27 May
2013
27 May
'13
5:48 p.m.
On 2013 May 27, at 2:00 PM, Dave wrote:
On 27/05/2013 19:19, Brent Hilpert wrote:
They were used extensively in the address decoders and drivers and
inhibit drivers, even or more so in later systems. To my observation,
early systems may use them in the sense amps, later systems avoided
them there in favor of all-IC sense amps. In address decoders they
simplified the circuitry by sitting at the intersections of decoding
matrices, in drivers they were a simple solution for isolation and
level-shifting.
I don't know that there was anything special about them, other than
finding a particular match. The junked board I was looking at has 3-4
different types. Looking at Digikey there are far more types still
being made today than I was aware of, so maybe there's a fair chance
of finding modern matches.
..
The 2624- numbers appear to be Burroughs house numbers as I think
the board is from a Burroughs machine, the 79xx/78xx date codes.
I wonder if NPI was the transformer manufacturer. I RE'd the board
so I do have a schematic that shows how they are used but don't
know anything about their specs beyond that.
It looks like they are the Manufacturers.
http://www.trademarkia.com/npi-73366630.html
and some product here:-
http://www.electronicsurplus.com/Item/3274-1.jpg
but it looks like the company is long since dead.
As I suggest in another message, another possibility might be to
investigate ethernet-isolation transformers.
Whats special about Core Memory Transformers that means generic
pulse transformers can't be substituted? Aren't they there to
detect the sense pulse...