sorry 4 being greedy but... another patient samsung245B plus

[masterbateson]

Sorry to drop a few on you guys at once but here is another I thought potential easy fix I got from Eblag.
I thought i might be able to get myself a bigger monitor on the cheap.
So far no luck.

This Monkey is another samsung(do you see a pattern emerging or is it just me??)
its a Model?245Bplus or model code LS24hubcbl/edc or type HU24BS

Set appears to be dead/ no back light etc
PSu fuses ok not blown, no bulging caps visible, not tappable, a solder up did nothing.

Any tips/ideas would be great. PSU is a dong yang BN44-00195A

I have cleaned up the board and scraped off the Brown old glue stuff as suggested in another thread somewhere.
But the Patient is still flat lining /dead/in a coma.
Any help would be greatfully received.
Wondering whether to just blanket swap a load of caps or wondering if its summat else?
Ta
Paul B

[cpt.charlie]

Re: sorry 4 being greedy but... another patient samsung245B plus

Post a good quallity photo of the board and start measuring the output voltages.

[1supertech]

Re: sorry 4 being greedy but... another patient samsung245B plus

Their are 3 68 ohm resistors close together near a serial number on power supply test and replace.

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

Thanks Supertech thats a great place for me to start!

All you guys are a lot more current in testing fault finding and working on stuff.
I am more than a little bit rusty, last field service job i just left after 10 years i dont think i broke a meter out more than twice and def could count on one hand

It seems that the power supplies these days are somewhat different from the old CRT days.

Do sets not trip any more/tripping, with the old TV's if a switch mode PSU had failed you could here it clicking, doesnt seem to happen any more?

Also in old days you used to be able to disconnect the Psu from line output stage and wang a 60w bulb for instance on the 100 odd volt line to load the Psu while testing.
Seems like you dont do that any more.

P.s. with these modern tellys/monitors, if the set is giving symptoms like its dead, but you do have something as in a flashing standby LED is it safe to assume the PSU is shutting down for some reason? and If so Am i likely to get/have any outputs?
Ta for replies guys, i will get picks up today, and break meter out and check those resistors.
Would be great if its them.

[re-atari]

Re: sorry 4 being greedy but... another patient samsung245B plus

Their are 3 68 ohm resistors close together near a serial number on power supply test and replace.

Sadly not on this one. The 3 failing 68R resistors are only present on the 137A PSU used in 245B's.
The OP has a 245B Plus monitor with the much dreaded 195A PSU. He might consider buying a used 137A PSU, as they are much easier to fix when failing. On these usually only one of the 3 68R resistors fails (goes open circuit).
I have successfully fixed several 137A PSU's in the past years, whereas my success rate with fixing 195A's is exactly zero.

re-atari

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

You said no backlights, but do you at least have the standby 5V Voltage?

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

Mr Atari is exactly right, there is deffo no three resistors on this one. here is a piccy or 2.





I will pop board back in the set and get the meter out and test some voltages.
Anyone got a circuit diagram for this set?

I suppose i could always get one of these other PSU boards if i can find one, and if they are interchangeable.

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

What are the numbers on the barcode sticker?
That is not BN44-00195A.
BTW, what is that bare wire soldered on the bottom side of the board? It looks like the bottom side soldering works need to be cleaned up and inspected.

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

The wire is just a cap i replaced, as mentioned earlier in post, the print lifted a little so just to be on the safe side i soldered the cap leg to the next cap along on the same rail/track.
Yup its not had a clean yet, and will be made to look more pretty/proper job before i put the board back,
That is if its going back in,

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

Serial number sticker as far as I can tell(could hardly read as so small) was/is
cn07bn440050ask28d7e2621 the a in ask could be a four as print is smudged.

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

What a jack ass! I posted wrong pics in the wrong posts and i cant seem to edit my above post with the pics.
The PSU out of this monitor is in fact this one.
http://i1081.photobucket.com/albums/...psqwydeovv.jpg

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

So are you at least getting any standby Voltage?

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

I will have to lob it back in the set to check, or can you test this out of the set?

Struggling with time at the mo, but hopefully get a chance tonight.

A quick dummy question, but are standby voltages usually 5v or 12v these days?

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

You can run the board by itself to check the standby Voltage without having another boards connected to it, just have to be real careful not to touch anything in the primary side with your body/hands.

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

well just having a quick poke around and seems like ive got nothing on anything on the secondary side just ikkle Mv's. def no 5v or 12v on anything.

240 going in, both fuses intact, bridge reccy is fine, thats as far as Im up2 so far.

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

well just having a quick poke around and seems like ive got nothing on anything on the secondary side just ikkle Mv's. def no 5v or 12v on anything.

240 going in, both fuses intact, bridge reccy is fine, thats as far as Im up2 so far.

Then we need to find out if we have about 330VDC between the two legs of the main filter cap or not.

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

we do indeed bud

[masterbateson]

Re: sorry 4 being greedy but... another patient samsung245B plus

if i have the psu switched on live and connected to the main board, and then measure the standby voltage its jumping around mostly around 3- 3.5 v (all over the place really looks for a fraction of a sec its at 5v but its def not stable.

[cpt.charlie]

Re: sorry 4 being greedy but... another patient samsung245B plus

Maybe your main board is taking too much power due a shorted component, check for any overheating component, specially linear regulators, however i would check the PSU without anything connected to it, 5Vsb should be stable in that case.

If you have a lab PSU try to feed 5V on the main board to determine if the board is taking excesive current.

[budm]

Re: sorry 4 being greedy but... another patient samsung245B plus

if i have the psu switched on live and connected to the main board, and then measure the standby voltage its jumping around mostly around 3- 3.5 v (all over the place really looks for a fraction of a sec its at 5v but its def not stable.

At least we know that you do have DC on the main filter cap otherwise you will not see any DC at the output connector at all. I thought you said you do not have any DC on post #15.
It is confusing when the information is not clear.
Is the 5V steady if you do not have the main board connected it?