Author Topic: What more i can do?  (Read 36916 times)

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Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #475 on: December 18, 2024, 07:51:00 am »

just check with hands? Whats a little in out things, i do not understand, i saw the picture BUT still unclear.

I suppose that the reason may be in the weakened contacts of the DIP-circuit bushings under IC16.

I would advise you to take any DIP chip, bend one leg and try the clamping force of the contacts one by one.
If all the contacts are tight, spray them with contact cleaner and go around in a circle with this chip making an in-out.

It would be better to change the entire IC panel, but only do this if my guess is confirmed.
I check Pins one by one and use a small needle to open contacts. BUT it is still same.
I double confirm it with multimeter and the clamps are seems connected and shorted..
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #476 on: December 18, 2024, 07:53:16 am »
Hi,

@222Lab_Test222


Could you please read the inscriptions (if any) on the uPD4990 on the working PCB(s) indicating the batch number and year of manufacture and compare them with the inscriptions on the IC23 chips on all the non-working PCBs.

I suspect that this is a "2000Year" problem.

If you are confident in yourself, you can move the chip from the working board to the non-working one (or vice versa).
The working IC name is NEC D4990A 9626F7.
The non working IC name is NEC D4990A 9344F7. The non working one is the new one I just changed recently.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #477 on: December 18, 2024, 07:56:19 am »
Did it (EPROMS DATAs) says or shows anything regarding where the issues are?  :scared:

No.

Do the swap and new scoping and do them exactly like before.
After the High and Low EROMS swap in Non Working Board.
 

Offline u666sa

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Re: What more i can do?
« Reply #478 on: December 18, 2024, 08:04:31 am »
Quit
Valuable lesson learned. You have to know when to quit.
 

Offline squadchannel

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Re: What more i can do?
« Reply #479 on: December 18, 2024, 09:10:46 am »
Quit
Valuable lesson learned. You have to know when to quit.
Exactly.

with LA(logic analyzer), you might be able to find address pins or data pins that are not working, but that's all you can do with scope.
I don't even know where the uploaded image shows, and few people would go back 20 pages to try to understand it. :palm:

my thought is that the PAL/GAL is damaged, or via/trace is damaged. I could also consider a reset IC and RTC. :-//

if you wanted to run Komatsu machines at all costs, I would replace it with a modern motherboard. since it seems to be just an ISA bus.
COM-Express or ATX, ISA bridge and custom pcbs.
« Last Edit: December 18, 2024, 09:16:13 am by squadchannel »
 

Offline Swake

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Re: What more i can do?
« Reply #480 on: December 18, 2024, 10:36:05 am »
Dear fellow electronics tinkerers, I just now discover this thread and it is fantastic how you very systematically approach this repair. The amount of data and information exchanged is impressive.

Allow me to point to a probable anomaly you might not yet have noticed. Sorry, I'm not 100% certain of this as I have not yet read all messages:

In msg 252 https://www.eevblog.com/forum/repair/what-more-i-can-do/msg5720533/#msg5720533 a screenshot is posted of signal OSC3. The scope is set at 2V per division and the signal is clipping out of the screen meaning it is over 16 Volt ! This does not seem right at all for a 5V TTL based system.
When it fits stop using the hammer
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #481 on: December 18, 2024, 11:04:16 am »
Dear fellow electronics tinkerers, I just now discover this thread and it is fantastic how you very systematically approach this repair. The amount of data and information exchanged is impressive.

Allow me to point to a probable anomaly you might not yet have noticed. Sorry, I'm not 100% certain of this as I have not yet read all messages:

In msg 252 https://www.eevblog.com/forum/repair/what-more-i-can-do/msg5720533/#msg5720533 a screenshot is posted of signal OSC3. The scope is set at 2V per division and the signal is clipping out of the screen meaning it is over 16 Volt ! This does not seem right at all for a 5V TTL based system.
Shall I redo it?
 
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Offline Swake

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Re: What more i can do?
« Reply #482 on: December 18, 2024, 11:12:36 am »
Yes please, this would at least confirm the reading. If you could do it on both a good and bad board to compare that would be very nice too.

If the 16 V is confirmed then we should try finding out if this is an expected voltage and if not expected where it is coming from.

When it fits stop using the hammer
 

Offline asis

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Re: What more i can do?
« Reply #483 on: December 18, 2024, 11:47:38 am »
if you wanted to run Komatsu machines at all costs, I would replace it with a modern motherboard. since it seems to be just an ISA bus.
COM-Express or ATX, ISA bridge and custom pcbs.

This is all good.

But how to transfer SW (GUI) control of all hydraulics from the manual remote control and output to the monitor clear pictures of coordinates and corresponding values, i.e. feedback via RS232,485,422?
(Reply #151 on: November 13, 2024)

We do not yet know what kind of controller is in the power section of the unit.
 

Offline squadchannel

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Re: What more i can do?
« Reply #484 on: December 18, 2024, 11:51:07 am »
In msg 252 https://www.eevblog.com/forum/repair/what-more-i-can-do/msg5720533/#msg5720533 a screenshot is posted of signal OSC3. The scope is set at 2V per division and the signal is clipping out of the screen meaning it is over 16 Volt ! This does not seem right at all for a 5V TTL based system.

scope is 10x, but perhaps the switch on the probe is set to 1x. :bullshit:

But how to transfer SW (GUI) control of all hydraulics from the manual remote control and output to the monitor clear pictures of coordinates and corresponding values, i.e. feedback via RS232,485,422?

system is obviously running in DOS, which I believe is connected to the hydro control board via a connector the left side of CPU.
I don't know what kind of communication bus it is, but if it is just a standardized bus, there is a good chance that it can be migrated.
« Last Edit: December 18, 2024, 11:57:56 am by squadchannel »
 

Offline Swake

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Re: What more i can do?
« Reply #485 on: December 18, 2024, 11:56:24 am »
Developing a new board will not be easy for sure, but I believe it is do-able. Especially because there is a working sample, so everything can be measured and confirmed. The software is old fashioned 8-bit MS-DOS code. That can probably be re-used as is or in an emulator or worst case reverse engineered if it is talking to the hardware address directly, like in the case of parallel ports of that era. Everything UART based is going to be a non-issue.

There might already be some more modern versions of this Komatsu machine that have a more recent controller. They'll ask a lot of bucks to sell you one of course.

@222Lab_Test222 do you have access to a thermal imaging camera to verify the board, it might give an indication in what area to search.
« Last Edit: December 19, 2024, 06:34:31 am by Swake »
When it fits stop using the hammer
 

Offline Swake

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Re: What more i can do?
« Reply #486 on: December 18, 2024, 12:03:12 pm »
Quote
scope is 10x, but perhaps the switch on the probe is set to 1x. :bullshit:

In that case it reads as 1.6V, probably a bit more as it goes out of the screen. That would still not be a very good signal. The signal name OSC3 indicates it has something to do with an oscillator. Have seen a couple crystal oscillators fail recently. The failures were not obvious as in one case there was a signal with a not very good quality and in another case it was off half a megahertz from its specs and the system did not start-up.
« Last Edit: December 18, 2024, 04:31:42 pm by Swake »
When it fits stop using the hammer
 

Offline squadchannel

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Re: What more i can do?
« Reply #487 on: December 18, 2024, 12:11:05 pm »
In that case it reads as 1.6V, probably a bit more as it goes out of the screen.

ah, yes. |O ouch!
 

Offline m k

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Re: What more i can do?
« Reply #488 on: December 18, 2024, 03:18:33 pm »
After the High and Low EROMS swap in Non Working Board.

Measured from where?

What say CPU BS8, BS16, BNE0 and BNE1?
Advance-Aneng-Appa-AVO-Beckman-Danbridge-Data Tech-Fluke-General Radio-H. W. Sullivan-Heathkit-HP-Kaise-Kyoritsu-Leeds & Northrup-Mastech-OR-X-REO-Simpson-Sinclair-Tektronix-Tokyo Rikosha-Topward-Triplett-Tritron-YFE
(plus lesser brands from the work shop of the world)
 
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Offline asis

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Re: What more i can do?
« Reply #489 on: December 19, 2024, 01:13:46 am »
Hi,

Please tell me - what chips are on the FRAM bar (x4).
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #490 on: December 20, 2024, 04:27:00 am »
Hi,

Please tell me - what chips are on the FRAM bar (x4).
MX B190415 29F040C11-70G5C531600 TAIWAN
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #491 on: December 20, 2024, 07:22:01 am »
After the High and Low EROMS swap in Non Working Board.

Measured from where?

What say CPU BS8, BS16, BNE0 and BNE1?
I do not understand can you clarify a bit?
 

Offline m k

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Re: What more i can do?
« Reply #492 on: December 20, 2024, 03:31:57 pm »
BNE should be BE.

You've only measured 8 bits, other ROM is missing.

All data lines rice when power comes on and nothing changes until all of them are dropping down.
If data is FFFF it becomes invalid and generates an exception, that means that program execution jumps to other location.
No jumps are present, exception location is in low RAM, so other side of 16 bit data must be something else than FF.

Your 486 manual p.105/224 has a table 7.4.
There you have how memory is accessed compared to those four mentioned signals, there are also situations when only D15-D8 are used.
Your original data and address scopes for faulty board have first data bytes 0D 0D, if we believe that Harry didn't do any mistakes.
Same data for functioning board is 0D E9, but we know that this can't be right, there must be a jump and 0D as first byte will eat the next byte.
So data order is swapped and E9 is the first byte, so next byte pair is also swapped and so first program code is jump to F800, relative and backwards, jump address is negative, and its byte order is swapped again.

Next we can check the combined ROM image and see that F800 has
F800 FA (CLI)
F801 E4 (IN)
F802 35 (port)(irq controller)
F803 A8 (test)
So completely rational start of a code.
We can also be pretty sure that Harry didn't do any mistakes.

Same page of the manual has also figures 7.3 and 7.4.
There you can see how Intel think the situation should be handled.
Native style is 32 bit memory, there both BS8 and BS16 are high all the time, that is not your case.
So those signals can tell whether your system has a possibility to operate or not.

From table 7.4 you can see that there is a possible situation where only D15-D8 is constantly in use.
So our earlier 0D 0D data situation is totally plausible.
But before you go any further you must verify the situation.
And only after then, if the situation really is that, you start figuring out how your system has generated the addressing of figure 7.4.

Bus Size signals should probably be BS8 up and BS16 down, those are inputs, so you can't be sure just simply measuring their levels.
If BS8 is down from the beginning you can be pretty sure it's a fault, there should be 16 bit ROM data first.
Byte Enable signals are outputs, so if any of them is constantly down you be pretty sure again that it is a fault.
Next page of the manual has more examples how data access can be made.

One more thing, page 108/224 and unaligned transfer, it's not very straight forward what data bus should contain at certain moment.
But it is certain that first functioning pair of bytes can't be 0D 0D.

Normally data bus is empty first.
For 16 bit operation another bus cycle is needed, table 7.3 has them.
So first D15-D0 is read and BE0-3 are all down, then D31-D16 is read and BE0-1 are up.
Advance-Aneng-Appa-AVO-Beckman-Danbridge-Data Tech-Fluke-General Radio-H. W. Sullivan-Heathkit-HP-Kaise-Kyoritsu-Leeds & Northrup-Mastech-OR-X-REO-Simpson-Sinclair-Tektronix-Tokyo Rikosha-Topward-Triplett-Tritron-YFE
(plus lesser brands from the work shop of the world)
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #493 on: December 25, 2024, 12:34:37 am »

What say CPU BS8, BS16, BNE0 and BNE1?
Here are signals for Non-Working Board
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #494 on: December 25, 2024, 12:38:30 am »
Continue Images for Working Board
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #495 on: December 25, 2024, 12:39:26 am »
Next we can check the combined ROM image and see that F800 has
F800 FA (CLI)
F801 E4 (IN)
F802 35 (port)(irq controller)
F803 A8 (test)
So completely rational start of a code.

How we can perform this?
 

Offline Harry_22

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Re: What more i can do?
« Reply #496 on: December 25, 2024, 02:03:40 am »

We can also be pretty sure that Harry didn't do any mistakes.


@222Lab_Test222, when the time permits check our measurements.
Measure directly on the chip pin. Start with non-working board IC16 data.
 

Offline asis

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Re: What more i can do?
« Reply #497 on: December 25, 2024, 03:00:30 am »
Hi,

I need pictures of SIMM72-ROM and SIMM72-Flash modules from both sides.

I also need a better picture of the back side of the PCB.
You're welcome.
 
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Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #498 on: December 25, 2024, 04:18:21 am »
Hi,

I need pictures of SIMM72-ROM and SIMM72-Flash modules from both sides.

I also need a better picture of the back side of the PCB.
You're welcome.
There are various kind and version of those.
I am sending one which is currently working on another board.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #499 on: December 25, 2024, 04:33:06 am »
I did best BUT camera is so bad.
Here is Full Image as well as parts which i click.
 


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