Tip122 Replacement

[TorqueRanger]

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....
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..
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 ???Could I use MOSFET instead of the Darlington ??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
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??  Or is the 2 Darlington sharing the heat so one doesn't over heat

[Paul Price]

If it ain't broke don't fix it.

I would trust the engineering skill that went into the design to be reliable and your guess of how hot is too hot not.

[ivan747]

 Aoyue isn't such a great brand with good engineering, I think you should definitely check that.

[TorqueRanger]

Aoyue isn't such a great brand with good engineering, I think you should definitely check that.

If it ain't broke don't fix it.

I would trust the engineering skill that went into the design to be reliable and your guess of how hot is too hot not.

I know it's not the best but I got it used for $25 shipped .. I figured it would need to mod some stuff or replace the cheap Chinese copy components with the real deal and much better soldering job..
But right now it needs some repair work which I plan on fixing but the heat of the 2 Darlington bothers me.. So I was going to add heatsinks and possible change up the 2 5 amp Darlington to 1 10amp Darlington .. I was thinking the 2 darlington was sharing the heat load instead of one large heat load .. What do you guys think???

[ivan747]

I haven't seen the insides of this, but, can you fit a small heat sink or a tiny fan?