Psion 5mx broken cable easily repaired

[cslim]

Hi Everybody,
I have one Psion 5, 2 Psion 5mx with broken screens because of Psion's famous poor screen cable design. I am using my third psion 5 Mx now.
Tonight I took out one of my Psion 5mx and looked at it to see what could be done. All this while I was waiting for a cheap 5mx screen cable to be available.
None appears.
Now after tracing the connections, I am able to repair the broken screen by soldering one wire from the motherboard to the LCD.
Three points to watch :
1. You need to solder the motherboard end first. Easily done on a plated through-hole. Apply glue to the wire.
2. Assemble the Psion back by making sure that the wire and the LCD screen cable are out of the slot of the casing.
3. Unshield the LCD from the metal casing, solder the other end of the wire to the correct point on the LCD large pad. Assemble back the LCD screen and you are done.
There is only one connection in the screen cable which is broken.
So friends, new life for broken Psion 5mx.
When I get some pictures taken I will post them.
Cheers
CS lim

[doogald]

I look forward to the pictures as my 3 month old 5mx just suffered the break.

However, much as I love the 5mx and EPOC, I am seriously considering going to PocketPC once and for all. I switched from CE to EPOC so it will not be new to me but I really need something that I can depend on, and I am not too happy about the 5mx breaking like this after so short a time.

I'm back to using my Mako for now but I'm not all that happy with the usability of the Mako as I am with the 5mx.

[cslim]

Tried taking the pictures but pictures are too big on my camera. That is, no way for you to see thru-hole location or the other bigger pad which you can use to solder the connection.
But it is easy to do - do not need to dis-assemble the Psion all the way.
Let me describe how it is done.
1. Take out Lithium backup and 2 AA batteries.
2. Take out the three screws which hold the back cover of the 5mx. Remove back cover - straight away you can start soldering.
3. Solder flexible thin wire to thru-hole or bigger pad. The thru-hole is near the keyboard connector but of course on the opposite side of the motherboard. You need to carefully scrape off the green covering before soldering it. Once the wire is soldered, apply glue and leave it to dry. On some motherboard the thru-hole is not so strong and can easily drop off.
4. The other bigger pad is near one IC(XK258M) - the IC is the only one with a brown ceramic pad to act as a heat sink. This IC is near to the main CPU, so it is quite far away.
5. Leave wire length around 12 inches.
6. Turn over the Psion and take out the two pins holding the screen and keyboard together.
7. Carefully remove the two small pins on the side of the screen which connects the screen to two springs. Use a small Allen key to drag it out or use a thin blade to push it out through the two slots on the front cover of the screen. Do this carefully. Or go to www.portal-pda.com and take a look.
8. Once screen is loose, slide out the stick on the base of the screen. This stick is the piece which joins to the keyboard.
9. Carefully pull out the metal-covered screen from the plastic cover. Take out back metal cover and expose the row of fingers.
10. Solder the other end of the wire to the finger nearest to the small hole leaving about 1-inch of free wire.
11. Carefully place the screen and keyboard on your table. Use an AC supply or plug in battery and reboot the Psion. Once your screen returns to life, you can take out battery or AC supply and put everything back carefully. Never use force. Remember to put back black and white plastic which covers the fingers.
Send me your address and I will send a postcard to you with the location of thru-hole and pad. I will sketch.
Sorry pictures are blurred.
Cheers,
CS Lim

[cslim]

Forgot one thing - a three-month old Psion should still be under warranty unless you bought it second hand after a year.
cslim

[cslim]

Hi everyone,
Here are the two pictures to repair the one copper track usually broken in Psion 5mx. The pictures show you where you solder one end of the wire. The small pad or the larger pad.
You then tread the other end of the wire thru the same slot just below the small pad and pull it up to the LCD screen.
The other end of the wire goes to the finger which is beside the tiny hole on the screen cable.
When you remove the 4 pins, two on the LCD/keyboard and two on the LCD screen, you see the ribbon cable with a tiny hole in the middle dividing two sets of copper tracks. With the LCD's back facing you, the 11 thicker copper tracks are on your right and the rest of the tiny copper tracks are on your left.
Once you take out the white metal plate, you will see a series of thick copper fingers. Using the tiny hole as a guide, the point to solder the wire is the first finger pad on the left of the tiny hole. If you take a magnifying glass, you would see that it is the first tiny copper track to the left of the hole which is broken.
Note: you repair your LCD screen at your own risk.
I repaired two of my Psion 5MX and have been using for weeks
without any problem. Take out the two tiny pins on the LCD screen with great care.
Good Luck
CS Lim

[cslim]

This is the bigger pad. Both pads are circled and arrowed.

[Zappo]

Don't make the "bypass" cable too long, because opening and closing the Psion wears it down VERY fast if it is too long.

All the above worked great! Thanx!

Only problem is the cable length...
Try to make it as long as the original cable, and you won't have to do it again. (Like myself!)

[Zappo]

my last reply was untrue...

I looked again closely, and noticed the original cable was (is) breaking up further than the first copper track. the second is also gone, and the third is coming up...


Any ideas on how to stop this from happening?
The first time i repaired the cable I guessed this would happen, and i tried to stop it by covering both sides of the crack with tape. this obviously did not work....

[Tony Amos]

Yes.
I tried exactly the same thing with wrapping tape around the cables, but the damn thing has still broken again.
This time even worse, so I guess I will have to bite the bullet and hope that POS will fix it for me. Ouch.:(

[Hendrix]

Hi,

I replaced all 25 ++ conduters with very thin wire (the stuff used in the windings for small motors coated in varnish). I used exactly the opposite philosophy to you Zappo, I made my wires long. The theory being that they flex over the entire length and not at a concentrated point. The wires are fixed using a glue gun. So far as a back up Psion its worked for 3 months, but for how long more? The soldering process took ages, and wrecked my nerves.
I guess the varnish will wear off eventually and short....

I do not know if I would recomend this.

Maybe to stop or slow the fatigue cracks that propogate through the conducters you could use a support stuck to the ribbon, tape or if the cracks are forming from the holes in the ribbon near the screen you could fill the area with glue gun glue. The Psion engineers must have been asleep when they designed this part of the psion 5mx, fatigue cracks and stress points, first year engineering stuff.

Good Luck
Hendrix.

Some nice cheap spare ribbon cables would be the best.

[Zappo]

I'm trying the "Glue theory" right now.

I'm using a "flexible" glue, and when it's dry I'll cover it with some insulation tape.

I'm not gonna try to solder ALL the wires, but I am going to do an extra few, just 2 B sure...

I already apoligized for my first post, because it turned out NOT to be the problem. (the wire length)


Thanx for the fast reply's!

P.s. I agree, Hendrix.
It's some bad engineering by the Psion people.
AND I think it's a disgrace they let people pay that much for a mistake THEY made...
They should almost GIVE the spare cables away...

[Hendrix]

Dont make it too stiff, thats why I had to cut the cable.
I super glued some plastic to the ribbon near the holes about 7mm, I used too much and the screen would not open / close smoothly any more ahhhhh it was a disaster, any I used super glue so there was no going back. If I was doing it again I wouldnt use anything much stiffer then insulation tape, but would probably try supporting just the area where the cracks are and off set the stress by a millimeter..., glue gun maybe in combination with conductive paint .... the possible fixs are endless but the conductors are just sooo small, to do anything perminant with.

Im holding my breath for you...
Hendrix

[Zappo]

Thanx man!

I'm using a "rubbery" glue by the way, so stiffness should be ok...

[Zappo]

Where did you solder those 25 ++ wires to on the "motherboard".

Don't tell me you connected them to where the original cable plugs in...

I wouldn't even think of beginning a nerve wrecking job like that!

did you trace ALL the connections to a place with a bigger "pad" to solder on?

PLEASE tell me you did! PLEASE!!!

[cslim]

HI Zappo,
Yes, I trace the connections when I need to.
I will put up the point for the 2nd connection soon. And even the third if needed.

You can buy SCSI ribbon cable and use them to do the connections. They are tiny and durable. Careful with the plastic covering as it tends to melt back.

What we need is actually for someone to make the ribbon cable connection to the slot and then fan out the connections so that we can solder on the SCSI ribbon cable of our own from that point to the LCD. If made, that cable would look like a tiny fan.
And it will last forever.

CS lim

[Zappo]

Could you x-plain to me how you trace the connections?

Do you use a Multimeter, or just look, or....

I have some SCSI cable lying around (I hoard up a lot of old Stuff), And yes, This would be a pretty good cable to use! (small, thin, strong & flexible)

Thanx for the Tip.

I just don't completely onderstand what you mean by this:

"What we need is actually for someone to make the ribbon cable connection to the slot"

Ribbon cable as in the SCSI cable?
and Slot as in the connector on the mainboard?
If so i did understand!

Idea: The tough end of the original cable (white thingy) could be lifted up to expose the tracks on the end. I've done this with bigger cables. The only problem with THIS cable is that it's so tiny. I guess too small to solder anything on it...
and if it fails, you'll wreck the original cable.

[cslim]

Hi Zappo,
Your idea is what I am trying to say. What we need is someone to make that tiny connector which connects to the slot on the motherboard and then fan out the individual wires so that we can solder the SCSI ribbon cable to it. Then we take the other end of the SCSI ribbon cable with all the tiny wires and solder them to the LCD pcb. That is all. NO need to make the complete cable. That way you save plenty on the tooling cost.

Tracing is done by examing the copper tracks and using a multimeter to confirm the connections.

To prevent the original ribbon cable from cracking further, you use the yellow 3M tape. It is very thin and very strong. Just use two strip to cover the area around the hole.
Soft is life; hardness is death.
You want the original ribbon cable to remain soft, not hard. So do not tape many pieces of thick tape onto it. It breaks too easily when it is hard.

Any takers to make that short cable connector?

CS lim

[Zappo]

Seems impossible to me.
Not by hand anyway

I don't think (IF someone succeeds in doing it by hand) it would be very strong or durable...

Maybe if someone has access to a machine which makes those connectors, it can be done.
But wouldn't this be kinda x-pensive too?

I think tracing as many "unreliable connections" as possible and "backing them up" with the SCSI cable is the best and most realistic solution.

[Hendrix]

You say impossible, I snipped the cable and soldered wires from the screen to the stub of ribbon cable. I say solder but its more of a high bread fix between Solder, melted plastic and glue. As I said before its a nerve killer but do able. Once all was fixed to the ribbon cable I checked for shorts and then covered everything in glue. This has worked for me OK.

Also a possibility is another connector, like the one on the board of the Psion, and then you could use a short piece of cable to link the two together. I guess(hope) the connector has more to Solder too?

I would send pictures but I dare not open the psion. Not that I have low confidence in the workman ship.....

Hendrix

[cslim]

HI Zappo,
here is the 2nd wire connection point:

[Zappo]

I needed that to go on with my repair.

Thanks A LOT!

I repaired the first connection, but after about 2 weeks it failed, because the second connection went too.

If after this repair it fails again, I'm thinking of ordering a new (and enhanced) cable from a germain site...
It will cost me 40 to 50 euro's, but the fix should last...


again,
Thanks a lot cslim!

[Zappo]

If you find (or know) the 3rd and 4th connections, please post them, because I want to back them up too.

The Original cable is (or I hope WAS) cracking, and I want to be sure the Psion will work for a longer period this time.

I'm using a SCSI cable for the repair, and I have used 4 wires (already connected to the screen). When you post any other connection points, I'll solder those too.

Could you explain to me how you go about tracing the connections?

I have a multimeter, but no Idea what "setting" to use, or what to look for...

[cslim]

Hi Zappo,
Full instruction on how to trace is too long - 3/4 pages. Too much to write. So here is the condensed version:
1. Analog multimeter - use highest resistance range to measure continuity. Digital multimeter- use continuity mode.
2. Take out 5mx motherboard(mb) from casing and LCD.
3. Connect LCD to 5mx motherboard. Layout motherboard, keyboard/LCd on your left and CF on your right, CPU should facing you.
4. Locate the point on the LCD white connector which connects to the first wire on the right of the tiny hole(which causes all this cracked ribbon cable). Use magnifying glass and counts the wires from the left end of the connector (This is broken, so you use the wire on the left of the tiny hole as a reference).
5. Wrap one end of your multimeter to a safety needle/pin. Poke this needle your reference point on the wire connector. Tap the other end of the multimeter on the correct LCD finger to confirm that this is the correct point.
6. Once this is confirmed, poke one end of multimeter to this first wire connector point, flip over the mb. Tap all the circular test pads until you find a short.
7. Repeat for the next point and find short on circular pad again.
8. Always confirm that the pad is correct by measuring a short from pad to finger on LCD - that means best done while your ribbon is still OK. Good luck.
CS lim

[Zappo]

Your short version is very clear. Thanx!

I'll have to find the time to do the work, but I'm gonna try it.

I'll try to trace the first two connections first, so I'll know I'm doing it right.

Thanks a bunch!

[Zappo]

I got another 5MX (from a friend) to repair.

Seemed an easy job, because the cable was also cracked (only the first track).

After bypassing the crack, (which went pretty well (had some training)) I tested the Psion...

No change!

So I checked all the connections, and thaught maybe it's a short...

I unsoldered the wire, cleaned in between the 2 connectors (1st big track & 1st small track), and resoldered the wire.

No change!

Then I thaught: maybe, Just maybe some solder came under the cable, and shorts-out there...
So I took a scalpel, and started scratching inbetween the 2 connections, trying to "clean" it.

No change!

So I thought: Maybe a bit deeper?
So I scratched some more...
Until I saw something underneath looking a bit "copper-ish".
Although this troubbled me a bit, I decided to Scratch on, trying to get it "disconnected", and I did.

No change!

Could it be there was a connection between the two connectors? like a resistor, or transistor, or something?

[cslim]

Hi Zappo,
Let's back track a little.
If you open the Psion a little, can you get the screen back on?
If you can, it is certainly a cracked cable.
Then you recheck your connection(S).

If you cannot get the screen back by opening it a little, another check is to test for continuity on the suspected tracks. You must prove that it is the screen cable before repairing it.

Another thing, take care of static electricity too by touching a
safe ground before beginning work.

One last thing, allow for total discharge before putting in the batteries.

CS lim

[Zappo]

I can actually see the crack, but the screen "Flashes" horizontal and vertical when I wiggle the screen... It never goes back on.

I'll check continuity today (no time right now), and see if any other tracks are broken by chance.

Thankz for now..

[Zappo]

I have a digital Multimeter, but NO Continuity mode (unless it's the Diode test mode)...

So I've used the highest resistance range to measure continuity.
The problem is I get readings all over the place! (with a broken, AND working cable)

This is also the reason I gave up tracing the connections on the Motherboard...

any idea what's wrong? (Or what I'm doing wrong?)

[cslim]

Hi Zappo,
On a digital multimeter, you do not want to use the Diode test mode to test for continuity. The voltage applied is too large.

If you get all kinds of readings on the highest resistance range, then you may want to step down to a lower range until you do get 0 to 1 ohm on a short.
Now you know what a short looks like, you can check the rest.

Are you staying near a high power TV station or mobile repeater?
It can cause your digital multimeter to behave erratically.
In that case, you need to do your testing elsewhere or in a shielded area.

CS lim

[Revhead]

If you guys ever perfect this it might be a good idea to put the whole thing together as a guide with pics for future reference. I'm sure that we will all need it at one time or another?