Author Topic: What more i can do?  (Read 36985 times)

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Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #200 on: November 18, 2024, 05:46:00 am »

Someone also thought IC7 could be the fault.

IC7, Have not check IC7, Its an AND gate logic, data seems good.
If you want i can check again.
What you exactly need from IC7?
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #201 on: November 18, 2024, 05:52:07 am »

"I checked all capacitor, no sign of short, the IC looking good, no burn marks as well as any damages."


First I checked physically if there is some breakage or burnt mark in capacitors.
Then I shorted the capacitor, and measure capacitance with digital multimeter.
Later someone on forum told to desolder capacitor, i desolder and measure them, seems good to me.

I have no ESR Meter.
 

Offline Harry_22

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Re: What more i can do?
« Reply #202 on: November 18, 2024, 06:19:50 am »
After some cleaning and resetting the CMOS Battery and shorting it, I get D Flip Flop same in Both Working and Not working one.

Hi!
Don't worry, it sometime happens.
Compare again the logic on working and non working machine.
You are lucky that have both boards to compare.
Check also the TP (test point).
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #203 on: November 18, 2024, 06:26:40 am »

Compare again the logic on working and non working machine.

Check also the TP (test point).

Do you want me to check remaining pins of IC6 D Flipflop?

TP2 is negative terminal, TP1 is positive terminal, What more i should check.
They are just sorted with the power input pins.
Could it be they have some other purposes?
 

Offline Harry_22

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Re: What more i can do?
« Reply #204 on: November 18, 2024, 06:34:52 am »
Compare again the pins marked by green arrows. Just to shure that no difference in signals exist.
 

Offline Harry_22

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Re: What more i can do?
« Reply #205 on: November 18, 2024, 06:47:36 am »
About our current strategy when we have both good and bad devices available. Gradually separate the good nodes so that at the end the fault remains.
Look carefully for the slightest differences.

PS
As we have already seen, something goes wrong immediately after releasing the Reset line. The BIOS doesn't even try to boot.
« Last Edit: November 18, 2024, 06:51:55 am by Harry_22 »
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #206 on: November 18, 2024, 07:05:27 am »
Compare again the pins marked by green arrows. Just to shure that no difference in signals exist.

All are same, i double checked.
 

Offline Harry_22

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Re: What more i can do?
« Reply #207 on: November 18, 2024, 07:09:05 am »
One more please check.
On switched off machine measure /compare the signals (frequency also) on pin 11 of RTC chip.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #208 on: November 18, 2024, 07:33:40 am »
One more please check.
On switched off machine measure /compare the signals (frequency also) on pin 11 of RTC chip.

First is Non Working
Second is Working.

I do not see frequency in working board, maybe division issues.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #209 on: November 18, 2024, 07:58:03 am »
TP ? What is TP here?
Is it Test Point, Or is it Timing Pulses for RTC?

The TP2 is shorted to GND here, and TP 1 is connected to resistance and then VCC.
 

Offline Harry_22

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Re: What more i can do?
« Reply #210 on: November 18, 2024, 08:01:53 am »
Yes, a strange case. The working does not work and vice versa. Could it be contagious?
 In any case, we dug up something. We have to think.
 

Offline Harry_22

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Re: What more i can do?
« Reply #211 on: November 18, 2024, 08:41:53 am »
TP ? What is TP here?
Is it Test Point, Or is it Timing Pulses for RTC?
Was it me or you who asked? :)
Seems the Test Point.

The TP2 is shorted to GND here, and TP 1 is connected to resistance and then VCC.
Please check TP2 Gnd connection on both boards.
Next have a look on TP1 signal as usual.

Check and compare the battery voltages.
« Last Edit: November 18, 2024, 08:45:08 am by Harry_22 »
 

Offline Harry_22

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Re: What more i can do?
« Reply #212 on: November 18, 2024, 09:14:32 am »
Please check the Pins 9, 1, 2, 3 (see the picture attached)
It seems we have already looked at the other signals and they are the same (better double check).


PS
For me it is look like Watchdog timer on Pin11.
« Last Edit: November 18, 2024, 10:29:00 am by Harry_22 »
 

Offline Harry_22

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Re: What more i can do?
« Reply #213 on: November 18, 2024, 10:36:09 am »
Before I forget.
Attach the trace from continuous beeper. We will look for 63 Hz presence there.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #214 on: November 18, 2024, 12:53:26 pm »
The thing i ask about TP is because in RTC datasheet its written Timing Pulses.

So TP 11 PIN RTC is Timing Pulses and TP1 and TP2 is Test points, am I right?

TP of RTC is Input or is It Output data?
Can you explain this picture, whats the text mean?
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #215 on: November 18, 2024, 12:57:00 pm »
Before I forget.
Attach the trace from continuous beeper. We will look for 63 Hz presence there.

Please Explain in details, I does not understand lots of things, still begineer and learning.
 

Offline Harry_22

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Re: What more i can do?
« Reply #216 on: November 18, 2024, 02:44:48 pm »
The thing i ask about TP is because in RTC datasheet its written Timing Pulses.

So TP 11 PIN RTC is Timing Pulses and TP1 and TP2 is Test points, am I right?

TP of RTC is Input or is It Output data?
Can you explain this picture, whats the text mean?

I understand. It's good that you asked again. Sometimes I don't even understand myself.

Don't mix abbreviations from the board and datasheet. They are different.
TP on the board is a Test Point.
TP in the datasheet is a Timing Pulse.

Look at some further explanations in the drawing.
The drawing is the language of engineers (my German teacher used to say that).

I will make the detailed explanation later on. When I see the full picture. Sorry.
And now we are only collecting information on RTC, you are my hands and eyes. Don't let me down!

Regarding Beeper.
Make the same measurement on its signal pin. Next one pin is +5V or GND.

« Last Edit: November 18, 2024, 02:49:39 pm by Harry_22 »
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #217 on: November 19, 2024, 12:25:18 am »


Please check TP2 Gnd connection on both boards.
Next have a look on TP1 signal as usual.


TP2 GND connection is good, same in working and non working board.
TP1 Signal is below, Its look same as RTC 11 PIN where non working has frequency and working doesnt have,
1st Image Non Working.
2nd Image Working.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #218 on: November 19, 2024, 12:35:51 am »
Please check the Pins 9, 1, 2, 3 (see the picture attached)
It seems we have already looked at the other signals and they are the same (better double check).


Here, these are similar to both Working and Non working board.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #219 on: November 19, 2024, 12:36:45 am »
...
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #220 on: November 19, 2024, 12:51:57 am »

Regarding Beeper.
Make the same measurement on its signal pin. Next one pin is +5V or GND.

1st Image is Non Working
2nd Image is Working.

Next one pin is +5V.
 

Offline Harry_22

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Re: What more i can do?
« Reply #221 on: November 19, 2024, 01:40:51 am »
I expected to see the high level on C2.

Please try to lift leg 11 of the RTC chip on non- working machine.
Let's do the following. Apply flux to the leg and braid for desoldering. Touch the braid to the leg and remove all the solder with the soldering iron. Next slip a blade under the leg and touch the leg with a soldering iron. Don't lift it high, it might come off.
 Next look the signal at TP1.
 

Offline Harry_22

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Re: What more i can do?
« Reply #222 on: November 19, 2024, 01:46:53 am »
Try to switch on non-working machine without the battery first.
Control TP1 signal as usual.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #223 on: November 19, 2024, 02:01:14 am »
Try to switch on non-working machine without the battery first.
Control TP1 signal as usual.

Same before battery remove and after remove.
 

Offline 222Lab_Test222Topic starter

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Re: What more i can do?
« Reply #224 on: November 19, 2024, 02:24:16 am »
I expected to see the high level on C2.

Please try to lift leg 11 of the RTC chip on non- working machine.
Let's do the following. Apply flux to the leg and braid for desoldering. Touch the braid to the leg and remove all the solder with the soldering iron. Next slip a blade under the leg and touch the leg with a soldering iron. Don't lift it high, it might come off.
 Next look the signal at TP1.

I do not think it can be done,Why?
Because its old board and too ,much testing has been done in that pins, If i did further and try to desolder i worry it might break down.

BUT i will try if it can be done, Lets Hope.
 


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