Westward model: 1JYU9B schematic help

[Elric]

I was wondering if someone can please help me find the schematics for this car battery charger. Ive looked over the internet extensively and Im starting to think the schematics aren't available. The SMPS board number is E105119. Theres also another identification number below this one: HCE05RMX.

The problem Im having is that the relay that sends the mains voltage to the transformer is not receiving enough voltage to switch on. Any help is much appreciated, so thanks in advance.

[R_J]

Re: Westward model: 1JYU9B schematic help

Post clear, high quality, straight on pictures of the yop of the board and the bottom, they must be clear enough to see where the traces go, also include any IC numbers if they are not clear or readable in the pictures.

It could be a weak startup cap causing the problem.

[Elric]

Re: Westward model: 1JYU9B schematic help

Sorry for the late reply. I work nights and weekends, with a bit of an odd schedule.

The IC’s are as follows:
EM78F734NSO20J 20-pin microcontroller
VIPER22A 8-pin MOSFET/PWM
EL817 the two 4-pin optocouplers

[stj]

Re: Westward model: 1JYU9B schematic help

there really isnt much to go wrong, maybe it's a weak opto-isolator

[Elric]

Re: Westward model: 1JYU9B schematic help

Well thats what I thought too until I started measuring the voltage on the main transformer of the charger and was getting nothing. After that I checked the relay on this board and its only getting 5~6V ; probably half of what it needs to activate and send the mains power to the main transformer.

[stj]

Re: Westward model: 1JYU9B schematic help

how does it work?
does it power up if the battery is low or just run all the time?
i dont see why it needs a relay if it's just a trickle-charger.
if the psu is dead, replace the small electrolytic that starts the Viper chip
c04, and c05 just to be sure, not sure what c05 is doing.

[R_J]

Re: Westward model: 1JYU9B schematic help

You likely need to have a battery connected before the charger will work, Also the battery can not be dead, I would connect a known good battery and see if it starts to charge.
Check the voltage across C04, it should be around 15vdc, if it is only around 8vdc the ic is shutting down.

[Elric]

Re: Westward model: 1JYU9B schematic help

@stj the charger runs all the time. It has the 100 A engine start feature. It used to spark/ark if you touched the battery clamps together. They were gonna throw it away at work so I took it home. Theres another one thats not working too; both of them are pretty new, they just probably got treated rough by dayshift

@R_J Do you mean check the voltage across C04 while the charger is under load ( connected to a battery ) ? Also I was wondering if L01 ( between C01 and C02 and the Viper ) is a coil that is part of a buck converter, like in a Buck converter on a computer that lowers a main power rail to a 5 or 3 volt power rail? Because it almost seems backwards to me. Theres 169 V coming of that rectifier. It would seem to me that it would need the power to go through a couple mosfets and then the coil. I feel like Im missing something here. Ill check what I got across C04 in a couple hours. At work atm.

[stj]

Re: Westward model: 1JYU9B schematic help

the viper is a combined driver AND mosfet.
if jokers have been shorting the output to get sparks then maybe a complete recap would be wise

[Elric]

Re: Westward model: 1JYU9B schematic help

Ahhh you may be right. Ill be pulling a few caps off and measuring them in a few minutes then. Would you happen to have any insight on exactly what the role L01 plays? It seems like an awful small coil to have much of an effect.

[R_J]

Re: Westward model: 1JYU9B schematic help

Check the voltage across C04, it should be around 15vdc, if it is only around 8vdc the ic is shutting down, You don't need anything connected to do this voltage check, It will tell you the state of the VIPER22A, L01 is just for noise suppression, high frequency blocking, it is just a ferrite bead over a piece of wire.
C04 needs to charge up to 15v to keep the ic operating, the viper22 pulses the transformer primary creating a voltage on the small secondary winding connected to D02, charging C04

[Elric]

Re: Westward model: 1JYU9B schematic help

Just an update:

So while checking voltages on this board I managed to short something out. I ended up blowing the fuse and the rectifier. I'm going to buy all the caps and a rectifier for this board, and possibly more on the chance that the other charger has the same issue. I'll update this thread when the parts get here. I'm not sure what I shorted as it happened when I took my eyes off the board to look at the meter and my freakin probe slipped.

Fun times.....

[Elric]

Re: Westward model: 1JYU9B schematic help

Does anyone happen to know of an interchangeable Vipper22A F54902?

Im finding plenty of viper chips online, but none of them have that F54902 designation.

[Elric]

Re: Westward model: 1JYU9B schematic help

Heres a pic of the chip

[stj]

Re: Westward model: 1JYU9B schematic help

those numbers are just date & batch crap
just make sure you get the DIP version and not the surface-mount one.