about a profile for just a reflow and not a pull?

Thank you!

[ReverseAffect]

well as you know it wouldn't be wise to just reflow the board with this machine but good for a sb,hana,ram,cpu or GPU same  profile settings...(after a few you will see what i mean...main things;timing, temp check along the way and jotting down your progress..
I use a hotair station and a digital temp gun and KESTER 951 flux if i am doing a full top or bottom reflow..
and the bigger machines for a single or surrounding area reflow ....

[KrInEn]

Ah, so it is not wise to just reflow lets say the GPU with the IR. I have a Aoyue 968 as well, but have not found a good reflow profile that keeps the boards going for more than 2 months. I am also using a flux from MGM Electronics, I flux under the chip that I am working on and let it dry for about 20 mins, then I reflow that area (usually the GPU).

If you have a good profile for the hot air stations that would be much appreciated as well. Also I am seeing alot about these "nets" installed in the nozzles. Are these actually worth getting new nozzles for?

[ReverseAffect]

Ah, so it is not wise to just reflow lets say the GPU with the IR.

yes it is wise..i said not the whole board because of moving it around while on a ir is senseless  ...lol
and nets? you lost me, i use just straight through nozzle attachments along with clean flux not paste...
hot air, i set my machines the same temps minus the bottom heater of course digital readout hot air station,
 or portable gun with temp settings and air flow fan speed...
but i use a frame to lock the board down for less temporary heatup warp..
so bottom line is experiential what way is best for you now that you have the basics...

[KrInEn]

Ok got it. Does this sound about right to you for a GPU reflow?

Right now I am preheating the bottom of the board to about 80C once it hits 80 I flip on the IR on the "lowest" setting on the adjusting knob. I also have the IR set to "200C", I let it climb slowly watching my 3rd party thermocouple (seems the included ones are very inaccurate) that is placed on top of the GPU. I let it climb to 180C and I hover there for about 10 seconds and then turn off the IR and let it slowly cool down with the preheater and then I flip that off.

Please let me know if I am way off base.

[KrInEn]

Ok I am in need of some help. I am going to try to clarify this as much as I can.

I have a T-870A IR station. The station has 2 built in thermocouples. One that I use on the bottom side of the motherboard and one that I use on top of the chip (on the green part)

I also have a Nicety DT804 dual type K thermocouple. This I use as a 3rd party to check the temps that the built in thermocouples are reading.
http://www.meter-depot.com/thermometerdt804a.htm

Now for the dilemma. I know that 180-190C is ideal for xbox GPU as top temp. Although I was also told to go up to the point where you can lift the chip and not go any higher. Well I can lift the chip at 190C according to the top thermocouple (one on top of the chip, this is the one built in to the machine). When the built in temp says 190C my 3rd party says 214ish! Now when I do this I usually get a 0102 error after cool down.

Before I was going up to 190C according to my 3rd party and the machines were working. Issue is that the machine temp reads around 150C and the chip does not budge at this temp. Now I understand that they are working, but it would lead me to believe that they are not getting a full proper reflow at this temp.

I would assume that the top way is correct, just maybe the board is cooling too rapidly when I shut off the IR bulb. I am at a loss and I have no idea what to do. I don't want 100's of these things to come back.

[ReverseAffect]

215c-245c is the melting temp ...your stock one is needs to be Re-calibrated....
believe me i have done over 600 of these units and not one lets up under 200c

[KrInEn]

Right, I know the melting temps. I was told that with IR it is different as it is direct heat. Also when my machine says 190C my 3rd party says about 215C, but every time I go that high I end up with a 0102 at the end of it.

Sorry for all of the questions, I just want to get this right sooner or later lol.

btw I am trying to reflow, not reball. Just wanted to clarify that as well.

[ReverseAffect]

yes i know it's direct heat(ir or hot air a temp is a temp)...but the point of my posting still relays on them temps for a good reflow
 definition of a good reflow is good clean flux and heating up solder to the melting point....
don't know about your error ..i am talking about temps not errors...
I don't know what else to tell ya

[KrInEn]

Ok lets say for argument sake that I am getting to the right temps when my Nicety says 215C. Now after I hover there for about 10-15 seconds I turn off the IR bulb and the temp plummets about 20-30C instantly. Would this be causing cold joints? How do I go about gradually letting the temp down where I don't run into these issues. Also about the flux, is it really important to let the flux dry for 30 minutes before preforming the reflow process?

[ReverseAffect]

i don't turn the ir light off, i decrease the temps going down slowly after every 60 sec count to about 180c then shut the ir light off...
(it's not a good thing to just shut the ir light off for the machines and dark ir bulbs sake)
i use KESTER 951 and it's instant for reflows(squirt it under the chip with a eye dropper).
when i pull chips i use a paste flux(AMTECH type:RMA-223)..squirt it around and under the chip...
I don't know where you got your info on waiting for the flux to dry..lol
flux isn't for that purpose....
even when i use a good flux some chips lift or reflow(float) at 200c-245c...lead free melting temps...
now i am done here as said i did tell you everything i know.
i think you have me mixed up with a noob re-baller and re-flow person...lol.....
it took me 3 boards to find a sweet spot on my machines...

[KrInEn]

I apologize, I was not trying to insult you. If anything I am the noob with the IR station. I am just trying to figure it all out. Thank you for straightening out the flux issue for me, seems I was wasting a lot of time waiting for it to "dry" lol. I am going to play around with your initial profile that you posted and see if I can make that work for me. Now the trick is trying to get the bottom heater to go up to 180C it seems that mine heats very very slowly. about 15 mins to hit 100C

[ReverseAffect]

well a good profile is 165c bottom heater let it get up to that and heat for about 2-5 mins..you will see the board starting to lift in some cases....shut the pre-heat bottom off and start the top

maybe your error was caused by to much flux and causing the chip to float and shift,seen this happen many times...

weird as i use a 360 support and heat the bottom using 180c profile because of the support to heater clearance 3/4 of and inch gap
so this gives me leeway for the true 160c-165c bottom preheat..(i see the support that came with yours.it should be the same gap).
and not a problem helping you just pm me anytime my friend...

P.S still freaks me out on them bottom warming times...100c in 15 mins
most of my machines do that in 10min or less ....
but not a problem maybe the housing on the bottom heater is thicker ,which to me looks like it, so not to really worry there...