Hanns-G HG281D stuck on self test color mode?

[gordesky1]

So 2 years ago a surge hit this monitor:/ which years before i got it going again replacing the 2 16v caps on the main board C80 and C83.

After the surge all i had was a black screen with a blue led than it goes orange after secs.

So i took it apart to check it which i didint find no issues.. But my dam luck a screw driver drop on the psu and big spark happen and it blew the small 250v box fuse.


So it sat for a year till i ordered new fuses on amazon 2 days ago and got them in yesterday.

So i took it apart replaced the fuse and it has power again but just a blue light and you can see blinking on the black screen but no black light.

So what i did was get a hair dryer and heat up the main board were the caps i replaced years ago ago when i had fuzzyness and the controls was wonky and tried turning it on and bang the black light comes on and its stuck in a self color mode test going from rgb and greys and repeats ?

it detects the pc and the pc detects it cause it stays on but asoon as you disconnect it from the pc it will stay on for 5secs than go in standby.

What will cause this issue? i tried replacing the 2 caps with ones i had on a bad motherboard too see if it does anything but nope.. the caps are the C80 and C83 ones which i replace the ones i had on it which was 120uf 16v with 100uf 16v.


Now what i do noticed is the main board runs hot to the touch c80 and c83 is pretty hot and the middle chip burns you finger so im not sure if thats normal or what?

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Oh heres some pics. i forgot to mention when the screw driver drop a year ago the spark caught the LVDS cable and damage it a little... So hopefully thats not a issue either...

Tho i used a volt tester and tested each pad going back to the main board and they all checked out fine. And if i leave the cable disconnected all i get is a grey screen but when its plugged in it does the color self test so i assume its fine?


I would order the cap repair kit for it and recap the whole main board and maybe the psu too tho this does seem like a main board problem in my opinion cause it seems like everything is getting powered as it should tho not 100% sure .


Oh and also the monitor controls doeisnt work like the menu nor anything else while in the self test color mode nothing pops up.


Do noticed every cap on the main board is made by capxon... except the 2 c80-c83 ones i replaced back than and today.. I just not sure the chance if it can be them that causing this tho?

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

You have a lot of variables here (bad caps on mainboard replaced twice, power surge, PSU shorted with screw, LVDS connector slightly damaged...), so this one might be a bit tricky to get to the root cause (or there may be more than one.)

So 2 years ago a surge hit this monitor:/ which years before i got it going again replacing the 2 16v caps on the main board C80 and C83.

What cap brand and series did you use for those two caps and where did you buy the caps from?

If they weren't a known good Japanese brand and low-ESR long-life series, they could have just failed again.

*EDIT*
I see you used two United Chemicon KMG caps. While those are good Japanese GP (general purpose) caps, they are only rated for 2000 hours @ 105C. So in a hot environment next to those hot regulators, they may have already dried up.

So what i did was get a hair dryer and heat up the main board were the caps i replaced years ago ago when i had fuzzyness and the controls was wonky and tried turning it on and bang the black light comes on and its stuck in a self color mode test going from rgb and greys and repeats ?

it detects the pc and the pc detects it cause it stays on but asoon as you disconnect it from the pc it will stay on for 5secs than go in standby.

... and this further suggests bad cap issues, despite the fact that you tried replacing C80 and C83 again. Reason I say that is because those small caps you found on a motherboard are often GP caps with not great ESR. So there's no telling if they were actually OK or not.

Thus, at this point my suggestion would be to replace all of the caps on the main board as a first step. Make sure you do use good Japanese caps rated for 105C and long life, because as you can see from the darkening around the two regulators where C80 and C83 are located, that part of the PCB runs rather hot.

Any of the following brands and series should do the job here:
Panasonic FC, FR, FM, of FS series
Rubycon YXJ or YXM series
Nichicon PW, PM, PS, PV, PJ, HE, HV, HW series
United Chemicon LXV, LXZ, LXY, KY, KYB, or KZE series

Now what i do noticed is the main board runs hot to the touch c80 and c83 is pretty hot and the middle chip burns you finger so im not sure if thats normal or what?

It may or may not be normal.
Some monitors do have really poor thermals, and the main chip will run scorching hot.
Of course, it's also possible that one of the two (or both?) voltage regulators near C80 and C83 are malfunctioning or not outputting the right voltage. You could check the voltage to verify that. One should be outputting 3.3V (from a 5V supply) relative to ground - that would be U7 (voltage test point labeled "V33S" on PCB.) And the other (U8) should be making 1.8V relative to ground.

However, I still suggest you replace C80 and C83 first, along with as many of the other caps on the mainboard as possible, because bad caps can also cause those regulators to not work properly and any of the other issues too. So we need to get those crappy CapXon caps out of the guesswork.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

yea i was thinking of just recaping the whole board cause yea of those dam capxon caps all over it...

The first caps i replaced years ago think in 2014 which i had the fuzzyness and the brightness wouldn't move from 100 was rubycons but than again they came off a foxcon motherboard but they did last and really not sure if they died cause when the surge hit in 2018 and when the lights came back on all i had was a blue light no black light...

But yea the hair dryer trick does point to caps on the board cause that's what got the black light going again and got the color mode going. its just on a non going loop on that.

I will check the regulators in a couple hours and post the results.

Also what's a good place to buy caps? really dont want to spend to much cause if the caps dont fix the issue... Tho they would need replacing either way tho.

I found some on amazon which i had in my cart of all the ones i need but than i found out they made by chongx... which i herd is not great..

and yea LVDS connector is a bit worrying me:/ i mean i tested each pin from the connector to the main board and it checks out fine but yea idk.. what sucks you cant even get a replacement.. well so far no luck searching for it..

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

Ouch, those Amazon caps look horribly overpriced and garbage brand too. If they really are Chang/Chong/ +/-X, definitely stay away - those are as bad as cheap caps can be.

Try looking for the caps I suggested above on Digikey or Mouser. (Hint: to get to the correct search results, first make sure you're viewing only Electrolytic capacitors, then choose capacitance and voltage, then select the above listed brands only and look for the series I listed.) Since you only need a few caps, you can likely go with their cheapest shipping option, which should only run you a few $. The caps themselves will be in the 10-25 cent range at most.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Hmm i just noticed something... while i was looking for caps on those sites i figure i look once more at the board. and i noticed this.

should the V33S be missing the middle pin??? it also really don't look heathy either.

unless its suppose to be missing that pin?


Yea sadly i guess they was made that way with out that connected .. I search around for other boards on google and yea they are like that too...


I did noticed this guy on the mega thread for no power yesterday.

Hello
I have a screen hg281d down.
At the start, it cycle on red blue green.
I replace c80 & C83.
I do not have 1.8V to regulator vs18.
The output is short-circuited with ground.
The regulator is ok, the capacitor is ok.
I do not have the schema to find or is short circuit.
If anyone had the schema.


This is c82 was hs.
thanks.
now the screen turns on but there are red dots everywhere.
The tensions are good.
An idea?


If he means At the start, it cycle on red blue green. meaning the screen not the power led even tho i think the power led ony does blue and red. It kinda seems like thats what im getting but mine goes threw red blue green than greys than repeats non stop.

Tho i dont really under stand the c82 part? cause when i look i dont see anything next to c82 other than 2 solder joints?

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Got some voltage readings for the regulators.

while facing the 3 pins
v33s 1.55v right pin and left is 3.23v.

v18s is 1.49v right 1.76v left

This is when its on with the colors going on the screen. i assume those volts are close enough?


I noticed too even when you turn off the monitor fully but keeping the power plug in? the main board is still heated. Is that normal?


Also i looked up some caps and found theses.

Now the 10uf ones i could ony find ones that rated at 1000hours @ 105.

All the other ones are 5000 to 6000

so about 13-14$ total cause of shipping. Now im not sure if its worth getting all of them? Or just the bigger ones around the board and the c80-c83? I know its probably best to get some caps for the psu too tho im not sure if that's even a issue at the moment.

The LVDS connector still bothers me tho... Hate for it to be that along ... Tho it seems like you cant even find those :/ Did another test with the volt meter and all the pads is making a beeping sound back to the main board. And also tested it from the tcon board back to the main board each one makes a beep.

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

should the V33S be missing the middle pin??? it also really don't look heathy either.

unless its suppose to be missing that pin?

Yeah, that's how the part was made. The middle pin is also tied to the metal "tab" on the back. This is standard for just about every TO-252 component. So instead of using the middle pin, the regulator uses the metal tab for the electrical connection there. It provides better heat transfer from the device to the PCB.

Generally, for linear regulators like this, the PCB designer is supposed to leave a big copper plane on the board to which that tab gets soldered. This copper plane is then used as a heatsink for the device. Unfortunately, whoever designed this PCB made the size of the copper plane just big enough for the regulators to be operational, but not really big enough for them to cool well. So that's why it's important to have good quality caps there, because cheapo caps will otherwise cook and go bad again.

I did noticed this guy on the mega thread for no power yesterday.

Hello
I have a screen hg281d down.
At the start, it cycle on red blue green.
I replace c80 & C83.
I do not have 1.8V to regulator vs18.
The output is short-circuited with ground.
The regulator is ok, the capacitor is ok.
I do not have the schema to find or is short circuit.
If anyone had the schema.

This is c82 was hs.
thanks.
now the screen turns on but there are red dots everywhere.
The tensions are good.
An idea?


If he means At the start, it cycle on red blue green. meaning the screen not the power led even tho i think the power led ony does blue and red. It kinda seems like thats what im getting but mine goes threw red blue green than greys than repeats non stop.

That's likely some kind of built-in factory service test that has activated.
There should be a way to turn it off, but I'm not sure which key combinations of the menu buttons will achieve that.
If I had to guess, that service test most likely triggered from bad caps / excessive noise going to the main chip, causing it to act erratically.

Got some voltage readings for the regulators.

while facing the 3 pins
v33s 1.55v right pin and left is 3.23v.

v18s is 1.49v right 1.76v left

This is when its on with the colors going on the screen. i assume those volts are close enough?

Not sure if you took those readings right, though the 3.23V and 1.76V readings suggest the regulators might be OK (though the voltages do seem a bit off / low.)

If I remember correctly, those regulators were 1117 type... and if that's the case, then looking at the regulator with 3 pins on the bottom facing towards your body:
Left pin is Adjust/Ground (depending if it's an adjustable regulator or not)
Middle pin / large tab on the back is Output
And right pin is Input / Supply.

We really are only interested at the voltage on the Input and Output pins.

I noticed too even when you turn off the monitor fully but keeping the power plug in? the main board is still heated. Is that normal?

How hot? Burning/uncomfortable or just slightly warm? The former would be a bit concerning, though keep in mind it can take a few minutes for the main IC and regulators to cool down after the monitor is turned off.

Also i looked up some caps and found theses.

Now the 10uf ones i could ony find ones that rated at 1000hours @ 105.

All the other ones are 5000 to 6000

so about 13-14$ total cause of shipping. Now im not sure if its worth getting all of them? Or just the bigger ones around the board and the c80-c83?

Well, you could probably skip the caps around the audio amplifier IC (i.e. the SA7498L DIP chip) - which I imagine is what those 470 uF caps are for. But @ $1.41 total, just do them. One of these is likely providing filtering to a 12V line from the PSU. So if that line is noisy and possibly causing noise on the rest of the main board, this should help make it more quiet.

As for the other caps...
You can probably skip the 10 uF caps. Just get more 100 uF caps instead, like at least 10 of them. This will give you a price break on Digikey, so you'll be paying 20 cents a cap instead of 30... so 10 caps will run you just 50 cents more. Then use those extra 5 100 uF caps in place of the 10 uF caps. There's no harm in doing that. Just don't do this for the caps around the audio amp IC, as some of the smaller caps around it have a specific value for a reason. But on the rest of the board, it doesn't matter, as they are just filters. So the extra capacitance would actually be a good thing. Here are a few alternative part numbers for the 100 uF caps that will also do the job and are cheaper:
25YXJ100M5X11 (Rubycon YXJ, 25V, 100 uF)
25YXF100MEFCTA6.3X11 (Rubycon YXF, 25V, 100 uF)

Also, for C80 and C83, I suggest even going with 220 uF caps. The bigger their case size, the better too, as then they can dissipate some of the heat in the area with their body. So something like 16YXJ220MT16.3X11 or 16ZLH220MEFCT16.3X11 should be good.

Rubycon is very high quality, so I'd trust them to last there for a good time. And they are quite cheap right now.

I know its probably best to get some caps for the psu too tho im not sure if that's even a issue at the moment.

Post a picture of it.
Only if there are any non-Japanese brands in there I'd consider replacing them. Otherwise the usual PSUs that come with this monitor usually have United Chemicon KY/KZE on the output, IIRC, and those are really good too.

The LVDS connector still bothers me tho... Hate for it to be that along ...

Well, the fact that you can properly see the RGB colors from the service test mode without issues means the main board is able to send signals properly to the T-con. So I think that eliminates the LVDS connector as a cause for any of the issues. And you verified the connections, so I think that's further reassuring it is OK.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Got some pics of the psu. yea does seem like it uses good cap brands from what i see.


I tested the voltages again for the regulators. And the middle pins while touching the large tab its ony getting 0.08-0.04-0.14 at times for both regulators.

The left pin of the v18s 1.80-1.9v at times. right is 1.40-1.50sv for some reason the voltages are different than yesterday when i tested them..

v33s is about the same 3.33-3.40s left and 1.5-1.62v right. again difference from yesterday...

And i tested the temps again. while on the middle big chip and the regulators are hot and can ony keep your fingers on them i say about 5secs? might be normal sense these monitors i herd run super hot.

And this is what worry's me.. Turning the monitor off no light but still plugged in its still hot. So i tested the regulators and yep they still getting the same voltages as when on.... Unplug it and plug it back in to reset it and yep still the same voltages...

Kind of tells me there's something that might be wonky with the psu too with the mainboard

Idk could be the caps on the main board throwing the psu off too..

Probably best to just order those caps and see if that changes anything with the main board and hopefully that fixes the issue if not i guess the psu is the fault?


Yea i looked for the combo for the service mode menu and found a source that its the menu button and the adjust button below it. Holding both of them down will get you in it but yea in my case nothing pops up really none of the buttons does anything except the power button lol nor does any menu like even for volume settings or even the menu itself comes up.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

update just ordered the caps with the ones you suggested total was 9.89$ so really ony a 10$ lost if it still has a issue worth it in my opinion if it gets it going or get the cap issue on the main board out of the way lol

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

Got some pics of the psu. yea does seem like it uses good cap brands from what i see.

For the most part... yes.

But right from the first picture, I see a cap with "TK" on it. Those are not good. The Ltec caps seen here:
https://www.badcaps.net/forum/attach...6&d=1602589534
an here:
https://www.badcaps.net/forum/attach...5&d=1602589534
should also be replaced. They fail a lot too.

But since I already see you placed your order... just check that the PSU is outputting correct voltages. Go through the first few pages in that Hanns-G HG281D mega thread and check the PSU voltage outputs - particularly the standby section. IIRC, it should be 5V output.
*EDIT*
Post #2, question #2 by retirdercaps in that thread reads:
"2) If you have a multimeter, check the secondary voltages on the connector between the power board and logic card. You should get 5V DC at least one of the pins."

I tested the voltages again for the regulators. And the middle pins while touching the large tab its ony getting 0.08-0.04-0.14 at times for both regulators.

The left pin of the v18s 1.80-1.9v at times. right is 1.40-1.50sv for some reason the voltages are different than yesterday when i tested them..

v33s is about the same 3.33-3.40s left and 1.5-1.62v right. again difference from yesterday...

What are you using as ground?

The 3.3V regulator can't output 3.3V without a voltage on its input that is higher than the output.

And i tested the temps again. while on the middle big chip and the regulators are hot and can ony keep your fingers on them i say about 5secs? might be normal sense these monitors i herd run super hot.

With the monitor off / standby, the main chip shouldn't be getting that hot.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Yea im kind of kicking my self right now ordering too soon which 30mins after i did it i thought to myself maybe i should've wait to see if the psu needed caps.... lol

Ehh if i need more caps i don't mind spending a bit more. Hell i almost spent 18$ on those amazon caps which would've been a big mistake lol..

Will check the psu voltages tonight and see what they bring up.


For the regulator i use the big tab on the rear for ground. Unless that's the wrong way testing them?


And yea being in standby let alone being fully off it shouldn't be even getting warm... Which tells me there's probably something going wonky on the psu too...

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

k did the voltages from the psu connector 6 pin and the 3 pin going to the mainboard.


when its off and plugged in.

3pin

Red is 4.89v to-4.90v black is 0.

When its on its red 2.98v-3.00v. black is 4.70v

the 6pin reads. when off just the red wire is getting 4.92v

when on black wire 3.11v brownish is 0.03v green is 5.11v red is 4.85v and i think the next one next to it is orange? that's 0.02v and than yellow is 11.97v.


Than i redid the readings on the regs.. cause yea i did it wrong .... lol sorry...

i used the ground screw hole and this is what i get on them now.


When off v33s reads 4.89v right pin-- big tab reads 3.28v-- middle pin reads 3.28v

v18s reads 3.28v right---- 1.80v big tab--- 1.80v middle pin.


Now when on. v33s 4.78v right---3.26v big tab--- 3.26v middle pin.

v18s right 3.26v---big tab is 1.78v----middle is 1.78v.

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

Seems like the voltages are all in order, or at least as far as multimeter can tell.

While the 5V standby line is in spec, I was hoping it would be closer to 5V and maybe a few mV over instead of 4.85-4.95V. So that may or may not be something to be concerted. I guess we can wait for the main board caps to arrive and then see if anything changes after the recap. If not, then we may try the PSU caps...

And yeah, when measuring voltages, always use a known good ground as your reference (i.e. where you connect the black probe on your multimeter.) The exposed pads around any of the screw holes on any of the PCBs are one good place for that, like you did.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

Yea i should be getting the caps sat from what it says so i guess we see if those will get it back and going well i hope it does lol..

And yea i figured i was doing something wrong with the ground while testing for the regulators i thought the tab on the rear of it was the ground lol.. But yea i never tested a regulator before hehe.


I just find it weird why the main board is still getting power at least to the regulator and the main chip when its turn off.. Would any of the caps be causing that on the mainboard telling the psu to send power always?

kind of tell me that's a psu fault but yea everything does check out on the voltages from it to the board.

But best to wait and see after the mainboard gets capped than go from there to get that out of the way.

[momaka]

Re: Hanns-G HG281D stuck on self test color mode?

The main board (and those regulators on it) gets power all the time, because the main chip on it not only controls/processes video inputs, but also button inputs, menus, and On/Off controls. Thus, it has to be powered on all the time.

The main difference between the monitor being in On and Off/Standby, of course (at least on the logic board), is that the IC has no input video signals to process, and thus should be using a lot less power and running fairly cool.

[gordesky1]

Re: Hanns-G HG281D stuck on self test color mode?

The main board (and those regulators on it) gets power all the time, because the main chip on it not only controls/processes video inputs, but also button inputs, menus, and On/Off controls. Thus, it has to be powered on all the time.

The main difference between the monitor being in On and Off/Standby, of course (at least on the logic board), is that the IC has no input video signals to process, and thus should be using a lot less power and running fairly cool.

Oh i see yea that does make sense than. Maybe why its running so hot even when off its the caps throwing everything off.

Im hopeing thats the case anyways hehe