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EPROM 27C128 wrongly put in IC socket

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DrWhoF

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put eprom in wrong

The board consists of 27C128 eprom, HM6264 ram, 74LS373 and NEC D78310 microprocessor.
Eprom was installed the wrong way and then the right way but board doesn't work any more.
I tested eprom and it still has its data.
Question: which of components has given up???
 

ic socket bad

How do you know it is still alright?
A chip is usually destroyed if it is plugged in backwards ..

Regards,
IanP
 

    D

    DrWhoF

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as Murphy´s Law applied to electronics, the expensive one. But, instead of data is in eeprom, look inside, and try to see if some wire is broken. Probably the EEPROM i said. good look

Breno
 

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    DrWhoF

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Well, I compared eprom with a hex file.
How can I verify that microcontroller is workig?
 

Yes, you can. Go to data sheet of uC and there is a section named Test. Normally is putting some resistor and some capacitor to a couple pin. Or, Do a program that just turn ON a LED, or blink a LED in each program cycle, or something like that. If the uC is ok, do a program and try to access the RAM module. If nothing happens, bingo, you found your problem!!

best regards

Breno
 

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    DrWhoF

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I can see (oscilloscope) oscillations but nothig is happening besides that.
I'm not at all familiar with D78310 mirocontroller and I couldn't find data sheet.
What should I do next?
 

Mate,

For me the EPROM is dead ..
I haven’t seen one of that brand [27(C)xxx] that after being plugged in backwards would still be usable ..
If you have the correct HEX file burn new EPROM, plug in the right way and see how it goes ..

Regards,
IanP
 

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    DrWhoF

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its not possible for the eprom to work any more after being installed backward. I think you are mistaking in comparing your hex file, it would not take more than moment to burn out if it is installed wrongly.
 

    D

    DrWhoF

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You are right: the EPROM is dead.
 

EPROM should be always 0xFF after wrong direction power on. unless ERPOM is just shift, not wrong dir.
 

EPROM burn instantly when you put it backward in socket
i know this from bad experience - it's dead

best regards
stroma
 

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