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Test Equipment Anonymous (TEA) group therapy thread
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bd139:
Will probably clean up fine. Insides however, hmm.
mnementh:

--- Quote from: Vince on July 06, 2022, 05:22:59 pm ---
--- Quote from: mnementh on July 06, 2022, 05:12:22 pm ---
--- Quote from: Vince on July 06, 2022, 04:04:32 pm ---TV REPAIR


--- End quote ---
So this panel is actually designed to be able to service the LED BL array...?

HALLE-FUKKIN-LUJAH!!!

These LED arrays are driven CC in series; they separate them in banks and modulate the drive current to different zones of the screen for higher "dynamic contrast" compared from one part of the screen to other parts. I'd guess that the two banks on each side drive alternately to be able to keep dwell time lower; either that, or each bank is aligned with a different diffraction lens so it corresponds to a different quadrant of the screen.  :-//

mnem
https://youtu.be/YrLk4vdY28Q
--- End quote ---


Well no, sorry to disappoint !  :-DD

You must have misunderstood me.... it is just as unserviceable as the older TV I worked on. In both cases you have to crack the screen apart, peal every layer of the "sandwich", and disconnect and remove off course the LCD panel itself... which is the dangerous / tricky part.

Also in both cases the strips are held with freaking double sided sticky tape which is a nightmare.

This TV, is even worse because the strip is stuck against its heat sink, there is very limited access to get tools, unlike the older TV with the strips laying flat on the chassis, so you had ample access from all sides to pry the strips off of the chassis.

So no, sorry Dragon... still a bunch of crap I am afraid !  :(

I will call it serviceable when you can replace the strips without having ti remove / disturb the LCD panel. That is, put the strips OUTside the frame, not inside.....  ::)
... and when the strips are also fixed with screw or any method designed to be easy to get off... so no glue or tape thanks...

Of course this will never happen... at least not on consumer stuff... maybe professional fancy expensive screens are built better, I don't know...

--- End quote ---

Awww, ma-a-a-an.... I saw that aluminum panel right there and imagined that somebody had come to their senses.  :P Of course, they just made it look like you might be able to work on the fuxxoring thing with some level of sanity...

Fuck you, Samsuck... it's just like Lucy and that fucking football again...    :palm:

mnem
mnementh:

--- Quote from: Vince on July 06, 2022, 06:48:13 pm ---
--- Quote from: Specmaster on July 06, 2022, 04:24:34 pm ---
--- Quote from: Vince on July 06, 2022, 04:04:32 pm ---TV REPAIR


--- End quote ---
Make sure if you are able to resurrect the other strings, that your friend is well aware that he might actually spot areas of his screen that are dimmer than others, in the areas with the dead LEDs, otherwise he might not be happy with you. Short of replacing all the strings, I can see no way around that problem. Great work so far, keep it coming.

--- End quote ---


Well yes if I manage to fix the thing I will see if the lighting is even enough to be acceptable, i fnot will tell him what he wants to do.

Hopefully there WILL be dark spots and he will tell me OK fuck you can keep it... more spare boards/parts for Vince !  >:D

We shall see.

I don't know where to buy the strings nor how much that costs. If it's available for this particular TV, and is ridiculously cheap including shipping... like 20 Euros shipped, and given the TV is recent, maybe he will want to pay for that. We are not there yet....
--- End quote ---

Why the eff would you trash an obviously repairable TV like that? Just put it away and wait for a paycheck so you can buy some LEDs for Ifni's sake. You really should replace those LEDs anyways, even if you are sending it back to the owner. Just jumpering them out is begging for all the others in the string to fail prematurely.

Correct repair, short of replacing them all, would be to measure voltage drop across every LED with them lit up and replace any that read appreciably lower or higher than the average. That would be your best chance to avoid recidivism. You already have a cheap hot-air rework station, right?

mnem
 :-/O
Vince:

--- Quote from: mnementh on July 06, 2022, 07:22:41 pm ---
--- Quote from: Vince on July 06, 2022, 06:48:13 pm ---
--- Quote from: Specmaster on July 06, 2022, 04:24:34 pm ---
--- Quote from: Vince on July 06, 2022, 04:04:32 pm ---TV REPAIR


--- End quote ---
Make sure if you are able to resurrect the other strings, that your friend is well aware that he might actually spot areas of his screen that are dimmer than others, in the areas with the dead LEDs, otherwise he might not be happy with you. Short of replacing all the strings, I can see no way around that problem. Great work so far, keep it coming.

--- End quote ---


Well yes if I manage to fix the thing I will see if the lighting is even enough to be acceptable, i fnot will tell him what he wants to do.

Hopefully there WILL be dark spots and he will tell me OK fuck you can keep it... more spare boards/parts for Vince !  >:D

We shall see.

I don't know where to buy the strings nor how much that costs. If it's available for this particular TV, and is ridiculously cheap including shipping... like 20 Euros shipped, and given the TV is recent, maybe he will want to pay for that. We are not there yet....
--- End quote ---


Why the eff would you trash an obviously repairable TV like that?
--- End quote ---

I don't want a TV, I don't watch TV, and even if I did, I would not want this particular one, way too big for my house, looks crap and ugly. Like all TV's.


--- Quote from: mnementh ---Just put it away and wait for a paycheck so you can buy some LEDs for Ifni's sake.

--- End quote ---

You mean so I can sell it to make money ? Depends how much it's worth on the second hand market, why not... but still, why wast emoney on new LED strips if it looks good enough as is to be flogged.
Plus, from a moral point of view, I don't like the idea of making money from something that was given to me. If I fix it, it's to give it back to the owner.



--- Quote from: mnementh ---You really should replace those LEDs anyways, even if you are sending it back to the owner.

--- End quote ---

Again not my call, not my TV. I don't get to make decisions, the owner does.
If he is happy the free repair and doesn't want to spend money to replace LEDs, it's his wallet and TV, he does what he wants.
All I can do is give him the information so he can make an informed decision, of course.


--- Quote from: mnementh ---Just jumpering them out is begging for all the others in the string to fail prematurely.
--- End quote ---

Yes. And even if I replaced the faulty LED's, the other would probalby start failing as well anyway....
so you replace the LED strips, costs money... then you don't know the quality that you will get, they might fail anytime as well.
And if they don't, then the power board will go bad because of caps or any of the numerous power transistors or diodes.

You never see the end of it, by the time you have fixed it 4 times in 2 years, you could have bought a brand new TV with a warranty.

It's just like what you said with old cars !  >:D



--- Quote from: mnementh ---Correct repair, short of replacing them all, would be to measure voltage drop across every LED with them lit up and replace any that read appreciably lower or higher than the average. That would be your best chance to avoid recidivism. You already have a cheap hot-air rework station, right?

--- End quote ---

Yes I have the cheap one everyone used to buy a few years ago, with the fan in the hand piece....
Replacing only the 2 individual defective LEDs you mean ? OK would do if I had appropriate LEDs on hand, but I don't.
Well maybe I could see if it's technically possible to use the ones I salvaged from the other TV, could have a look at that.
Efficiency/ brightness and colour temperature would of course not be the same, but maybe similar enough that it would be a better alternative to no LEDs at all... don't know.

First, try to fix the damn thing, get all 4 four strings working, then put the "light pipe" and reflector back into place to see if there are dark spots or if it's acceptable as is (old TV with 5 dead LEDs was just fine, incredibly enough....)

Then I will take it from there. One step at a time, one step at a time...  ;)

factory:

--- Quote from: m k on July 06, 2022, 03:18:44 pm ---
--- Quote from: mnementh on July 05, 2022, 10:52:01 pm ---
--- Quote from: m k on July 05, 2022, 07:49:36 pm ---
--- Quote from: mnementh on July 05, 2022, 01:45:40 pm ---...Yeah, 625 line PAL is interlaced; I was thinking that when we were talking before.  :-+

That's another reason I decided to put a pin in this project; I'm waiting on the outcome of this eBay dispute. If I'm not keeping this turd, I think I'd much rather spend the time and brain power figuring out what went wrong with my fuckeroo UTG962E. And playing with my brand-new LeSiglent T3DSO2102.  :-DD

mnem
Never any shortage of things a tinkerdwagon needs to do...

--- End quote ---

I'm a bit interested how this scope thing finally is.
For now my guess is that this 313 vertical has nothing to do with PAL.

Is there possibly a military grade high resolution video system with small screens?
Just wondering from where HP got their idea.

Somebody should count those H-sync pulses.
625 is raw PAL and it includes blanking time.

Somebody should also adjust their scope monitor so that returning beam is visible and count how many H-lines it needs.
That much is needed over that 313.

Old Hitachi schematics has very clear horizontal timing as 41.2us.
Is it the right device for sure?

Only one google hit for CDU-10BA241, title of Hitachi schematics.
https://www.eevblog.com/forum/testgear/hp-871xb-vna-crt-module-capacitor-identification-help/

Much more for CDK-10BA242.
One of its CRT is 240ANB31N and earlier tube shuffle pays off.
As everybody remembers 31 is green, it continues so that 4 is white.
Tube in Hitachi schematics is 240ANB4(N).

Is this white CRT a rarity, is the whole input side of that schematics a rarity?
Maybe 546xx real H-sync is something else than 24270Hz.

--- End quote ---

According to the Wikipedia entry, there were several PAL standards; most operated at 625 lines(576 visible)50Hz while PAL M operated at 525 lines(480 Visible)60Hz. There was a "standard" called PAL-60 as well that allowed European VCRs to display NTSC VHS tapes; it was a bastard in that it misused the hardware by displaying PAL video at 60Hz with the NTSC color information, this was later promoted by video game consoles like the DreamCast.

I've read somewhere in the HP sales fluff that "waveform refresh" is at 60Hz, so I suspect it is something like that. OTOH, as they're using the PAL chip in a closed system, there's probably no reason they couldn't make their own "bastard" format at 625 lines(576 visible)60Hz...  :-//

As for where these monitors came from... they are small open-frame industrial monitors meant for all sorts of automated manufacturing applications; usually driven by some embedded computer.

mnem
I think. As always, take anything I say with a grain of salt big enough to pickle a dragon. ;)

--- End quote ---

All PALs are interlaced and 546xx is clearly not, or at least I've not seen a picture indicating different, there part of the picture would be dimmed or disarranged.
There's also D1-PAL, a possibly standard for digitized stuff and 720x576i, obviously not a full signal.

It's of course also possible that the scope has a crooked installation of things where composite signal is composed and taken apart inside the scope and only after that fed to monitor, since there are separated sync sync signals.
Never seen one but who knows, maybe it was a clever form of direct memory access and used chip exported all necessary signals.
On the other hand, maybe 313 is just a prank since one more or less doesn't mean a thing when the real one is 312.5 and license plate was already famous.

First stackexchange answer has a good picture of beam.
https://electronics.stackexchange.com/questions/98922/why-there-is-625-lines-pal-in-t-v-scanning-or-odd-lines/98926#98926

Good place for PAL specs.
http://martin.hinner.info/vga/pal.html
Good picture of field selection.
http://martin.hinner.info/vga/pal.gif

TI paper has exact scope screens.
https://www.ti.com/lit/pdf/sboa109

--- End quote ---

Where did the PAL picture standard discussion come from for this HP scope? the PAL chip on the 54645N scope mainboard (A3) is just a Programmable Array Logic IC, listed as A3U5 "IC DGTL PAL CMOS 1800-GATES 12NS", I did post the relevant diagram parts, not sure if anyone looked at them.  :-// Pixel data goes in and video data in the form of half bright & full bright pulses come out.

Horizontal & vertical sync pulses come from the A3U28 G-Array IC, these are 19.72kHz & 60Hz for the 54615B at least, I did verify this. I didn't check pulse width but could do, as it's still apart, waiting for some spare time to try & find the intermittent fault.

I doubt the Hsync/Vsync would be any different for the broken Agilent scope, but I suspect the video data is double given the increased specifications mentioned.

David
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