nec ca245c replacement

"dron" Hi

** What is stopping you from describing them ????

What package type - how many pins etc ??

........... Phil

6 Pins old can type IC a bit smaller diameter than a 5 cent piece

Darren

** Sounds like a TO5 style package.

Likely to be dual transistors or dual fets with 6 pins.

Normal op-amps all have 8.

The numbers all come up blank on Google - so just how antique are they ??

............ Phil

The Crain is from 1985 but the electronics look old even for that time. I have the pick up at a local industrial tecks workshop and am going by memory on the pin numbers. The unit compares 2 inputs from mechanical pressor sensors and gives a single output. Runs from a 12v +/- supply and gives a dc +/- output to the weight scale. The bord is about 50mm by

75 mm in a steel case. 1 new one left in the world and they want $6000 for it.

Hi, could be upc254a - instrumentation amp, as far as my data sheet indicates , it has 8 pins in both dip and can type.

if that's it, datasheet can be found here for a while:

http:// members. iimetro .com .au / ~gcd / upc254.pdf

Can't find any nec reference with 1541 or 1541a, any prefix on that like d etc?

Greg

On Sun, 13 Mar 2005 08:41:48 +1030, dron put finger to keyboard and composed:

You have "ca245c" in the subject but "c254a" in the body of your message. Now you are not sure of the numbers of pins??? Not meaning to offend, but maybe you should confirm all the data before you have us looking for something that never existed.

It may help to know which pins connect to what, ie inputs, outputs, supply rails. I suspect the first IC may indeed be an 8-pin instrumentation op-amp. If so, then maybe you can substitute an OPA111AM (Farnell, p/n 400-671, $47) or better.

See

Is it possible the 1541 is really a 1741? If so, then it's probably a general purpose 741 in a TO-99 package.

- Franc Zabkar

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Please remove one 's' from my address when replying by email.

C254a and c1542 are the correct numbers. I will call the teck that has the unit to check the pin numbers Monday. He told me they should be op amps. The numbers were good and did list on 1 of his suppliers sights. Their was no data on them or local availability though.

Dont pretend to know a lot mysealf but the if the link to the pdf from Franc Zabkar is corect it will help

Thanks I will post the corect pinout asap

"dron" <

** They could easily be factory code numbers - secret by intention. ** It is the ***number of pins*** we want to know - you illiterate prick.

BTW The abbreviation for technician is " tech " !!!!!!

** So it is all bloody hearsay !!!

............. Phil

Hay toasterboi still falating roddles each evening in the loo down queens park ? I hear you two go pretty hard at the anal right around 8 pm ?

dont ask phil, all he does is insalt everyone.

Don?t worry every group has one like Phil. I reply to a question or two in the aus.car group in the interest of helping people from within my field and it seems there is plenty of those who think they are to good or maybe to insecure to play nice.

For those who don?t fall into this group I checked out a 2nd unit today ( also faulty). It was older but the same design. The IC?s were the same ( 2 of NEC c254a and 1 of c1541 ) and sorry they do have 8 pins. A 12v

+/- supply and the older board is marked op amp 1 2 and 3 so I guess they may in fact be op amps. If anyone has an old crossover book listing an equivalent that would be grate.

Thanks

On Mon, 14 Mar 2005 21:30:28 +1030, dron put finger to keyboard and composed:

Your statement that "the unit compares 2 inputs from mechanical pressor sensors and gives a single output" suggests to me that the uPC254A, an instrumentation opamp, amplifies the output of each sensor, and the uPC1541 is probably a general purpose opamp wired as a differential amp. A little bit of circuit tracing should tell you whether you could substitute a 741 or better for the latter, and a suitable low offset, FET-input, low bias current equivalent for the former.

BTW, the OPA111 opamp I alluded to elsewhere differs from the uPC254A in the offset nulling pins. Check whether your circuit uses these before attempting a substitution.

- Franc Zabkar

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Please remove one 's' from my address when replying by email.

been there long enough - gone now

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