Microvision replacement screen project - pre-order & purchase here

[Turbo-Torch]

Really basic, but a low battery will cause exactly what you're seeing.  I was playing with a bench supply and about 7.5 volts was the threshold.

 

Also, look at the straight brown zebra strip under a magnifying glass.  The side that was in contact with the solder pads will have little indentations from being compressed for over 40 years.  Be sure to put it back the same way.

The stepped zebra can only go back one way.

 

Edit...

Are you using the green foam pad off the old screen?

Edited March 5, 2021 by Turbo-Torch

[nickle241]

7 minutes ago, Turbo-Torch said:

Really basic, but a low battery will cause exactly what you're seeing.  I was playing with a bench supply and about 7.5 volts was the threshold.

 

Also, look at the straight brown zebra strip under a magnifying glass.  The side that was in contact with the solder pads will have little indentations from being compressed for over 40 years.  Be sure to put it back the same way.

The stepped zebra can only go back one way.

 

Edit...

Are you using the green foam pad off the old screen?

i didnt realize it didnt have any low voltage cutoff, then again i really should have since it predates such designs and its already well known for lacking several rather important self protection features, the fact that i have to be so careful of the cartridge connection as well as taking care not to start a fire in the battery compartment should have clued me into that

[thegoodwillgamer]

Got the screens in the mail today!  

Swapped it out in just a couple minutes and we're up and running!  Thanks a ton @5-11under I can finally play my Microvision for the first time since I bought it 8 years ago!

 

[livingonwheels]

I've checked through that Facebook group, and I do see some users with similar issues but no real solutions. I cleaned both zebra connectors, no luck there. They look nearly brand new though. Brought the zebra connectors closer to the screen, issue remains the same. Cleaned all contacts in the Microvision with Deoxit. Checked all traces with a multimeter, they are all fine. Changed the battery to a brand new one, no change. I noticed those indentations on the zebra strip and installed it the same way, and yes, I am using the green foam pad. I'm about 4 hours into this, with no change. I wonder if whoever opened this years ago caused static electricity in the unit and blew something out. I'm out of options here. I'm almost to the point of giving up and letting someone else here have a try.

Edited March 6, 2021 by livingonwheels

[nickle241]

2 hours ago, livingonwheels said:

I've checked through that Facebook group, and I do see some users with similar issues but no real solutions. I cleaned both zebra connectors, no luck there. They look nearly brand new though. Brought the zebra connectors closer to the screen, issue remains the same. Cleaned all contacts in the Microvision with Deoxit. Checked all traces with a multimeter, they are all fine. Changed the battery to a brand new one, no change. I noticed those indentations on the zebra strip and installed it the same way, and yes, I am using the green foam pad. I'm about 4 hours into this, with no change. I wonder if whoever opened this years ago caused static electricity in the unit and blew something out. I'm out of options here. I'm almost to the point of giving up and letting someone else here have a try.

mine did give me an hour or so of various screen issues before it finally decided to work so i did run into some of the screen faults but yours is doing something that seems highly atypical for a screen connection issue from what ive seen so far from mine and others, those horizontal bars on the screen seem like they are probably a symptom of a bigger failure, your full contrast pic made it clear enough that all the points were connecting to the screen and it appears to be sending data to the screen controller normally since its mostly functional which unfortunately leaves only a possible failure within the screen controller itself.  this is somewhat problematic since from what ive read that is a custom chip and since its the only important component in the console itself this leaves repair options rather limited.   

i could be wrong about this since these decades of being unserviceable have left a very sparse amount of info on their faults and causes but from what little i can put together it does seem to be a damaged 'graphics' chip, its still somewhat functional but chips of that era were prone to only suffering partial failure for a number of reasons

[Deteacher]

While I patiently wait for my screen to arrive, I have a question about the potentiometer.  I have no idea if it's good or bad, yet, but let's assume that it is.  Would a potentiometer from an Atari 2600 paddle work in it's place?  Are they one and the same?  Sorry if this is a noob question.  

[BigO]

7 hours ago, Deteacher said:

While I patiently wait for my screen to arrive, I have a question about the potentiometer.  I have no idea if it's good or bad, yet, but let's assume that it is.  Would a potentiometer from an Atari 2600 paddle work in it's place?  Are they one and the same?  Sorry if this is a noob question.  

No, the one in the Atari paddle is 1,000,000 ohms The one in the Microvision is 10,000 ohms. 

Okay, technically it would electrically function and wouldn't hurt anything. But for every degree of rotation you would get 1000 times the movement that you would get with the original. It would be unplayable.

 

The pot in the Microvision is probably okay, or salvageable by cleaning. I use Deoxit that is made for cleaning and lubricating potentiometers.

Edited March 6, 2021 by BigO

[BigO]

Got mine swapped out today. Nice, crisp and clean display. Functions perfectly.

[PaperJam]

While I patiently wait for my screen to arrive... I visit here 10,000 times a day to watch everybody else enjoy repairing their systems.

 

I still have my original Microvision with 6 games.  It’s been 40 years since I last enjoyed playing.  Leaving it in the attic with my other childhood memories destroyed the LCD.  I wonder if I will be as good at Block Buster as I remember.

 

 

[ArcadeJunkie]

Other than the screen issue, the microvision was also notoriously sensitive to static electricity.  I highly recommend that anyone performing work on a unit takes the necessary steps to protect them from static discharge.

[adventurevision]

Thanks again 5-11under!

 

Two units back in action. Only took about 20-25 minutes total to do both. I did have one unit need to be taken apart a second time and the smaller screen connector wiped down and slightly repositioned.

 

Such great looking screens. Again, thanks 5-11under!

[+5-11under]

FYI, I've caught up on the last few days (or so?) worth of orders, and mailed them out today.

 

The online store at https://videogamepcbs.com/products/20-MV-LCD.html shows about 15 units remaining. I do have about 15 more held back, in case of issues, and for personal use. I'll keep those held back for probably at least a month, to ensure everyone who's bought one properly receives it. That might be it, unless there's a convincing reason to order another batch.

 

Thanks to all who have bought these so far. It's definitely appreciated!

I think I've nearly broken even on the project (so far - the rest is the gravy or insurance), which is kind of nice, given that that was the ultimate goal for this project.

[Deteacher]

I received mine today and wasted no time into getting the screen replaced.

 

However, I've taken this thing apart 3 times, paying close attention to the instructions.  Each time I put it back together, I get no display at all.  I've played with the alignment of the zebra connections and I've fiddled with the contrast, but I get nothing at all.  I know the system is working because I get audio.  I was even able to verify the paddle works because I launched a ball in Block Buster and I got the ball to keep bouncing up and down.  Once I moved the paddle, I heard the "ball lost" sound.  All the buttons appear to work as well (at least from what I can tell, so far.)

 

I'm going to give it another try in the morning.  I'll clean the zebra connectors with IPA and make sure everything else gets a good cleaning.  In the meantime, if anyone has any suggestions, I'm all ears.

[nickle241]

is it possible the screen controller is dead?  its not like the system is reliant on it to run since power and controls are all handled by other components and the processor is in the cartridge, the processor being a separate component seems to give it a ton of leeway in terms of what it will put up with so it wouldn't surprise me if it could also keep going uninterrupted with a dead gpu

[Deteacher]

5 minutes ago, nickle241 said:

is it possible the screen controller is dead?  its not like the system is reliant on it to run since power and controls are all handled by other components and the processor is in the cartridge, the processor being a separate component seems to give it a ton of leeway in terms of what it will put up with so it wouldn't surprise me if it could also keep going uninterrupted with a dead gpu

I suppose that's possible.  Hoping that's not the case.  I'll give it another go tomorrow when I have lots of daylight to work with.

[Deteacher]

Ok, so I spent all morning on this unit and I still have no display at all.  I'm starting to think the graphics controller might be bad, but I don't know where the graphics controller is, or how to troubleshoot it.  If I could get even on row (Hell, even 1 pixel) to light up, I'd be happy that I was making progress, but I get nothing but a blank screen. 

 

Here's what I did this morning:

 

 - Took it completely apart again and cleaned everything with isopropyl alcohol.

 - Cleaned all the contact pins with an eraser, followed by more IPA.

 - Checked every pin for continuity with my multimeter.  All traces are making a connection.

 - Took the potentiometer completely apart and cleaned all the old grease out, and sprayed with DeoxIt (just for good measure.)

 - Used a brand new 9V battery.

 - Played with the contrast all the way down and all the way up.

 

The unit is still behaving the same way.  Audio works.  Buttons work.  As far as I can tell, the paddle is good too.

 

If someone can point me in the right direction on how to troubleshoot the graphics controller, I'd appreciate it.  Otherwise, it looks like this unit will become an organ donor and I'll be heading out to Ebay to look for another unit.

Edited March 9, 2021 by Deteacher

[nickle241]

the graphics controller is the only chip in the console itself, i believe its a custom chip, but you should still be able to check its outputs

[Deteacher]

Just now, nickle241 said:

the graphics controller is the only chip in the console itself, i believe its a custom chip, but you should still be able to check its outputs

Oh...that big long black chip?  Ok, I can test that out. I'll report back what I find.

[nickle241]

http://www.atarihq.com/danb/Microvision.shtml#chippinouts

this link has the pinouts for the chips so you can check against it

[Deteacher]

Ok, I checked every trace on the board for R0-R15 and C0-C15 to the chip and there's continuity on each line.  So, the only thing I can deduce now is I'm simply not lining up the zebra connectors properly.  But I would think I'd be getting, at the very least, garbled graphics, like livingonwheels was getting.

 

One pixel...my kingdom for one pixel! 

[nickle241]

is it actually putting out a signal on the row and column pins? though i guess most people wont have the tools to check that, i certainly dont, but if you do a voltage check between two pins you know for sure are supposed to be connecting such as somewhere in the starting wall on block buster you might picks up bursts of activity with a standard multimeter

edit: any column should work but im not sure which direction the rows count from so that would need some trial and error

Edited March 9, 2021 by nickle241

[nickle241]

if the chip checks out fine then you could try replacing row zebra strip, i found an ebay seller supplying a ton of different dimensions for standard zebra strips, the stepped one you will just have to hope is fine since its so unusual

[BigO]

3 hours ago, Deteacher said:

Ok, I checked every trace on the board for R0-R15 and C0-C15 to the chip and there's continuity on each line.  So, the only thing I can deduce now is I'm simply not lining up the zebra connectors properly.  But I would think I'd be getting, at the very least, garbled graphics, like livingonwheels was getting.

 

One pixel...my kingdom for one pixel! 

A really dumb, far-fetched, out-of-left-field question: did they assemble the LCD backwards, with the reflective surface stuck on what should be the front? If that were the case, I believe the symmetry of the display would allow it to be physically installed. It's pretty hard to see those transparent conductive traces, but held in the light a certain way and watching the parallax as you move the display does let you see which side they're on (at least on one of the OEM displays that I de-installed and other bare glass LCD's I've tinkered with).

However, if 5-11 tested every unit, then this unlikely scenario would be rendered un-possible.

[nickle241]

3 minutes ago, BigO said:

A really dumb, far-fetched, out-of-left-field question: did they assemble the LCD backwards, with the reflective surface stuck on what should be the front? If that were the case, I believe the symmetry of the display would allow it to be physically installed. It's pretty hard to see those transparent conductive traces, but held in the light a certain way and watching the parallax as you move the display does let you see which side they're on (at least on one of the OEM displays that I de-installed and other bare glass LCD's I've tinkered with).

However, if 5-11 tested every unit, then this unlikely scenario would be rendered un-possible.

it actually wouldnt matter from what i can tell, the screen is just a matrix and both edges are the same with the traces on the 'inner' layer, it would take one hell of a manufacturing screw up for the screen to be outright defective in that way, my old one leaked in such a way it made it easier to see the internal traces and there is nothing complex about it that would care if it were reversed

[BigO]

On 3/9/2021 at 2:41 PM, nickle241 said:

it actually wouldnt matter from what i can tell, the screen is just a matrix and both edges are the same with the traces on the 'inner' layer, it would take one hell of a manufacturing screw up for the screen to be outright defective in that way, my old one leaked in such a way it made it easier to see the internal traces and there is nothing complex about it that would care if it were reversed

That isn't what I meant.

 

I know it's a matrix. I'm talking about which face of the glass the zebra strip is contacting, not the polarity of the connection. I should have used the term face instead of side, I suppose. 

 

(As a matter of trivia, according to my research, the polarity of the connection is reversed frequently under normal operating conditions to prevent damage to the display. There's a specific pattern/timing fed from the processor to the controller that causes the controller to reverse the polarity of the signals.)

 

If the reflective material were attached to the wrong surface, then the conductive traces would be on the top faces of the pads instead of the bottom side when the LCD is installed with the reflective surface down. I think the symmetry would let that happen. I don't have one of the LCD's in front of me at the moment.

 

Again, it's a very unlikely scenario. But, it's not expensive to check.

Edited March 15, 2021 by BigO