Trying to identify the component in the pic. It's in an old car battery charger.
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Re: Help identify component
Looks like it is a UJT 2N2646 should work
I found the information here: https://forum.nutsvolts.com/viewtopi...0809b&start=15
Is it bad or does it just check strange?Last edited by R_J; 04-07-2019, 11:24 AM.
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Re: Help identify component
Hey, thanks for that. I turned the internet upside down looking for that and nothing fell out...lol. I dig around and see if I have one. Thanks again.
Haven't tested it yet. Didn't know what it was.Last edited by imaddicted2u; 04-07-2019, 11:29 AM.
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Re: Help identify component
Originally posted by R_J View PostLooks like it is a UJT 2N2646 should work
I found the information here: https://forum.nutsvolts.com/viewtopi...0809b&start=15
Is it bad or does it just check strange?
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Re: Help identify component
It won't check like a normal transistor. But if it checks shorted, it will be bad. http://www.circuitstoday.com/testing-a-ujtLast edited by R_J; 04-07-2019, 12:15 PM.
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Re: Help identify component
Here are some pics in case you are interested. It's a Motomaster model 11-1519 battery charger, 12 volt at 6 Amps. The circuit board has Tenatronics Ltd. 50-114 etched on it. They seem to be from Newmarket, Ontario.
The transformer that feeds the board is a 27 volt center tap.
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Re: Help identify component
It looks not bad, anything beats selenium rectifiers lol. Not hard to sketch a schematic. In the late 1970's lots of GE circuits for SCR chargers.
The blue Philips electrolytic caps, I find they don't last.
It probably eats SCR's if you short the output.
It looks more like a "programmable unijunction transistor" circuit?
Like this but drives two SCR's.Last edited by redwire; 04-07-2019, 02:14 PM.
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Re: Help identify component
Originally posted by redwire View PostIt looks not bad, anything beats selenium rectifiers lol. Not hard to sketch a schematic. In the late 1970's lots of GE circuits for SCR chargers.
The blue Philips electrolytic caps, I find they don't last.
It probably eats SCR's if you short the output.
The SCRs were soldered before I got it so they may have been replaced. I think whoever soldered it before used acid core solder.
The only protection is a little glass self resetting breaker in the output, I doubt it's much help for reverse polarity.
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Re: Help identify component
Motorola SU316 unijunction transistor. No NTE cross (like a SU112), not in my 1980 Motorola datasbooks. MPU131, 2N6027 are.
Also in this thread about Sears 10A battery charger: https://forum.nutsvolts.com/viewtopic.php?f=45&t=8342
But images gone due to third party aholes
The guy did not get the 2N6028 PUT to work, but 2N2646 UJT did ok.
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Re: Help identify component
I drew a schematic and it looks like a voltage-controlled oscillator that pulses the SCRs (trigger transformer). I'd guess it's a UJT or PUT.
I think the circuit has some issues... The snubbers are sort of terrible to have AC on electrolytic caps, and the zener should get supplied not from the trimpot. Unless I have drawn it wrong.
Why are the SCR's on an insulator but not the mounting screws? I think that would short the power transformer?Last edited by redwire; 04-07-2019, 11:14 PM.
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Re: Help identify component
Originally posted by redwire View PostI drew a schematic and it looks like a voltage-controlled oscillator that pulses the SCRs (trigger transformer). I'd guess it's a UJT or PUT.
I think the circuit has some issues... The snubbers are sort of terrible to have AC on electrolytic caps, and the zener should get supplied not from the trimpot. Unless I have drawn it wrong.
Why are the SCR's on an insulator but not the mounting screws? I think that would short the power transformer?
I didn't get notifications for these updates for some reason.
I drew this over coffee this morning.
This is a little more rudimentary than yours but here is my rendition...
edit...made corrections to original drawing
edit: adding pic of back of PCB lit up to see traces better.
The SCRs are isolated but from the back side.
Last edited by imaddicted2u; 04-08-2019, 07:22 AM.
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Orientation of 2N2646 Component.
Hi Guys
I am trying to fix one of these Canadian Tire Battery Chargers. Found your article and I'm taking a chance that my Battery Charger has the same issue as yours did. Ordered a replacement 2N2646 Transistor. Having issues figuring out the correct pin layout for the 2N2646 I seem to get conflicting Case/Pin layout for this component.
Questions
(1) Is the attached picture the correct pin layout?
(2) What is the correct Case for this part?
Thanks for your help
Willy
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