Author Topic: What more i can do?  (Read 36939 times)

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Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #375 on: December 04, 2024, 12:24:09 am »
Hello, you can try to check (&click) all of the dip switches, it looks like BIOS is not well configured or so. Click them ~20 times for each position and check that they are in right position compared with the working board.

Check (replace) condensers, power lines, clean connections (memory), check voltage amplitudes on IC's main legs,
 
All the deep switches are according to the working board, I also tried numerous time to change the deep switches with other BUT it doesnt beep if those deep switches are wrongly configured.

 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #376 on: December 04, 2024, 04:40:59 am »
Working Board Address Inputs Wa0-Wa9
« Last Edit: December 04, 2024, 04:44:36 am by 222Lab_Test222 »
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #377 on: December 04, 2024, 04:41:59 am »
Continued
Working Board Address Inputs Wa10-Wa17
« Last Edit: December 04, 2024, 04:44:51 am by 222Lab_Test222 »
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #378 on: December 04, 2024, 04:44:19 am »
Working Board Data Outputs Whqo-Whq7 (Working board High BIOS pins)
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #379 on: December 04, 2024, 04:45:44 am »
Working Board Data Outputs Wlqo-Wlq7 (Working board LOW BIOS pins)
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #380 on: December 04, 2024, 04:47:21 am »
Non Working Board Address Inputs A0-A9
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #381 on: December 04, 2024, 04:48:18 am »
Continued...
Non Working Board Address Inputs A10-A17
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #382 on: December 04, 2024, 04:50:45 am »
Non Working Board Data Outputs Hqo-Hq7 (Working board High BIOS pins) and
Non Working Board Data Outputs Lqo-Lq7 (Working board LOW BIOS pins)
These are same, not a single change, I guess there is no address inputs so these  data inputs are same and dummy outputs..
 

Offline asis

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Re: What more i can do?
« Reply #383 on: December 04, 2024, 11:43:25 am »
Hi,

@222Lab_Test222

I admire your persistence.
I try to help as much as I can, as do many others.

But, I doubt that anyone will be able to generalize the data that you presented.
-
Although, "The ways of the Lord are inscrutable"
Waiting for the DAMP
 

Online drhex

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Re: What more i can do?
« Reply #384 on: December 04, 2024, 09:48:40 pm »
Looks like all address signals are there? Didn't you say the high bits were missing on the EPROM? If they exist at the CPU and not at the EPROM this may well be your issue.
How many of these defect boards do you have? Maybe send a few around for people to have a direct poke?
« Last Edit: December 04, 2024, 09:51:16 pm by drhex »
 

Offline Harry_22

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Re: What more i can do?
« Reply #385 on: December 04, 2024, 10:14:10 pm »
Here are the Address and Data pictures of the first 20us for the working machine.
The first address is 3FFF8h.
The comparison for non-working machine I will make next.
« Last Edit: December 05, 2024, 02:37:02 pm by Harry_22 »
 
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Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #386 on: December 04, 2024, 11:12:12 pm »
Looks like all address signals are there? Didn't you say the high bits were missing on the EPROM? If they exist at the CPU and not at the EPROM this may well be your issue.
How many of these defect boards do you have? Maybe send a few around for people to have a direct poke?

To be honest, I think the address signals of the non working board is just dummy signals. Why?
because it keeps changing and is not constant. Also the GREEN LED makes the signals different, Either it glow or Not, it also affect the signals in non working board.

Now I have around 5 of them, I already  solved other 3 of them with same issue.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #387 on: December 04, 2024, 11:14:27 pm »
I admire your persistence.
I try to help as much as I can, as do many others.

But, I doubt that anyone will be able to generalize the data that you presented.

Is there any others things and checking you want me to do?
Any ideas or things is ok for me to check and inspect.
 

Offline Harry_22

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Re: What more i can do?
« Reply #388 on: December 05, 2024, 07:05:02 am »
How much boards have you already repaired?
Just for statistic.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #389 on: December 05, 2024, 11:47:31 am »
How much boards have you already repaired?
Just for statistic.
I repaired 3, now i have 5 left of all same issues.
 

Offline Harry_22

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Re: What more i can do?
« Reply #390 on: December 05, 2024, 12:01:42 pm »
And what the issue was with repaired 3 ones?
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #391 on: December 05, 2024, 12:58:40 pm »
Check Post reply #364
 
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Offline Harry_22

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Re: What more i can do?
« Reply #392 on: December 05, 2024, 09:35:55 pm »
Finished with address buses.
The point in A4, A3 is clearly visible where the difference begins.
 
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Offline asis

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Re: What more i can do?
« Reply #393 on: December 06, 2024, 12:45:11 am »
Hi,

@222Lab_Test222
Glad you got it all working out.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #394 on: December 06, 2024, 01:01:57 am »
Those were simple ones, tough ones are still left
 

Offline asis

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Re: What more i can do?
« Reply #395 on: December 06, 2024, 02:04:02 am »
You definitely need additional equipment.
At least:
a programmer  Labtool 48 XP/UXP.
UV irradiator for erasing microcircuits.
DSLogic 16 logic analyzer.
-
One scope is clearly not enough.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #396 on: December 06, 2024, 02:36:02 am »
You definitely need additional equipment.
At least:
a programmer  Labtool 48 XP/UXP.
UV irradiator for erasing microcircuits.
DSLogic 16 logic analyzer.
-
One scope is clearly not enough.

Lets see if i can get any of them..
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #397 on: December 06, 2024, 01:56:52 pm »
What shall we do next?
Where are we heading towards, its all dark ahead, we need some candles or some lights.
 

Online drhex

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Re: What more i can do?
« Reply #398 on: December 06, 2024, 02:06:45 pm »
So you tried known good EPROMs in the broken board, correct? If the address bus shows deviations after start and that is always the same, wrong data must be read causing wrong addresses on the bus or the board branches into different code (NMI stuck or similar). Have a look at the data lines and do the same thing as with addresses (will be easier with a logic analyzer). Have you checked the address lines at the EPROMs? Same signals as at the CPU?
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #399 on: December 06, 2024, 02:12:49 pm »
Have you checked the address lines at the EPROMs? Same signals as at the CPU?
Those above all are address lines and data outputs of EPROMS.
CPU, is there a connection between EPROMS and CPU? I have not check and think from that side.
 


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