• Please review our updated Terms and Rules here

WOOHOO!!! Got my 2810HD!!

L

leeb

Veteran Member
Joined
Jan 21, 2009
Messages
709
Location
Palm Springs CA
I have wanted another 2810 since I was forced to sell mine years ago...
:eek:nfire:AND I got it TODAY off ebay... WHOOHOO!!!:eek:nfire:

Not 100% sure its working as the guy said it doesnt come up for long... likely low/dead battery, (and bad P/S),

but I have worked with variations of them alot... recently.

I CANNOT WAIT for it to arrive! :eek:nfire:
 
Okay, not so WOOHOO...

Okay, not so WOOHOO...

It seems like, no matter how much I spend, I always end up with junk!
Well, not always, but, as I put in the 1500 blog...
The value of an ebay item is INVERSELY proportional to the amount spent on said item.

The 2810 has a power-up problem... meaning it WONT.

Specifically, it ATTEMPTS to but immediately (actually a varying time but QUITE short) shuts down again. SOMETIMES the ON/SPEED LED will toggle from ON (green) to SLOW (yellow) before it dies.

What bothers me the most (as the power problem was stated in the description) was that SOMEBODY had been monkeying with it before, OPENED the hard drive and LOST THE RUBBER GASKET!!!
Then they had the.... nerve... or whatever to use EPOXY or SHOE GOO or SOMETHING to attempt to seal the top of the drive... and failed miserably! It wasnt even solid... or hadnt enuf time to cure...

Anyway, I commented about this to the seller and got an acceptable part of my payment back. So everybody's happy.

WRONG!!!

I very much wanted this unit to become useable QUICKLY. IT is (like) the first portable computer I ever bought... While mine was eventually 'tricked out' with the modem and 5Mb of 35-pin(!) memory, I have always wanted another one to replace it. I really hoped that this one would arrive with a 287 and a modem in it... tho I 'knew' better.

So... I must be patient. I must build myself a logic probe and see if I can determine what is at fault. I can only hope it does not come down to the 80c51 being used as the Power Management Controller (PMC... or PMS!) as I have NO idea how to program another one to replace it!!!

I paid for and got the PDF file schematics for the 2810, and intend to follow this one through (although the 1800 SEEMS to be the easier to 'fix'). One nice thing about the PDF... I NOW KNOW THE PINOUT of the 'unique' 35-pin memory!!! Once I find a(some) chip(s) I can use to make boards with, I will attempt to make SIMMS for this machine... AND one for the 1500, which APPEARS to use the same SIMMS!
(There may be a potential market in the 'dinosaur' division here!)

This means that, for now at least, the 1500 that I paid $10 for is the only one that works completely...

Thus is proved the equation: V(ei) = v(ei) / C(ei) . Where V = ACTUAL VALUE, ei is Ebay Item, v = perceived value, and C = Cost.

(amidoingitrite? SOOO bad at algebra :p)
 
Last edited:
I have done some more poking around and found out that there MAY be a charging problem with the 2810... which may be related to the power-up issue... and maybe not.
Specifically, It shows NO attempt to produce voltage (of any significance) at the battery-charge terminals when 'tricked' into believing a battery is there. Or so I think... the behavior of 2810 SEEMS similar to the 1800 in design.

MORE interestingly, when there is NO battery at all, the LOWBAT light (red) BLINKS... and that is the 1st time (I know of) that Ive seen that.

Now that the 'weekend' is showing up I may learn more!
 
We learn by doing...

We learn by doing...

(This is where this REALLY belongs!)

Yesterday I have learned some things regarding the 2810 problem...
I tracked down a section that is a DC-DC inverter... it takes the 16v source and creates a -22v and +5v supply from it, on command from the 'on button'.

But the 5v was not showing up... unlike on the 1800...

SO...

I pulled the inverter off the 2810 (a tedious chore until the CHIPQUIK showed up!) and replaced it with the inverter from the 1800.

Unfortunately the 5v STILL isnt there.
This means, I suspect, that SOMETHING 'further down the line' is causing the 5v to 'disappear'... either the voltage is not being recoginzed by the circuit that confirms it is there and shuts it down before my multimeter can register it, OR...
It is being shorted, thus causing the previous condition.
NOW, I do seem to hear something from the inverter that I didnt remember hearing before, but I wont be able to confirm anything until the original inverter is placed into the 1800...
Which will require some 'creative wiring'. The leads (which were designed to come off anyway) were... shall we say, sacrificed... on the first attempt.

Thus the title. :D

** Today is yard work. There will be VERY LITTLE done on this issue till tomorrow.
 
It has finally happened....

It has finally happened....

I am getting tired of fighting this 2810.
So Im gonna focus on the 1800 for awhile.

For a SHORT TIME last nite, it STAYED ON tho the 22v did not work.
It SEEMED that the CPU was running and resetting, but I couldnt get it over to the LCD montitor to see if the external video was working.

Im tired... tired of playing the game....aint it a cying shame... Im so tired!
:D
 
Sometimes you just need to 'walk away' from it. (I think most of us have been there.)

Take a couple days break and a new idea about how to tackle the problem may crop up :)

Good luck!
 
Yup, a refresher on the project like sleep on it and see if you end up with a nice "why didn't I think of this the first time?" trick to try. Also nice of you to post the progress and troubleshooting for others to read over. I'm sure a few folks here might have some ideas to try also. Does it have any removable devices you can disconnect? (i.e remove any cards and drives and reduce the scope of the problem).
 
Vint said:
Sometimes you just need to 'walk away' from it. (I think most of us have been there.)

Take a couple days break and a new idea about how to tackle the problem may crop up :)

Good luck!
Click to expand...

Thanks ALOT! I know Im documenting this for 'posterity' but input IS nice! I WONT talk about the sunburn I got yesterday cleaning out the pool!

barythrin said:
Yup, a refresher on the project like sleep on it and see if you end up with a nice "why didn't I think of this the first time?" trick to try. Also nice of you to post the progress and troubleshooting for others to read over. I'm sure a few folks here might have some ideas to try also. Does it have any removable devices you can disconnect? (i.e remove any cards and drives and reduce the scope of the problem).
Click to expand...

At this point it is down to the power supply and the system board. I just need to 'back away' from it and work on the 1800 and finish the boards for the 1500 and 2810. That will keep me busy for awhile, Im sure! 8-)
 
Some musings...

Ive noticed that the 2810 seems to 'try harder' when a battery is attached... It will cycle up UNTIL the display (backlight) comes on. Without the battery, it will practically 'blink' and go out...

The 1800 isnt much better. The DC-DC converter SEEMS to be fine, and outputs the 5v and 22v but it still will not come up.
I BELIEVE it is due to the peripheral IC being gone (the 82c711) that it 'freaks out'... or so I hope!
I have to get a better workbench... I tried to solder a hole thru the carpet yesterday. :shock:

The next step is to clean the POUND of solder off the removed 82c711 and try to reassemble it... broken pad and all!
(I have created a new trace for it... the 'direct solder' approach should suffice to compensate for the missing pad.)

Thus, it continues! :D
 
A partial VICTORY!!!

A partial VICTORY!!!

Despite all odds, I
WAS ABLE TO RECOVER THE 2810's HARD DRIVE!!! :eek:nfire:
I NEVER expected it to clean up and BE ERROR-FREE!! :eek:nfire:
(At least it is right now!)

In case you didnt know, some previous SOB lost the cover seal and used 'Shoe-Goo' or somesuch to attempt to replace it.
IOW, a sticky, unreadable MESS! :mad:

But, it seems some alcohol pads and a lint-free cloth were able to clean it!! :eek:nfire:

Almost makes up for the lack of progress on fixing the gawd-dern computer! :D

Edit:
Later I learned that the 2nd drive (from the 1800) does NOT have a bad head as I believed, but simply has ALOT of bad media errors. I doubt recovery of this drive is possible, but I will keep trying!
'When ya got nothin' ya got nothin' ta looz!' :mrgreen:

Edit2:
I have tracked down another drive that had its board fried... assuming the media is good as reported I can use the board off this 2nd one to fhx the 4th one... this is getting confuzzin' :huh:
 
Last edited:
I am becoming more & more convinced the issue lies in the charging/charge recoginition circuit(s)...
As I said, if I have a battery on it there is a noticable increase in the time between power-up start and power-down... which either coincides with the startup of the PS supply voltage to the LCD (not IN the LCD as it happens on BOTH VGA panels), or is CAUSED by the PS voltage AND/OR 22v supply driving the LCD itself...

I MIGHT attempt to get the 16.5/17v PS voltage sent to the LCD to replace the 22v and see if it attempts to work 'a bit better/longer'.

I am still interested in the apparent error in the charge circuit... the battery SENSE line on the 1800 (a 'behaviorally similar' system) shows a full 5v but the 2810 (with the capacitor changed) shows only 'about 3'v. Also, when the SENSE line is connected to its return, the 1800 pushes the battery connectors up to PS voltage (16.5/17) for a short time... expecting the voltage to be lower from a low battery, I presume...

I am willing to speculate that I have one (or more) transistor 'switches' failing in the charge circuit and it is 'backwashing' into the power control...

But a nap is long overdue and I HATE to miss them! :roll:
 
Well, I have my el-cheapo logic probe made... and Im ready to delve into the netherworld of the power management system.

But I fear the 1800 may be lost... the DC-DC converter does NOT generate the 22v and it seems that the board will not come up properly without it... altho I thought it tried before the install.
I have checked-&-rechecked and cannot find anyplace where solder-bridges might exist. Nonetheless, it doe not boot but does sometimes complain about video issues (bwo BIOS beeps).

I wish the 1800 would work... I guess I should not have removed the 711 until this part was checked. MOST of the power-up logic works... I need to determine if the lack of 22v IS IN FACT the cause of the problem.

Which is tough since I have schematics ONLY for the 2810. Ugh.
 
AT LAST!!! SOME progress!

AT LAST!!! SOME progress!

Today I actually made some progress on the power issue.
Because the DC-DC converter is responsible for engaging the main 5v for the system I focused on and was able to force the MAIN 5v supply active, which powered MOST of the system...

The system beeped 4 times (sometimes instead it will beep 5),
accessed the FD,
accessed the HD,
and beeped twice more.

This tells me that the processor is running, accessing ROM, the FDC controller and the HD controller. Since the power for the backlight and/or the 22v for the LCD panel dont seem to be active, information on the screen is unreadable (if there at all)...
It did NOT seem to boot the hard drive, which I know has a working system on it and is the original 20mb drive from this system.
I cannot tell if that is due to my inability to 'press F1 to continue' or not as no keyboard control seems to exist. (The CAPS/NUMLOCK/etc DID cycle upon power-up as it should, but at no time was I able to enable/disable the CAPS or NUMlock lights.
Will try a keyboard substitution and edit later.

Edit: Well, the other keyboard(s) apparently have a wider connector... and cannot be used. The only key(s) I was able to operate were
the <func><keypad> combo. That turns on/off the KEYPAD light. Even relocating the CAPS key (an option on these machines) did not work to operate the CAPS light.

Either way, important progress has been made today. I feel good about the results! :mrgreen:

2nd Edit: I did not think about the external keyboard connection. Gonna try that next!

3rd Edit: External keyboard did not respond either, but it is fairly new and may not be completely compatible...

4th Edit: Was actually able to get it to stay up on its own by pressing the power button after it did the last beeping, and multiple times it stayed that way until I pressed a key. Not all of them caused it to drop power, but it SHOULD be interrupt-driven... Still havent seen the backlight come on which is not dependent upon the DC-DC converter...

As I said, pleased with the overall results so far!
 
Last edited:
I cant believe I did the whole thing!!

I cant believe I did the whole thing!!

There has been a panasonic cf-270 laptop on ebay for awhile that has been asking nearly a thousand bucks for a machine that is claimed to be 'dead'...
(This machine is their equivalent to my Tandy 2810... they made it, in fact.)

For some insane reason (too much mocha latte, perhaps), I made the mistake of offering $50 for it.
They accepted.
I paid for it.

I will hope it's issues are simple... blown fuses, bad power supply.
IF NOTHING ELSE, I have a system-board-compatible parts machine that I MIGHT be able to use as a soundboard to repair the 2810 with... I MIGHT need to use the keyboard 80c51 to attempt to make a new one for the 2810... based upon what has been discovered recently.

Of course, I may need to not eat next week. :roll:
 
Last edited:
I must spend some more time analying the schematics

I must spend some more time analying the schematics

There is ALOT of power-up going on in this beast... and I will need to go thru the schematics and attempt to learn which latch(es) go active and so forth...
The machine still starts up the backlight (albiet briefly) when the power button is pressed, as before, so there is apparently no fault there... unless the 'switch(es)' are not working properly...

So, I will peruse the mass of Qxxes, ICxxes and black traces to see if I can reason-out the logic error.

At least until the CF-270 shows up and I can try a different keyboard/80c51 controller combo...

I THINK that, if the keyboard were operating correctly, I could get a system up and toggle to the external video... at which point I would be able to run the internal ROM-based diags (IF they werent dumped by TANDY) like the CF-270 has... after all, they ARE the same machine!

And, of course, I need 'about a dozen' CMOS batteries (of 2 different types, natch!) for all these things!

But first, I have a PET scan to go thru... joy.
:D
 
Last edited:
Hit the snooze button again, plz!

Hit the snooze button again, plz!

With the pending arrival of the panasonic CF270 (mechanical equivalent of the 2810) I have been 'taking a nap' in wait for the sibling...
And experiencing a bit of anticipation... waiting to see how badly it is 'broken', as advertised...


But if there is ANYTHING missing internally, there will be h-e-ll to pay!

I'm certainly developing a collection of Tandy laptops... and all but one is broken! :wow:

Hopefully, 'tis a temporary condition! :D
 
How did you make the el-cheapo logic probe? A two color led, a resistor and a pen-case? I'm having logical problems with my KVM and want to see what's on it's crazy mind.
 
Exactly so! Just be aware that since it is not self-powered it WILL affect the circuit being tested... but that is how I found I could get the main power to come on, so Im not complaining!

I wired polarity so that green was positive, red was negative... AC will show as yellow...
 
The panasonic CF270 arrived today... and I learned something interesting...
Actually a couple of things.

I prefer the Tandy-dark case over the Panasonic-light case.
The Tandy has square LEDs and the Panasonic has small round ones.

and...

It has the EXACT SAME PROBLEM the Tandy does... partial power-up and all! :eh:
Of course, the hard drive was also defective... but its controller board was 'hokey'...
The 'spare' I had was able to fix it and.... IT HAS DATA!!! In fact, there are CF-270 specific files that I am likely NEVER to find anywhere!!!
:D :D Happy Happy! Joy, joy! Happy, happy joy! :D :D

Unfortunately I cannot swap parts and make the systems work that way.
... and it looks like the Tandy keyboard is defective... and I dont know if it can be fixed... bummer.

So I have to figger out what's wrong so both of them can work!
 
Last edited:
I now have another 1800hd on the way (well, Monday...), compliments of Ebay...

I HOPE beyond all hope that it has only the minor HD issue... as opposed to the battery-damage the other got...
I am not yet '3m' competent so SMD work will likely be learned on the 'original' 1800...

As Ive said other places, the 1800 can use 'normal' 3-chip 30-pin memories (2 in fact) so I have enuf right now for 2 machines...
IF the new arrival works, I can feel more comfortable about 'guinea-pigging' the first one :shock:

Repair of the 2810 (and cf270) is currently a mental exercise... and it IS a headache! The big problem is keeping the board vertical to probe while it is 'forced on'...
On the bright side, the battery on the cf270 holds a 'respectable' charge... meaning it doesnt die out in 5 minutes... so it can be used for off-the-wall testing..


Edit:
My 'weekend' is fast approaching... I believe I am going to spend part of it making DOS6.22 backup 'mirrors' of these drives with original (and not-so-original) software... that way I dont have to feel panic if I 'trash' one of them! (since the 2810's drive IE the 'shoe-goo' one has been affected by 'residual' goo yesterday...) :D
 
Last edited:
You must log in or register to reply here.
Back
Top