Tip122 Replacement

Discussion in 'General Electronics Chat' started by Dr.killjoy, Oct 28, 2014.

  1. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    I just got my used Aoyue 6028 today... So I decided to take it apart and check it out and the safeness of it since it was made in china .. To my surprise its not to bad I think .But it has 2 TIP122 stack on each in one hole but sure the purpose but still checking it out....
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,447
    3,363
    Maybe they needed the extra current. TIP122 is rated at 100V, 5A.

    TIP142 is rated at 100V, 10A.
     
    Dr.killjoy likes this.
  3. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    Not sure but it hooks up to the blower fan which is a 12v 1w fan.. I was thinking that they are prone to failure and that's there as a back up... I was looking around at the Tip102 but the Tip142 might be a better option ...

    Sorry correction
    The tip122 power the fan but goes to the control board and might power the heating element but not sure.. I will have to do some leg work and find out how it works..
     
    Last edited: Oct 28, 2014
  4. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,771
    971
    Solder job looks "bulbously".. cold :)
     
  5. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    I know my plan so far was to replace every component with a name brand new one and use my Kester 44 solder for nice joints.. Oh I only paid $25.00 for the hot air station shipped to my house..
     
  6. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    And IIRC; a darlington.
     
  7. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    Well I did some more work and frankly it scary as hell working on this thing... The blower motor is is not terminated right and wire are exposed ... The 2 Tip122 get really hot and have not heatsink or even a fan blowing on it .. I would like to redo the PCB with a better design and more room for a heat sink but cad skills suck and I have a hard time even trying to use it ..So does anyone have any ideas ???



    What does that mean??
     
  8. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,792
    948
    no no. chinese good.
    look good, work fine.
    last long time. :)
     
    Dr.killjoy likes this.
  9. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    A darlington is 2 transistors connected together in the same package - the gains of the 2 transistors multiply.
     
  10. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    Could I use MOSFET instead of the Darlington ??
    I know there is 2 transistors inside but not sure what that means or the gain means..
     
  11. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    In a darlington; the 2 base/emitter junctions are in series, so you have to top 1.4V to get current flow - but you only need much smaller current than with a straight transistor.

    A power MOSFET is a voltage operated device, there's only current in the gate if you have AC charging and discharging the gate capacitance.

    A typical power MOSFET needs about 8V on the gate to pass the headline drain current, small signal types can respond to as low as 1V.

    You can get logic-level MOSFETs with guaranteed VGSthr specifications.
     
  12. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    The Darlington is feed from the transfomer with ac voltage which head to a triac that controls the heating elements ..What I am trying to do eliminate the double stack Darlington's and possibly use only one but not sure of the 10 amp rating will be enough or use a logic lvl get.. Do you think I should reuse the board or try building a better one ???
     
  13. ian field

    Distinguished Member

    Oct 27, 2012
    4,415
    784
    The TIP11x darlingtons are only one transistor package - of course there's nothing to stop you assembling the darlington yourself from 2 discrete transistors.
     
  14. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    If you loom at both pics the company stack to 5 amp darlington together .. I would love to build a circuit to replace the darlington but to be honest I wouldn't know where to begin cause I am still a newbie and still learning..
     
  15. Dr.killjoy

    Thread Starter Well-Known Member

    Apr 28, 2013
    1,190
    156
    I was thinking last night and I wondered if I could remove the 2 tip122 and mount remotely 1 Tip142 with a large heatsink on perfboard with using wires to connect the two??
     
Loading...