Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
I believe it's for the 12V cooling fan.
I believe it's for the 12V cooling fan.
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Hi Redwire, thanks for the reply. Good thought but the fan has 2 wires and is plugged in at the other end between the fan and heat sink. You can't see it in the pictures.
The connector in question is at the two 8 pin IC's . I think one is an op-amp and the other a pic maybe. I was thinking maybe there were indicator led's or a mode switch, just guessing.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Well turns out the WF-88XX series is older and discontinued. The 3 pin connector is for a switch to toggle through the different modes. After days of internet searches that's all I found. I guess if the fan came on sooner it would help.
Enough time spent on this, it works now so good enough.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
WFCO's website and photos are shit, I found one pic implying the connector goes to the fan and another showing a front panel 2-pin connector. But the WF-8855E doesn't have anything for controls. I thought the PC board connector might be used for factory calibration where they solder in that selected resistor R50 next to it. Or for programming the MCU.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
You could be right Redwire,the connector has one pin to ground, one pin to pin 3 of the pic and one pin to a 330 ohm resistor then to pin 6 of the pic120508A. R50 may be for setting current limit ?, the same board is used for 3 different current outputs. Learned a bit from this board, probably use it to power other projects at the bench for now.Last edited by kiloamp; 12-09-2022, 05:39 PM.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Kiloamp I'm working on the same supply. Is there any way you could take a pic or tell me what the little transistor U6 is. It's the one that's close to the Large Red 12 V output lead is. I'm not able to identify mine. I tried to zoom in on the picture but it gets blurry just about the time I am able to read it. ThanksComment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Hello Shadetreetrader11, U6 is a KA431az. It's a programmable shunt regulator,
https://www.onsemi.com/pdf/datasheet/ka431-d.pdf
Do you know what CN2 connects to ?Last edited by kiloamp; 12-27-2022, 07:58 AM.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Thank you kiloamp. I don't know exactly what cn2 is. If I had to guess it would be for the use in diagnosing the working of the pic12c508a micro controller. Depending how it's programmed you can hook a special connector on to it and manipulate it to run threw a few of its various tasks. I was reading on wfco's web site trying to figure this out a little bit and they talked about how the power supply will charge at a certain current for a certain about of time and then back off on the current so the battery isn't being over charged. WFCO gives out 0 information on board level repair. Hope this helps.Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
Your welcome shadetreetrader11. So I'm guessing that CN2 is not connected to anything in the motor home, is just for programing and test ?Comment
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Re: WFCO Camper Converter need help understanding KA3846 SMPS Controller
That's correct. The connector that the fan for this power supply uses looks almost identical to this connector only difference being it has only two pins on it.Comment
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I have this WFCO Camper converter. You plug it into 120v and it puts out 12v 55 amp. After replacing all the bad parts the unit does not work, output voltage is 0.00 volts. There is 2 white ceramic resistors that put out a lot of heat and they burn up all the parts around them. So the main parts to burn up are the capacitors. When I just change out the caps to unit works but the KA3846
SMPS Controller sometimes goes bad and that has to be changed. When I change out the KA3846 the unit does not work anymore.
I read on the datasheet that the KA3846 can go into shutdown state.... -
hi,im trying to fix my converter unit that has no 12vdc or 120vac
when i plug 120vac on it directly,there is no 12vdc coming out and vise vesa....
now i check most all fuses,resistors,capacitors,ect... the thing i notice i have no voltage on my 2 big capacitors on the 120vac....there is no diagram for this board on net that i could find.all help or info would be appreciated.... -
This relic from a technology path that came to a dead end (but still has historical interest) was brought in with a dead SMPS, which is based around a MK1210 device. I got it going after a battle. It seems to have a strange design - if it's not getting feedback that the secondary is OK it cause the big FET to go into full conduction and overloads resulting in a blown fuse at best or something worse! I'm using a Dim Bulb Tester (70W/230V) which thankfully has saved the day a number of times whilst repairing.
Now, it loads a CD OK. The motor voltage output (which is built onto the SMPS... -
The NB670 NB670GQ is a fully integrated high frequency synchronous rectified step-down switch mode converter with 3.3V fixed output voltage. It offers very compact solution to achieve 6A continuous output current and 9A peak output current over a wide input supply range with excellent load and line regulation. The NB670 operates at high efficiency over a wide output current load range. Constant-On-Time (COT) control mode provides fast transient response and eases loop stabilization.
Under voltage lockout is internally set as 4.65V. An open drain power good signal indicates the output...10-23-2024, 03:23 AM -
I'm trying to fix this Canopus converter so that I can convert lots of old VHS cassettes. The problem is that it turns on for a split (and I mean split!) second, the fan jerks and then.. nothing. I've checked the power brick works. I've opened up the converter itself and been testing for shorts.
The image attached shows the on/off switch (which I've checked works) to the left of the yellow socket. Below the yellow socket is a green block marked 26 with a strange symbol at the front. Putting my probes either end of this block, on the silver parts, gives an open short...
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