Need help to id part

[1-3-2-4]

A few things on this board as I'm trying to find if anything is shorted.. they seem to be all SOT parts.

in the first pictures the parts that say M3A and M4A

The 2nd picture:

241 & 1114/50B202
And the last one what is SG03?

 

[WTP Pepper]

try googling the markings + sot23. It works wonders.

 

[1-3-2-4]

Well you see here is something.. a SOT with the markings 241.. my catalog says that's a Zener diode SOT346 but when I look up the part number from the catalog it's saying it's a voltage regulator, and only has connections of 2 of the 3 pins but when I check mine I have continuity on all pins and it acts like a diode by only allowing the current to pass one way.

 

[1-3-2-4]

How about this capacitor

**broken link removed**

 

[tvtech]

Those fat blue Caps never fail. The one squatting I mean.

I believe it is a Y Capacitor. See here..not really accurate but a guideline nevertheless: https://en.wikipedia.org/wiki/Filter_capacitor

The ones that do fail are the the thin blue ones working on the PSU Primary. Not X or Y Caps....just llittle "ceramics or anything really small rated at 2KV and normally Blue"

They tend to get cross and either Trip or blow SMPS. Depending on the SMPS design....

You are hunting in the wrong area 1-3-2-4

Regards,
tvtech

 

[1-3-2-4]

I've been hunting now for 3 months now.

 

[tvtech]

I've been hunting now for 3 months now.

Then I need to sit you down and help you step for step here on ETO over the Internet. Hopefully Nigel will chime in too...

3 Months is a long time you have been battling.

Be patient, Nigel will see this and hopefully help too. Long day at work here. Not much energy for this.

Regards,
tvtech

 

[1-3-2-4]

Then I need to sit you down and help you step for step here on ETO over the Internet. Hopefully Nigel will chime in too...

3 Months is a long time you have been battling.

Be patient, Nigel will see this and hopefully help too. Long day at work here. Not much energy for this.

Regards,
tvtech

yeah I don't blame you haha and I got this projector for a great deal because of the no power issue, I thought it would be simple but I can see that's not the case here

I'm going to have to order another MR4010 anyways since it has so many legs on it that it's impossible to save when pulling it out. it should arrive sometime next week hopefully.

 

[misterT]

Those sot-23 devices are transistors:
M4A = MMBT4401 (https://www.electro-tech-online.com/custompdfs/2013/08/2N4401.pdf)
M3A = MMBT4403 (https://www.electro-tech-online.com/custompdfs/2013/08/2N4403.pdf)

source: **broken link removed**

 

[1-3-2-4]

Those sot-23 devices are transistors:
M4A = MMBT4401 (https://www.electro-tech-online.com/custompdfs/2013/08/2N4401-1.pdf)
M3A = MMBT4403 (https://www.electro-tech-online.com/custompdfs/2013/08/2N4403-1.pdf)

source: **broken link removed**

Thank you! is it possible to test them? Assuming it need to come out of the circuit.

 

[throbscottle]

SG03 is a spark gap. Very unlikely to be faulty.

You can do a rough test of the transistors with a multimeter. They should look like two diodes back to back - npn looks like common anodes, pnp looks like common cathodes, where base is the common point. Should look like open circuit between collector & emitter. Beware of false readings when testing in-circuit due to other components.

 

[1-3-2-4]

SG03 is a spark gap. Very unlikely to be faulty.

Hmm never heard or heard of this term before, what's it role in a power supply?

 

[throbscottle]

It's just two electrodes separated by a gap. When the voltage across it reaches a certain level, it arcs over, protecting the circuit it's connected to.

 

[1-3-2-4]

It's just two electrodes separated by a gap. When the voltage across it reaches a certain level, it arcs over, protecting the circuit it's connected to.

Oh ok got it

 

[Nigel Goodwin]

You can't repair things by randomly testing components, you first need a schematic, and then an understanding of how it works (in order to find why it doesn't).

 

[1-3-2-4]

You know they have no schematic of this board right? You know the company themselves don't have a schematic of the power supply.

 

[Nigel Goodwin]

That's why you get a pencil, and a piece of paper - and get busy.

 

[1-3-2-4]

That's why you get a pencil, and a piece of paper - and get busy.

Not sure why people assume this is going to be easy.. first of all I have no experience in drawing a schematic I tried yesterday but it ended up looking a mess so I just stopped, a lot of areas more so the output area has a copper layer between the board blocking any light on the underside of it, so it's anyone's guess of what connects to what in that area.

 

[throbscottle]

This is unfortunately common. The board is treated as an intractable whole, the attitude is that you buy a new product rather than repair the broken one, because it is cheap to make, expensive to pay someone to repair it, hence the schematic never sees the light of day outside the manufacturer.

Sometimes you can work out what is what, sometimes you can't. Sometimes you can take an educated guess as to the general area of the fault. It's made worse by multilayer boards where you can't see the traces.

Random component testing can work - I'm guilty of doing it, and found a faulty part, though not the real cause of the fault. I have a mains over ethernet box and a freeview box waiting for me to have the time for exactly this method.

1-3-2-4, if you are sure it is the smps which is at fault, many people say you should replace all the electrolytic capacitors even if they check ok with a meter because their esr goes up as they age.

 

[1-3-2-4]

These are brand new Panasonic caps, I spent $40 replacing them last month.. the brand that it comes with it are "elite" brand caps

i wish I could find a way around the PFC, can't I just get a isolation transformer and probe VCC & GND on the PFC to turn it on? I would of course use something under 12VDC

The whole reason is something is preventing the PFC from turning on because it's not getting voltage on Pin 8