Author Topic: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)  (Read 15994 times)

0 Members and 1 Guest are viewing this topic.

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #100 on: August 22, 2024, 07:00:35 pm »
Do you have a data sheet for the display?
It also looks like information is missing on the left, which can't be due to the contrast.

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #101 on: August 22, 2024, 10:52:34 pm »
I don't. I might ask for one. Though I might have set something weird when messing with different touch screens. 🤷

ETA: I'll add a connector back to the original LCD and see if it's any different if the touch panel takes too long to get here.
« Last Edit: August 23, 2024, 03:58:00 am by KungFuJosh »
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #102 on: August 25, 2024, 02:29:43 am »
Here's the original LCD connected. No data showing there either. The contrast looks great though. 🤷
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #103 on: August 25, 2024, 03:17:34 am »
The LCD seller said the engineer should have a Hioki to test the LCD on in a few days. Hopefully, he'll get what he needs out of that to tell my dumbass what to change to make this work properly. Otherwise, I'll need to return it and get the old style LCD instead.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #104 on: August 25, 2024, 12:54:58 pm »
Here's the original LCD connected. No data showing there either.
That was my mistake, if no parameter was selected (“off”), then nothing else is displayed, which also makes sense.

 
The following users thanked this post: KungFuJosh

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #105 on: August 26, 2024, 03:49:03 pm »
Progress?

Their engineer suggested the following changes:

R1 392
R2 472
R3 823
R4 622
R5 392
R6 822

Unfortunately, the resistor kit I bought was limited, and I don't have the 39, 62, or 82 variants. So I tried with 33, 56, 75 instead.

This is what it looked like:


I also replaced the 10k pot on the PCB with a 25k trim pot. The original pot was mechanically unhappy. It's more stable now with the trim pot. I might try and find the replacement 10k pot, but, eh, I don't know if it's worth the effort.

Since the change made some improvements, I tried changing R4 to 7.5k and that helped horizontally, but not vertically. So I tried changing R3 to 100K, and it was too much. Now I'm ordering a better resistor kit to put the suggested values in. I'm much more confident in the possibility of this working now though.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #106 on: August 26, 2024, 04:23:25 pm »
I screwed around some more, and it got a little better:

Suggestions -> substitutions:

R1 392 -> 4.7k
R2 472
R3 823 -> 100k
R4 622 -> 7.5k
R5 392 -> 4.7k
R6 822 -> 10k

I might try a 5.6k at R2. I ordered the resistor set, but that doesn't come until tomorrow. 😉

The 25k trim pot is useless with those values. It has be set to contrast fully on to see what's there. I know I have other trim pots...somewhere.

I'm guessing/hoping that tomorrow with the correct values, everything will look betterer.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #107 on: August 26, 2024, 05:26:37 pm »
This is getting interesting. I changed R2 from 4.7k to 5.6k, and it shifted the contrast center so that the trim pot became useful again. The image still wasn't great, so I increased it to 7.5k and we have better contrast, and more usable range on the trim pot.

However, that shifted a vertical section out:


Since I'm guessing, and don't have a schematic or datasheet to go from, I'm going to experiment with R4 next and see what happens if I increase that value.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #108 on: August 26, 2024, 06:19:15 pm »
After some more experimenting, it looks pretty good!



Here's my current R values:

R1 5.6k
R2 7.5k
R3 100k
R4 5.6k
R5 7.5k
R6 10k

I'll ask the seller to ask the engineer if he thinks that can be improved upon.

Thanks,
Josh
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
The following users thanked this post: Martin72

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #109 on: August 26, 2024, 07:25:41 pm »
Could you please take a good photo of the board side of the new display?
 
The following users thanked this post: KungFuJosh

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #110 on: August 26, 2024, 08:18:17 pm »
Sure, but please ignore my sloppy soldering. I was experimenting at high speed. 😉

Here's the changed areas from the original:
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
The following users thanked this post: Martin72

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #111 on: August 26, 2024, 08:46:28 pm »
You could ask the supplier for a circuit diagram, he should have one.
In the meantime, the contrast thing has become clearer to me, the corresponding potentiometer on the Hioki should no longer have anything to do with the actual background lighting.
The potentiometer will go to pin13 in the original display.


Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #112 on: August 26, 2024, 09:03:59 pm »
You could ask the supplier for a circuit diagram, he should have one.
In the meantime, the contrast thing has become clearer to me, the corresponding potentiometer on the Hioki should no longer have anything to do with the actual background lighting.
The potentiometer will go to pin13 in the original display.

Contrast doesn't affect the background lighting at all. Contrast affects the darkness of what's on screen. For example, in the attached (outdated) images, the LCD brightness is unchanged. Only the contrast is changed. It was either too light or too dark with no middle ground where the image on the screen looked good.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #113 on: August 26, 2024, 09:06:32 pm »
Quote
Contrast affects the darkness of what's on screen.

That's what I wanted to say.
 
The following users thanked this post: KungFuJosh

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #114 on: August 26, 2024, 09:30:09 pm »
I had a feeling it was a 'lost in translation' thing. 😉

I'm hoping to improve the result a little more, but if where it is is the best I can do, I'd say it's good enough.

I got the next replacement touch panel today. Junk. The seller lied about it, and now I get to deal with that and try to find something better.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
The following users thanked this post: Martin72

Online Martin72Topic starter

  • Super Contributor
  • ***
  • Posts: 7017
  • Country: de
  • Testfield Technician
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #115 on: August 26, 2024, 09:39:40 pm »
A circuit diagram would be helpful, try your luck with the supplier...
I'm a bit surprised at the moment that it's such a “problem” to display the characters properly.

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #116 on: August 26, 2024, 10:04:47 pm »
I was surprised at first as well, but I'm not anymore. Hioki clearly designed it a specific way with a specific LCD panel, and getting a modern LCD to match that isn't as straight forward as I thought. At least not for whatever this LCD was designed for.

I already asked for a schematic and they said they didn't have one. Which might might mean "they don't have one they'll share." 🤷
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
The following users thanked this post: Martin72

Offline coromonadalix

  • Super Contributor
  • ***
  • Posts: 6998
  • Country: ca
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #117 on: August 26, 2024, 10:48:34 pm »
all theses resistors things must play with duty cycle, timings  etc ...   it's a matter of finding the row and column drivers data sheet if they exists and try to figure out   ...
 
The following users thanked this post: KungFuJosh

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #118 on: August 26, 2024, 11:15:15 pm »
all theses resistors things must play with duty cycle, timings  etc ...   it's a matter of finding the row and column drivers data sheet if they exists and try to figure out   ...

Exactly. Here's my notes so far:

R1 392 -> 4.7k -> 5.6k (increase shifted contrast center further after adjusting R2)
R2 472 -> 7.5k (better contrast center / more range with trim pot)
R3 823 -> 100k
R4 622 -> 7.5k -> 10k (bad - more flicker) -> 5.6k (less flicker)
R5 392 -> 4.7k -> 5.6k (vertical lines partially returned) -> 7.5k better!
R6 822 -> 10k
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #119 on: August 27, 2024, 02:37:08 am »
I just ordered another touch panel from eBay (already got a refund from the junk one). This one is supposedly new, and the trace pattern looks more like the original.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #120 on: August 27, 2024, 03:30:05 am »
I don't know if I'll bother replacing the original pot or not, but if anybody else needs one...

It's from ALPS, 10kΩ, and appears to be from their RK09L series (or at least very similar). However, it's a 35mm shaft, and 3B taper.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #121 on: August 27, 2024, 09:57:33 pm »
I got a better resistor book in today, and tried the engineer's suggested values. They were worse than what I came up with. I tweaked the values a bit, and now I'm about where I was before as far as it looks.

This was today:
R1 392
R2 472 (not enough contrast range) -> 5.6k (better)
R3 823
R4 622 -> 5.6k (better but still a little flicker) -> 4.7k (better)
R5 392 -> 7.5k (too much Vertical line contrast) -> 5.6k (too much? has Vertical ghosting) - 4.7k still some minor ghosting but better
R6 822

I asked the seller to ask the engineer the specific function of each resistor so I can stop guessing on the others. Hopefully, he actually gets me that info.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #122 on: August 27, 2024, 09:58:52 pm »
This was with the suggested values. It looks better in some ways besides the glaring issue. If I knew all the specific functions, it might actually come out well. 🤷
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #123 on: August 28, 2024, 04:13:22 am »
I don't know if it's interesting, or annoying, but there's clearly a relationship between R1 and R2. Nothing looks better than R1 at 2.4k with R2 at 6.8k, but R1 at 1.2k with R2 at 7.5k is very close. In either case, the bottom right corner fades out.

With R1 at 2.4k and R2 at 5.1k, those vertical lines looked better, but the rest looked like crap.

R2 also shifts the contrast center, so there's more adjustable range with the contrast knob when R2 is higher. But the higher R2 goes, the more it screws up the verticals controlled by R1.

I think / hope that one of the other resistors has an effect on the relationship of R1 and R2.

R4 value has an effect on the flicker. I didn't notice any other changes when I adjusted R4.

R3 and R6 I have no clue about, but when I tried to change R6 it had almost no effect using a pot.

R5 previously did affect the vertical lines. I'm going to tweak that next and see how it goes. 🤷

Right now I have:

R1 1.2k
R2 7.5k
R3 82k
R4 4.7k
R5 3.9k
R6 8.2k
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Offline KungFuJosh

  • Super Contributor
  • ***
  • Posts: 3160
  • Country: us
  • TEAS is real.
Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #124 on: August 28, 2024, 04:26:33 am »
R5 definitely improved the situation. I don't know if I want to tweak it anymore. I might try 5.1k if I get bored.

Current values:
R1 1.2k
R2 7.5k
R3 82k
R4 4.7k
R5 4.7k
R6 8.2k
« Last Edit: August 28, 2024, 04:33:59 am by KungFuJosh »
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
The following users thanked this post: Martin72


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf