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National old IC ???

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spec

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Hi ortiko,

What is the weather like in Athens today?

The chip that you show has a National custom number so getting that number part would be impossible.

But we may be able to find a functional replacement, provided it does not have a special function too.

We would need a schematic from the service manual or if you could trace out the printed circuit traces and draw a circuit that would do.

Why do you want to replace the chip though?

spec
 

ortiko

Member
Hello spec


The weather today is cloudy and maybe it will rain a littlebut the temp is 20 celsius hot hot hot!!! ;)

I want to replace it because:
Near this ic is the lm339 ic. It warmed alot and the voltage at vcc pin was 2volt.

Replaced the lm78l82 and voltage is 8.2 V. Also replaced the lm339 IC but the pcb is not functional...
Suppose that this 051-9852 ic is off and if replace it will do the job.

Attached for you to cheack please is the other side of pcb
Thank you alot for helpingpcbdown.JPG
 
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Ian Rogers

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I have a feeling its a special.... AB may be Allen Bradley who did motor controllers... If this is the case this is probably a GAL which would need programming... BUT!! references to B9130 yield programmable power supply chip...
 

Nigel Goodwin

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I would imagine it's most probably a custom chip, and is a programmable device as well - so the only source would be a direct replacement from the manufacturer.

Interesting it's a 20 pin device, which is fairly uncommon.
 

spec

Well-Known Member
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Looks very much like the National Semiconductor logo to me.

spec
 

spec

Well-Known Member
Most Helpful Member
I would imagine it's most probably a custom chip, and is a programmable device as well - so the only source would be a direct replacement from the manufacturer.

Interesting it's a 20 pin device, which is fairly uncommon.
Yeah, I thought that. The early 20 pin packs tended to be octal bus drivers/transceivers: 74xxx245 etc

spec
 

ortiko

Member
ust for reference i have purchased a used pcb from the garage technician that installed in first place the door before 25 years an he charged it to me for 120 Euros :mad::mad::mad:
I could not wait any more. The door was unlocked.
At ebay someone sells it for 50$

Thanks everyone for posting helpful answers
 

spec

Well-Known Member
Most Helpful Member
Good news that you have got the garage door working again:)

spec
 
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