N313 09 Transistor

[Steve T]

Hello

Iam working on a Hakko 850 hot air station and need help finding a transistor.  It is marked “N313” with “09” below it. It is a through hole component with 3 legs and has a half cylinder shape (I’m new to electronics repair).  I have searched online but I cannot find a definite part or substitute.  Some sites call it a NPN transistor others call it a mosfet or a triac. Thanks in advance for any help.

Steve

[floobydust]

I did find this schematic for Hakko 850B and see a unijunction transistor PUT1 as "N13T1" (NEC) in the TO-92 package pic or 2N6027 as a substitute. That might be what you are looking at. It would also test weird even though good.
other pics https://www.eevblog.com/forum/reviews/hakko-850-hot-air-rework-station/
Usually the triac gets cooked in these, heater shorts out etc.

[Steve T]

Thank you for the reply.

I have seen the 850B schematic but it looks different from the 850 that I have.

I have attached a picture of the board and the component being tested on my Peak DCA75. 

The transistor fits in the spot marked D11, between the blue and green capacitors.

Could the transistor be a small signal thyristor (I’m not sure what that is)?? Or maybe the transistor is good but cannot be tested on the analyzer?

Steve

[floobydust]

Not an 850B or 850B-3 but the early version. It's a bit of a mystery. Can you give a pic of the other side of the board, to figure what the part does. I can find no data on N313. Japanese discrete or thyristor databooks i.e. NEC never made it to the Internet.

The PCB is labelled as if it's a small triac - A1, G, A2. Typical parts are MAC97 or BT131 series or Z0106, all in TO-92 package.
Small chance it could be a DIAC, if only 2 terminals are used. That makes more sense for pump speed control and would likely test open circuit as they don't do anything below ~30V. But you never know, Hakko was a bit unusual with their electronics designs of that era. So I thought to trace out the circuit a bit. Conn. VH3 is to the air potentiometer?

I'm guessing bigger triac TH2 is for the pump, and H1 on the heatsink is for the heater.

[Steve T]

I have attached a photo of the back of the board and drew a boarder around N313.  You are correct that the middle pin is not used.  If I test the two outer pin on the tester, the screen indicates that it is a diode?

Also, I found some broken traces where a plug inserts and have soldered some wire leads to repair the.  The heat now works. 

When I plug the unit in, the air pump works for a minute, then shuts off, which is normal.  When I turn the unit on, I get heat and airflow, but cannot adjust the speed and the LED indicator does not light up.  If I power off the unit, the air continues for a minute then shuts off, which is normal.

Steve

[Steve T]

I believe that I solved the problem.  There was a broken trace where the diode connects to the wires post for the LED at the pump speed control.

[Steve T]

Nope…..still having trouble with air speed.  Seems to be stuck on maximum.

[fzabkar]

TVSN13T1 and N13T1 are both substituted by NTE6402:

https://www.nteinc.com/specs/6400to6499/pdf/nte6402.pdf

[Steve T]

Thanks fzabkar.  Could the N313 be the.reason 5hat I can’t control the speed of the airflow?

Stev

[floobydust]

OP what you describe does not make sense to me. D11 is now in-circuit? Connector VH3 to the air pump?
The mystery part D11 connects to the triac TH2 gate, so I expect nothing happening, no power to VH3-3 if the part is out of circuit.

The PC board has a lot of lifted pads and traces so I would suggest improving the desoldering skills. It is a cheaper phenolic board.

[Steve T]

Hi floobydust

Yes it is back in circuit and the air pump is working but only at full speed.  The pads were lifted when I got the unit.  Actually, one of the capacitor legs was popped off of the board and the unit’s cool down function wasn’t working at all.  At least I fixed that.  Also, I didn’t realize that phenolic boards were more subject to damage.

It’s true that am new to this hobby (my background is in healthcare) and am trying to learn as I go.  Sometimes I buy old electronics that no longer work just to learn from them.  Many times they end up worse than when I started, LOL.  I’ll keep at it though and hopefully improve.

Thanks for everyone’s help.

Steve

[floobydust]

If the air pump is stuck at full speed, check triac TH2 for being shorted: T1-T2 open, T2-G open, T1-G 150-250Ω
NEC AC05D 400V 5A TO-202 package, I'd go for a BT137-600E.

Check the resistance of the Heater potentiometer (yellow wires VH3) to see if it is OK. Air "1" is 300kΩ, "8" is 0Ω.

Found this, never used nitrogen before: Hakko 850 Modification for Nitrogen Supply

[Steve T]

Got it!  The VH3 resistance at position 1 was too low.  I rotated several times while pulling on the control knob.  It now reads 287 k ohms.

Thanks for your help!

Steve