looking for a schematic /advice on CT-852K hot air station

[pecrie]

I am using this reworking station for some time but not too extensive.It is doing ok , but sometimes it takes very long to get a part of the board.

Now I did a temp measuring and on the highest setting = 480 C my temp meter with the K-type element shows 398 C as highest.
Yes , it is not that accurate.

Is there a way to up the maximum temp a bit more , or is the 398 C a way , to let the heat element have a longer life ??

Any thoughts are welcome

[stj]

Re: looking for a schematic /advice on CT-852K hot air station

temperature drops fast over distance, where was the k-probe?

[pecrie]

Re: looking for a schematic /advice on CT-852K hot air station

I was using the 3mm nozzle and the K-type sensor was 3mm away from the outlet.

This is according to instructions of the manual.

[stj]

Re: looking for a schematic /advice on CT-852K hot air station

well i can say this, if you want over 400' you need to use a big nozzle and turn up the airflow or the plastic handle can start to melt! the heat gets trapped if the nozzle is too small

[pecrie]

Re: looking for a schematic /advice on CT-852K hot air station

Yes , when the heat gets trapped inside the nozzle house it's Obvious that the air which comes out must have a high(er) temperature.

The air will get warmed up from the air that comes from the heater - there is more air coming in than what (can ) go out.Also the air inside the nozzle will take up heat from the nozzle itself.

So measuring the air temp this way should give an indication about the air temp - at different air speeds and temp settings
.When you are going to work on a smd part , that will be a different thing in my opinion.

[stj]

Re: looking for a schematic /advice on CT-852K hot air station

i have had these things glowing red in the past using small nozzles!!

[pecrie]

Re: looking for a schematic /advice on CT-852K hot air station

Well it seems that I didn't put the K - element in the middle of the air stream.
I fixed both the gun and element and the temp is now going over 400 C with the max temp of around 445 C .

While the max setting on the station is 480 C .But this 450 is not helping to get a QFN 6x6 mm of the board in a reasonable time ( 30 ~ 55 seconds ).

So I have bought a Quick DSW 861 because of the overall good revieuws and the easy controls.

So I'm good to go for now ... ))))

[stj]

Re: looking for a schematic /advice on CT-852K hot air station

you need to heat the underside of the board first, your going to do track damage otherwise.
and flood it with flux, it will spread the heat under the package.

what are you fixing?

[ecking767]

Re: looking for a schematic /advice on CT-852K hot air station

buy a pre-heater plate to heat up the circuit board

[pecrie]

Re: looking for a schematic /advice on CT-852K hot air station

Yes guys , I know that for a big QFN or GPU / Southbridge chip you need to have a pre - heater to warm up the underside of the MB.

But here I am talking about a QFN with the size of a double mosfet (6x6 mm - not centimetres)

I know that they have groundplane and are soldered with leadfree solder.Which is making it harder to get them off.And I don't want to heat up the board too long at 450 C.

This CT-852K has an air volume of 23L/min - the Quick has 120L /min.

Also some months ago I did buy a BGA reflow station (an IR 6000 clone).I did not use it yet.
But I did make a profile to check if it is working ok.So it seems to be good.

I do have some MBs where I must replace the GPU or SBridge.But I understood that you need to bake the new ones first , for 1 or 2 hours.

I have a small stand alone pre-heater that I will use for this purpose and put a metal box on top with the chip inside.And checking the temp with a K - type temp meter at around 100 Degrees C .

I have seen L Rossman and others taking the small mosfets from the board in 11 ~ 30 seconds.So with the Quick I can do this also.

I'm repairing a HP G7 MB at the moment - see my other post

[xmetal]

Re: looking for a schematic /advice on CT-852K hot air station

I used to use a Zd-939a hot air station and it was hopeless at getting to a temperature or maintaining it so I recently upgraded to the Quick 861DW. It has made a world of difference to hot air rework.

I do have a Honton r392 BGA rework station for the bigger chips but I tend to use it mainly for pre-heating boards.

[ecking767]

Re: looking for a schematic /advice on CT-852K hot air station

then you will need KESTER 186 RMA NO CLEAN LIQUID ROSIN FLUX FOR SOLDERING and Desoldering. unleaded solder melt around 450 F to 470 F. Make sure the flux is under the chip and use a good amount of flux.

[pecrie]

Re: looking for a schematic /advice on CT-852K hot air station

@xmetal ,

I looked up the Honton and it seems to be a bit more professional than an IR6000.But for what I'm doing the 6000 is good enough.
Yes I do agree that the Quick 861 is a world of difference compared to my old hot air station.

Now I have the mosfets and small components off in seconds rather than in minutes.And I can reduce the air flow so parts will not fly off the board.

I bought a small pre-heater from Gordak the 853 model for when I may do some reballing.