Hioki 3532-50 LCR Repair (One major problem solved, SM still wanted)

[KungFuJosh]

I had fixed the crack above the display with an adhesive that we also use for fixing components that are used in armored vehicles....I don't know if it would have been necessary to repair it again.

I fixed it because it was broken. 😉

[KungFuJosh]

This was the result of intensive irradiation with UV light and the use of hydrogen peroxide.
I can't imagine that a cream will give the same result.
Either way, the problem is more likely to be protecting the now white front from yellowing, because obviously the white doesn't last long.

The creme is hydrogen peroxide, but being a cream helps it hold in place on the plastic, and it goes in a bag to stop it from drying out. It might not accomplish more than what the previous attempt did, but it's worth a try while waiting for things to arrive from China.

What UV lamp did you use? I'd rather not leave it outdoors for a couple days if I don't have to.

[KungFuJosh]

First attempt went better than I thought. 🤣

In the youtube video I watched, the guy put the cream on with a brush. I was lazy and just lathered it on with my hand. I think the brush is better for a more even application, so I will do that for the next sunny day.

I left it outside for 8 hours, but I think maybe only 5 or 6 had sunlight. Next time I need to use the opposite hand railing; that one stays in the sun longer. Oops.

[Martin72]

Wow, just wow...

[KungFuJosh]

Some more progress. The screen looks nice, and the LED backlight indeed does not need separate power. It appears that both the contrast pot on the back of the LCD and the Hioki's contrast pot work.

There's one probably minor flaw, and that's that the cable is soldered to the back of the LCD's PCB. The cable gets connected without twisting, which is nice.

The LCD also seems to fit fine in the front panel.



Also, it was packed nicer than anything I've ever received from aliexpress. Double boxed, doubled padded, and double anti-static too.

[Martin72]

Judging by the stripes, you haven't adjusted its own contrast yet, have you?

[KungFuJosh]

Judging by the stripes, you haven't adjusted its own contrast yet, have you?

I'm talking to the seller now to deal with that. I've tried adjusting both contrasts, but it's hard to get a perfect balance. I think the cable connection is poor.

Interestingly enough, they also include an extra IC chip, which he told me to solder in to try and help with it. I soldered it in, and the dots look better at least.

[KungFuJosh]

The seller has been trying to rectify this, but of course I just got a message limit error from aliexpress. 🙄🙄 Try again in 24 hours. 💩 That blocked sending attachments, not the actual chat. Still annoying tho.

He had me remove the contrast knob on the back of the LCD, and then the chip he previously had me add. He said the IC chip was for negative pressure voltage related to contrast.

[KungFuJosh]

I was fairly convinced the soldered-in cable was part of the issue, so I removed it. Then I removed the cable connector from the old LCD, and installed it on the new LCD.



What was on the display improved a little, unfortunately though, I had to use the old cable which was also damaged. I ordered some new cables from Amazon, and I'm hoping that does the trick.



I also suspect that the contrast pot on the LCR should maybe be replaced. I might do that also. ETA: Nope. I pulled the pot and tested it, and it works fine. It felt a little loose before, maybe reinstalling it helped. I'll find out in a couple days when I get the new ribbon cables from amazon.

In any case, the seller has been helpful and quick to respond the whole time. This is the LCD I bought: https://www.aliexpress.us/item/3256802097838920.html

Thanks,
Josh

[KungFuJosh]

The touch panel I ordered arrived today. Totally useless, does nothing at all. Oh well. On to the next one.

[Martin72]

Fu...
However, even at the risk of you hitting me:
I almost went insane back then, as it now belongs around, the first time I plugged it in wrong, so that the contacts went empty (not occupied).

[KungFuJosh]

Don't worry, I had the same thought. 

The longer cable goes to the farther connector. But I plugged both cables in to both connectors, and even tried both ways again after flipping the new touch panel around so both cable connections were tried with both sides of the panel. It's junk.

Then I plugged the original stock panel in, and it still partially works.

The funny thing is, that the original panel works in one area, while the panel you tried to replace it with worked in a different area. The new one didn't work at all.

[Martin72]

What annoyed me was that there was no data sheet for the touch panel.
This is a resistor matrix, no “hard” commands are sent to the board through it, but voltage dividers are generated.
At least that's what I think with a resistive touch panel.
What I want to get at is that you can measure the panel to make sure that the error is not somewhere on the board (which I don't believe).
But you need to know how the pins are assigned.
Therefore.... data sheet.

[KungFuJosh]

There are 6 X and 6 Y traces, and there's some other weird stuff going on, like one line that circles the whole pad and maybe connects X and Y at some point. The common feature that I've seen so far is that they all suck. 😉

Finding a decent LCD screen was too easy, so I think the touch panel will remain a pain in the 🫏.

[KungFuJosh]

I just noticed something. If you compare the original to the common replacement versions, the replacements have an extra trace.

[zepto]

This is a nice LCR meter. Is it not possible to control it with GPIB? Seems like a lot of effort if there is an alternate interface available. An external interface would also allow you to plot sweeps.

[KungFuJosh]

It mentions external I/O in the manual, but doesn't specify any standards (that I saw in the 4 seconds I skimmed that section).

If it can be used remotely with something like TestController, that would be cool, but I'm not likely to use it if I can't get the touch panel to work. I think I will eventually.

[KungFuJosh]

Oh yeah, some dummy wasn't paying attention and bought new cables with .5mm pitch instead of 1mm pitch. Oops. The wait continues.

[KungFuJosh]

I scanned both sides of the original touch panel. You can see it's generally different than the other attempted replacements. One cable has six traces that apply to horizontal sense, and the other has 6 traces for vertical sense, plus one trace that goes all the way around and connects two pins.

Many of the replacements that don't work, have placed one of the horizontal sense points on the opposite side of the panel. I don't think this would work anyway, unless you knew how to recalibrate the touch panel.

Does anybody know how to calibrate these panels?

[zepto]

It mentions external I/O in the manual, but doesn't specify any standards (that I saw in the 4 seconds I skimmed that section).

If it can be used remotely with something like TestController, that would be cool, but I'm not likely to use it if I can't get the touch panel to work. I think I will eventually.

I understand, and I did not mean to be dismissive of your efforts. I meant the capabilities of this device aren't really exploited by the touch screen interface. It still has value, assuming an external interface is available, even if the display and touchscreen are completely broken. If you give up, do not throw it away.

I will have a 3531 soon. It is a couple revisions behind your model (3531->3532->3532-50) and has a GPIB interface. Assuming it isn't completely destroyed in shipping, I will write some programs for it. I can share them with you if you are interested.

[KungFuJosh]

I understand, and I did not mean to be dismissive of your efforts. I meant the capabilities of this device aren't really exploited by the touch screen interface. It still has value, assuming an external interface is available, even if the display and touchscreen are completely broken. If you give up, do not throw it away.

I will have a 3531 soon. It is a couple revisions behind your model (3531->3532->3532-50) and has a GPIB interface. Assuming it isn't completely destroyed in shipping, I will write some programs for it. I can share them with you if you are interested.

I didn't think you were being dismissive at all. I just doubt I'd use the device much if I can't get it working properly.

I would love to see what you come up with. Do you use TestController at all? It's a great program. If we could add support on there for these devices, that would be awesome.

[KungFuJosh]

I just got an original touch panel on eBay for $78 including shipping. It's lightly scratched, but works fully according to the seller. We'll see!

[Martin72]

I understand, and I did not mean to be dismissive of your efforts. I meant the capabilities of this device aren't really exploited by the touch screen interface. It still has value, assuming an external interface is available, even if the display and touchscreen are completely broken. If you give up, do not throw it away.

This Hioki has a RS232 slot (instead of GPIB), I have made a corresponding cable (25-pin to 9-pin).
It can be controlled with the software that can still be downloaded from Hioki, it even works with Windows 10 without any problems:
https://www.eevblog.com/forum/testgear/schematicservice-manual-for-hioki-lcr-3532-50/msg5238030/#msg5238030
The device “obeys” SCPI commands, so integrating it into the “Test Controller” software environment should not be a problem.

[KungFuJosh]

The LCD situation is interesting. It's obviously not terrible in the photos above, but it's not perfect either. The seller has been trying (along with the help of his engineer) to make it better. Today he had me remove R13, and jumper J26. That didn't help, so the engineer wants me to increase the resistor values of R1, R2, R4, R5 from 222 to 302. I had to order an 0805 resistor kit since I didn't have that value on hand, but I should have it tomorrow.

[KungFuJosh]

No improvements yet. It appears they were trying to improve the display quality by adjusting the contrast center point.

I figured that out quickly because I tried 3.3kΩ, and it was immediately too high contrast. Switched down to 3kΩ and it was adjustable again, but looked like the attached.

I asked them if there's something else that affects flickering or filtering we could change. Or if they have other ideas. 🤷