Author Topic: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)  (Read 15985 times)

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Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #150 on: August 29, 2024, 02:36:08 pm »
I could definitely live with it as it is if I was going to keep it, but I'm not. The next owner will need to live with it or make it better if I can't.

I think in person it already looks better than the original LCD. The ghosting can definitely be tweaked, but I had to return the resistor book I had. They were supposed to be 1%, but were more like 5% to 20%+. I ordered another book, and hopefully that one will be better.

I raised R3 to 100k, since that was the only higher value I had floating on my workbench, and that made everything besides the R1/R5 vertical lines basically disappear. When the new resistor book comes, I'm going to try lowering it. If I can make the general stuff darker without changing R2, then I think that may lead us somewhere better. R1/R2 definitely have a relationship that makes it impossible to tweak one area without affecting the other. I'm hopeful because the R3 change didn't appear to have any significant effect on the ghosting.

Thanks,
Josh
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Online Martin72Topic starter

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #151 on: August 29, 2024, 02:51:49 pm »
Have you ever tried to clean the original display, i.e. these “zebra stripes”?
I didn't trust myself to do that, so I preferred not to touch anything.

Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #152 on: August 29, 2024, 04:07:12 pm »
Have you ever tried to clean the original display, i.e. these “zebra stripes”?
I didn't trust myself to do that, so I preferred not to touch anything.

No, even if I somehow made that better, the lack of a backlight makes it not worth the time. I really like the idea of the modern LCD with the LED backlight anyway.

I'm pretty confident about R3 shifting this somewhere where I can get the contrast better without the ghosting. I'm going to try a pot, and hopefully it behaves. 😉 ...otherwise I need to wait until tomorrow when the new resistors should arrive.

ETA: A pot was useless, but alligator clips worked with THT resistors. Lowering R3 improved the general stuff, and had no effect on the ghosting. Still experimenting.

ETA2: R3 at 68k seemed improved, but then lowering R5 went wonky. I'll wait until tomorrow for the resistors to arrive.
« Last Edit: August 29, 2024, 06:19:38 pm by KungFuJosh »
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Online Martin72Topic starter

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #153 on: August 29, 2024, 08:45:28 pm »
Quote
No, even if I somehow made that better, the lack of a backlight makes it not worth the time. I really like the idea of the modern LCD with the LED backlight anyway.

LED lighting can be retrofitted there, see layout.
I'm really surprised that you have to tinker so much with a new display.

Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #154 on: August 29, 2024, 10:00:37 pm »
I'm really surprised that you have to tinker so much with a new display.

Me too. If I had to guess, I would say it's probably because the values the guy suggested were maybe not great. They said they borrowed "the same device" to test it with and it worked with those values, but they conveniently didn't take pictures, and they already returned the LCR. 🙄

When I get the new resistors, I'm considering going back to the original values and tweaking from there.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #155 on: August 29, 2024, 10:28:39 pm »
Hmmmmmmmmmmm. I started looking at some of the same LCDs from other sellers, especially on eBay. It seems they have less populated. 🤔

ETA: it looks like most of that "extra" stuff is related to U8. Without U8 I guess R7 - R10, L1, D1, etc. are useless.
« Last Edit: August 29, 2024, 10:37:12 pm by KungFuJosh »
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Offline coromonadalix

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #156 on: August 29, 2024, 10:57:00 pm »
maybe  because

on some systems,    the main board is providing the negative voltage,  had a few who needed at least -21 to -25 vdc  to have good contrast  ???

i managed to find some small tdk miniature smps  and fiddled soldered it on the glcd ...

what annoys me is:   when they say "compatible"  and they don't provide what you need to make them work
 
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Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #157 on: August 29, 2024, 11:12:41 pm »
Yeah, if I understood anything about how LCDs work (don't really want to 😉) then maybe tweaking the "negative pressure" BS might be helpful. I dunno. It didn't really have any effect whether it was active or not regarding the ghosting anyway.
"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

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #158 on: August 30, 2024, 09:47:35 pm »
If you compare the two displays, you will notice the complete absence of the “fat” capacitors in the original, even if there are corresponding assembly options available.

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #159 on: August 30, 2024, 11:44:15 pm »
Good news, and bad news.

The bad news: the new LCD basically decided to get cuckoo last night. It's probably useless, and will most likely get returned.


The good news: I found a touch panel that works! There was no data before because I apparently managed to set the trigger to external. 😉



"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #160 on: August 31, 2024, 12:12:09 am »
Quote
The good news: I found a touch panel that works!

Yeah ! :-+


Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #161 on: August 31, 2024, 12:16:20 am »
Quote
The good news: I found a touch panel that works!

Yeah ! :-+

I'm pretty happy about that. That seemed to be the harder thing to find.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #162 on: August 31, 2024, 01:46:50 am »
The seller I bought the touch panel from also sells a very similar LED backlit LCD panel, and actually advertises it as being for the Hioki 3532-50. I sent him an offer, I'll probably wind up getting it from him. I'm interested to see if it works 100% or has similar issues.

ETA: Ordered.
« Last Edit: August 31, 2024, 02:19:45 am by KungFuJosh »
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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #163 on: September 05, 2024, 06:58:09 pm »
I only have a minute, so I'll just throw this right here...

"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #164 on: September 05, 2024, 08:26:47 pm »
For anybody who needs a new touch panel or LCD, goldenworld8811 is the seller on eBay I got both from. When I ordered the LCD, they asked me to send photos of the front and back of the original LCD. The LCD they shipped is not the same as pictured in their ad, but actually matched the look/bezel of the original better. It's also a modern backlight, which is nice.

LCD: https://www.ebay.com/itm/153333452030
Touch Panel: https://www.ebay.com/itm/163477240213

As always, my experience was good, but YMMV.

Thanks,
Josh
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
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Online Martin72Topic starter

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #165 on: September 05, 2024, 08:33:23 pm »
That looks very good now. :-+
Are you going to leave it as it is and deal with the device itself?
 
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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #166 on: September 05, 2024, 08:45:12 pm »
Thank you, yes, it's great as it is.

It's got the internal contrast control (I swapped with a 10k as it was supposed to be). I doubt it should need to be adjusted with this LCD panel anyway. I tried contacting the manufacturer of the original pot, but never heard back. From the pot case to the end of the shaft is 35mm, and I couldn't find anything that is both a 9mm pot and that long. So I'm over that. I used some double-sided tape to mount the knob so it doesn't look goofy. Another option was to put something goofier there, but I opted not to since I'm not gonna keep it.

It's already warmed up, so I'm doing open/short correction now and I'll see how it compares with the LCR Cal Test PCB. I'll post the results in that thread when I'm done.

Thanks,
Josh
« Last Edit: September 05, 2024, 09:17:23 pm by KungFuJosh »
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
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Online KungFuJosh

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Re: Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)
« Reply #167 on: September 05, 2024, 11:10:14 pm »
Here's a couple more photos. The screen zoom feature is cute. I posted the test results in the Cal Test PCB thread.
"Right now I’m having amnesia and déjà vu at the same time. I think I’ve forgotten this before." - Steven Wright
 
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