pre-heater - GSM-Forum

Kytan666 · 02-26-2011, 10:26

i'm having a lot of trouble working with hotair on phone boards, the heat it's lost very fast in the whole pcb , i have a lukey 852D+, i try to work around 350 celsius, but it would take 5 minutes to be able to extract a keyboard driver for example. to work faster i have to boost the temp up to 400 celsius , but mostly i cook the pcb instead of repair.
first what are the recommended temperatures to work with hot air, and second does someone use a preheater ? i made some experiments with 10W power resistors and managed to heat the board to about 90-100 celsius and found that i can work more easy around 370 celsius. but it still take too long .

**.:SARCAR:.** · 02-26-2011, 10:58

mate for rework with hotair in leed pcb u need maximum 200-225^ celcius . & for leed free pcb u need maximum 300-315^ celcius.
but in ur case u use near about 400^ celcius , thatswhy it tost pcb.

using a preheater is better way to rework more faster , because it's heat pcb from underside.

better to search in this forum , u'll find lots of demos or video here.

Kytan666 · 02-26-2011, 12:10

the problem is that at 350 celsius i can heat the board for 3-5 minutes an i'm unable to lift the ic. Is my station defective ? the air temperature seems to be correct , measured with a multimeter thermocuple at the nozzle output..
yesterday i tried to replace a keyboard filter on an e51 , and heated the board at 370 celsius for over a minute and still been unable to lift the ic , after over 3 minutes i lifted the ic but it came with 3 pads from board .. ONE minute at 370 celsius seems death for almost all IC's ..

where is the problem ? is my station deffective? the air flow is little under middle.

gbluez · 02-26-2011, 14:00

hi,
on replacing some broken part, NEVER care about the part that you're going to lift up, and you even can destroy it as well.

your main mission is to replace it, your concern is the PCB.
remove safely emifes by hot solder tip, with some tin leaded on the edge's solder tip.

40 watt soldering iron is enough, not more than 40 second all done

BR

Angello · 02-26-2011, 16:45

Quote:

Originally Posted by Kytan666

i'm having a lot of trouble working with hotair on phone boards, the heat it's lost very fast in the whole pcb , i have a lukey 852D+, i try to work around 350 celsius, but it would take 5 minutes to be able to extract a keyboard driver for example. to work faster i have to boost the temp up to 400 celsius , but mostly i cook the pcb instead of repair.
first what are the recommended temperatures to work with hot air, and second does someone use a preheater ? i made some experiments with 10W power resistors and managed to heat the board to about 90-100 celsius and found that i can work more easy around 370 celsius. but it still take too long .

same problem to me when i want remove connector of i don't have patience to wait 5 minutes and i'm a crazy i use 480°C 5 secondes and i remove connector.

I think the must is to use preUJIheater if you have money LOL.

Kytan666 · 02-26-2011, 21:18

ok ill make a preheater, but i see a lot other people(mostly youtube videos) working with only hot air and working very fast .. where-s the problem ? today i almost cook't a K810 board trying to replace the joystick, and when i got bored heating with 370 celsius and only melting the plastic stick i boosted to 400 and removed but with a pad , 400 celsius and still not all the solder was melted ? ??????? . i use good flux, i have tryied without flux.. same results ..

i noticed a difference on boards, for example old siemens / philips boards work great at 350 celsius , but on nokia boards only chance to remove something with hot air is at 390 celsius witch is extreme.....

..::SuB::.. · 02-26-2011, 21:59

use good solder flux. with this you will work faster and safer. Apply some flux to the joystick's soldered pins and than heat at max. 350 celsius. maybe you have to use more air, but not much because it can damage the pcb too.

EDIT: and also you need to waith 2-3 minutes after turn on the hot air gun because it need time to reach the configured temperature. Expensive solder stations work much faster, but these cost are about 400$.

gbluez · 02-26-2011, 22:00

put some leaded tin with soldering iron around the solder pad before you going to lift up some part. it will soften it. lower temperature of hot air will do the job smoothly.

if you do rework with lead free materials, component soldering temperature specifications
must be strictly obeyed. it's a high risk, 400' C long time exposure is crazy.

just make it leaded, forget about those ROHS things.

02-26-2011, 10:26	#1 (permalink)
Kytan666 Freak Poster Join Date: Sep 2009 Location: Iasi , Romania Age: 40 Posts: 99 Member: 1119968 Status: Offline Thanks Meter: 10	pre-heater i'm having a lot of trouble working with hotair on phone boards, the heat it's lost very fast in the whole pcb , i have a lukey 852D+, i try to work around 350 celsius, but it would take 5 minutes to be able to extract a keyboard driver for example. to work faster i have to boost the temp up to 400 celsius , but mostly i cook the pcb instead of repair. first what are the recommended temperatures to work with hot air, and second does someone use a preheater ? i made some experiments with 10W power resistors and managed to heat the board to about 90-100 celsius and found that i can work more easy around 370 celsius. but it still take too long .

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
FlashTONE Pro v1.01 - Pre-release version	Ice Dragon	Nokia Legacy Phones ( DCT-1 ,2 ,3 ,L )	24	04-05-2002 09:35
Converting 3210 to pre-pay	Dee	Off Topic Zone	2	03-12-2002 18:11
anyone that knows how to program a pre paid sim card and program more minutes into it	abercrombie5464	Hardware Equipments for GSM	3	01-26-2002 02:38
Can't Use Pre-paid cards with Ericsson 768	RB	Old Ericsson Phones & Sony Phones	0	01-04-2000 16:05

02-26-2011, 10:58	#2 (permalink)
.:SARCAR:. Moderator Join Date: Jul 2006 Location: Midnapore,West-Bengal,India Posts: 5,402 Member: 322206 Status: Offline Sonork: 100.1594813/.:SARCAR:. Thanks Meter: 1,350	mate for rework with hotair in leed pcb u need maximum 200-225^ celcius . & for leed free pcb u need maximum 300-315^ celcius. but in ur case u use near about 400^ celcius , thatswhy it tost pcb. using a preheater is better way to rework more faster , because it's heat pcb from underside. better to search in this forum , u'll find lots of demos or video here.

02-26-2011, 12:10	#3 (permalink)
Kytan666 Freak Poster Join Date: Sep 2009 Location: Iasi , Romania Age: 40 Posts: 99 Member: 1119968 Status: Offline Thanks Meter: 10	the problem is that at 350 celsius i can heat the board for 3-5 minutes an i'm unable to lift the ic. Is my station defective ? the air temperature seems to be correct , measured with a multimeter thermocuple at the nozzle output.. yesterday i tried to replace a keyboard filter on an e51 , and heated the board at 370 celsius for over a minute and still been unable to lift the ic , after over 3 minutes i lifted the ic but it came with 3 pads from board .. ONE minute at 370 celsius seems death for almost all IC's .. where is the problem ? is my station deffective? the air flow is little under middle.

02-26-2011, 21:18	#6 (permalink)
Kytan666 Freak Poster Join Date: Sep 2009 Location: Iasi , Romania Age: 40 Posts: 99 Member: 1119968 Status: Offline Thanks Meter: 10	ok ill make a preheater, but i see a lot other people(mostly youtube videos) working with only hot air and working very fast .. where-s the problem ? today i almost cook't a K810 board trying to replace the joystick, and when i got bored heating with 370 celsius and only melting the plastic stick i boosted to 400 and removed but with a pad , 400 celsius and still not all the solder was melted ? ??????? . i use good flux, i have tryied without flux.. same results .. i noticed a difference on boards, for example old siemens / philips boards work great at 350 celsius , but on nokia boards only chance to remove something with hot air is at 390 celsius witch is extreme.....

02-26-2011, 21:59	#7 (permalink)
..::SuB::.. No Life Poster Join Date: Aug 2008 Location: The Matrix :) Age: 36 Posts: 654 Member: 833760 Status: Offline Sonork: 100.1597150 Thanks Meter: 114	use good solder flux. with this you will work faster and safer. Apply some flux to the joystick's soldered pins and than heat at max. 350 celsius. maybe you have to use more air, but not much because it can damage the pcb too. EDIT: and also you need to waith 2-3 minutes after turn on the hot air gun because it need time to reach the configured temperature. Expensive solder stations work much faster, but these cost are about 400$.

02-26-2011, 22:00	#8 (permalink)
gbluez No Life Poster Join Date: Jul 2004 Posts: 11,049 Member: 73565 Status: Offline Thanks Meter: 5,062	put some leaded tin with soldering iron around the solder pad before you going to lift up some part. it will soften it. lower temperature of hot air will do the job smoothly. if you do rework with lead free materials, component soldering temperature specifications must be strictly obeyed. it's a high risk, 400' C long time exposure is crazy. just make it leaded, forget about those ROHS things.