Kawai K1r LCD View angle? Any owners out there? (resolved)

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Kawai K1r LCD View angle? Any owners out there? (resolved)

Postby part12studios » Mon Feb 06, 2017 10:38 pm

Hi everyone,

I have recently got my hands on a K1r and one thing I've noticed is that the thing has a view angle that is only visible when looking downward. the screen looks good at that angle.. but you can't see it straight on or looking up..

that said i'm used to most devices i have from that era having some kind of system setting to change the viewing angle and I can't seem to find any mention of it in the manual.. there is no knob / pot to speak of. i opened it up to see if it was hidden somewhere.. i'm stumped.

I can't imagine the unit was really made to be locked to a downward viewing angle. The prior owner doesn't know anything about it.

Thanks!
Caleb
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Mon Feb 06, 2017 10:59 pm

That would be pretty ridiculous to not have an adjustable contrast, at least at the factory. It seems like there has to be a variable resistor on the mainboard somewhere.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Esus » Tue Feb 07, 2017 12:06 am

Mine does the same thing. Maybe it's a Kawai feature...
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby part12studios » Tue Feb 07, 2017 1:54 am

@esus that's "good" to hear.. feature indeed.. i mean thinking back the K1m I don't think had the adjustment either, but it seemed like it was at least centered as you'd expect. maybe it shifts with age or something on some devices.

@rasputin yes that's exactly what I'd think too.. there must be a way to adjust the angle.. but I have no clue where I could make such a change.

I guess I just need to move it down low so it's easier to see.. or trade back.. on the fence on that one.. might trade back just because fack.. it's annoying.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Tue Feb 07, 2017 2:11 am

Well... if you're ambitious then you can follow the VO pin on the display back to the mainboard and see if it's connected to a fixed resistor or if it is connected to a trim pot. If it's the second case, problem solved. If it's the first case then rig one up and make your own contrast adjust.

If it's a classic Hitachi display (good chance) then it should be pin 3 of the display. If it is connected to ground then you should have max contrast. Keep upping the voltage anywhere from 0V to 5V to taste.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby part12studios » Tue Feb 07, 2017 3:21 am

I'm going to reopen it and give that another closer look. I didn't really look for pots and in hindsight that was shortsighted of me. I am confident there must be a tweakable solution already in it. the fact that you can't see it looking straight at it tells me something was modified.. and the screen is bright and strong.. which given it's age is saying something.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Esus » Tue Feb 07, 2017 3:47 am

Keep us posted!
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Alex E » Tue Feb 07, 2017 5:34 am

The Yamaha TX802 and TX16w has the same issue. Real annoying but probably standard fare for the time.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Tue Feb 07, 2017 6:43 pm

Alex E wrote:The Yamaha TX802 and TX16w has the same issue. Real annoying but probably standard fare for the time.


I'm not going to argue that this doesn't occur on a significant percentage of those machines, but I have both a TX802 and a TX16W that has a perfect straight on viewing angle with a little up/down leeway. I'm only bringing that up so no one thinks all of them came from the factory like that, or that it's some insurmountable problem inherent to those devices.

You too can have a properly displaying LCD :)
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Tue Feb 07, 2017 6:49 pm

part12studios wrote:I can't imagine the unit was really made to be locked to a downward viewing angle. The prior owner doesn't know anything about it.


I'm assuming that it looks too washed out when viewed head-on or from a low angle. If so, that should indicate the voltage is slightly too high. Measure the contrast pin and see if it's up at +4.9-5.1VDC or so. Usually the sweet-spot is in the 4.4V range, so my guess is you'll need to lower the voltage.

If it has an adjustable trim built-in (can't find schematics and don't own own to check!) then it will very likely look like a really short plastic "screw" that's eager for a Phillips head.

A picture of the display header from both the display and mainboard side might be helpful. Heck, the component side of the entire mainboard couldn't hurt either.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby part12studios » Tue Feb 07, 2017 6:59 pm

@rasputin yes at the right (looking down) angle it's clear but yea straight on is bad..

I like your idea.. so you think this would be something i could run by an electronic repair person to request? say have them put some kind of pot on the 3rd wire.. intercept it and then tweak the pot to adjust to taste? Sounds pretty doable even for someone not specifically used to music equipment like this.

So yea it is interesting.. if it were going to a resistor.. it makes sense that if the resistor went "bad" then that would mean max voltage is going to it spiking the angle to max.. i love the idea of getting a pot installed to tweak and even have it mounted on the back or something to be easy to adjust in the future. I'll have to see what the cost might be.. still tempted to just trade back for my K1m though which had nice buttons and no viewing angle problem at all.. just awkward shape for my studio..

I opened it up again and took a closer look for pots or other signs of tweakage and nothing but i did take some pics in case anyone saw something promising that i overlooked.

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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Tue Feb 07, 2017 7:09 pm

part12studios wrote:I like your idea.. so you think this would be something i could run by an electronic repair person to request? say have them put some kind of pot on the 3rd wire.. intercept it and then tweak the pot to adjust to taste? Sounds pretty doable even for someone not specifically used to music equipment like this.


It's pretty much as simple a mod as there could ever be.

There are a couple ways to approach it. Snip one wire, try a few good-guess resistor values until you get proper contrast, done. Or do the adjustable pot thing which isn't much more complicated. You'd take +5V and ground, connect it to the pot, and have the output go to the contrast.

Can you take a picture of the chipset on the LCD display board? I see Toshiba, but the rest was obscured in the picture.

Edit: It's almost definitely connected to a Hitachi HD44780 or compatible knock-off, but exercising due diligence is prudent.

Extra Edit: An even better idea is that we should research a replacement display. There's probably some swank LED drop-in replacement that will cost you all of $4 and 30 minutes of installation time.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby part12studios » Tue Feb 07, 2017 7:56 pm

ok it was tough but i figured out a good angle to get it without removing it.

Image


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Re: Kawai K1r LCD View angle? Any owners out there?

Postby Rasputin » Tue Feb 07, 2017 7:59 pm

I guess I should have specified better, though. There's a black chip to the left of that sticker, and one on the right. Can you read off what they say? It's almost readable in the picture, but not quite, because of the shadow.

Can you measure the display PCB (in millimeters, preferably)?

I have a feeling you could drop something like this in:

http://www.ebay.com/itm/1602-16x2-HD447 ... SwmtJXT9KG

But I'm not sure exactly how big the stock display is, and how the mounting holes would line up. An additional plus of this is that you would be able to remove the backlight inverter. If you've got any unwanted buzz/hum in your audio then it will take care of a large portion of that.

If you look at the first picture you posted, there is a red/white pair of wires that lead from the display, across the top, and then gets bundled in with a bunch of other wires down the left side, and then exits at a little two-wire brown connector on the mainboard. There should be a transformer somewhere in the area that feeds that with enough voltage to power the backlight. A lot of times those pollute the audio signal quite heavily. New LEDs have a 5V backlight which means you can ditch that annoying transformer.

An added benefit besides getting a newer, brighter, higher contrast display.

Assuming the display uses standard chips, and the display PCB is 80mm x 35mm and the actual display itself (the viewing area) is about 64.5mm x 16mm then you'd be golden.
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Re: Kawai K1r LCD View angle? Any owners out there?

Postby part12studios » Wed Feb 08, 2017 1:02 am

it's 80mm.. i can't really measure inside without removing it which unfortunately looks a bit involved.

but yea i see your point that it shouldn't be a tough thing to work out with a little know how and your advice makes sense!

Thanks,
Caleb
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