Hyundai HLT-2001B schematics

[Learn2Day]

Re: Hyundai HLT-2001B schematics

Oh man, this is getting tough, only component in inverter circuit that affects all 6 outputs is U303, I've measured it inside out and I could swear it's working properly, only thing missing is proper outputs and brightness adjustment input. Unfortunately i do not have one available to test and there are none in my retailers stock.

I'm out of ideas.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

BL_ADJ/BRT_ADJ reads 0V. This what I've been saying. It's 0V from Q502 forward (page 3).

[budm]

Re: Hyundai HLT-2001B schematics

If you disconnect that line form the pin, then use external DC voltage such 1.5V batteries as the source, then you can see what happen.
If Q502 is stuck on or has C to E shorted, then that will cause 0V. If you short B to E which will turn off Q502, then the Collector voltage should rise up.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

That's not an easy task. The same connector feeds logic board and returns Vdd and ON/OFF. Best way of doing that is cutting the wires and that's something I'd like to avoid for now.

I guess I'll start with Q502 instead. I'll post back results.

Thanks.

[budm]

Re: Hyundai HLT-2001B schematics

Just short out E to B that will bring the Collector voltage up if the transistor is good.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

C to E not shorted, shorting B to E didn't rise C. I've found a jumper in BL_ADJ! Will remove it next and post back.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

Just short out E to B that will bring the Collector voltage up if the transistor is good.

Shorting B to E didn't rise C voltage. Does this means the transistor is busted?

[budm]

Re: Hyundai HLT-2001B schematics

That sure looks like it, when you short E to B, the transistor will no longer get the Bias current to turn it on, that is why the Collector voltage will rise up. You can lift the Collector pin also to verify that nothing else load down the voltage, you can see Collector resistor which is connected to the voltage source.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

Hi guys, sorry for the long absence but my mom was sick and I needed to go to her place for a couple of weeks...

Anyway, I removed Q502 and tested, it seems to be working fine, but even without Q502, i still have no backlights!!
I tested BL_ADJ without Q502, reads 5V and no BL, after this i removed a shunt to interrupt the 5V feeding and still nothing.. I'm septic to believe the issue is in Q502, but I also dunno what else to do.

Any Ideas?

Thanks!

[Learn2Day]

Re: Hyundai HLT-2001B schematics

please help..

[budm]

Re: Hyundai HLT-2001B schematics

Sorry, I ran out of suggestion at this point.

[Learn2Day]

Re: Hyundai HLT-2001B schematics

Yeah, I pretty much expected that, I guess i was just looking for validation before I bin it.
Snif...

Cheers!