ah, this makes sense - the device (Ensoniq EPS16+ performance sampler) was released around 1990 and as I just discovered, that number is also printed onto the board.In fact I didn't find any reference to the chip numbers you mentioned. But be aware of the possibility that the codes 9051 and 9052 can be production data, i.e. the weeks 51 and 52 of 1990.
It's 9051, so you're suggestion that these are production dates makes sense.BTW, in your text you wrote 9051, but in the subject 9501. Which one is right?
There's a few more numbers on each chip - I doubt it'll help a lot if these are custom chips, but who knows...
NEC:
9051PD
7538AC044 1380753801
National Semiconductor:
+B9052
MM58241N
both are 40pin DIPs
The display itself has 42 pins - 2 groups of 10 at the top row, 2 groups of 11 at the bottom row. It has 22 alphanumerical 12-segment characters and a number of custom words.
The display board communicates thru a serial line with the mainboard. I tried to decode the data flow, but it's too convoluted. I'm not trying to repair the device, rather I'm using it as a basis for a new instrument where I would like to re-use some of its original components, mainly because of mechanical issues (in other words: while it would probably be easier to simply buy a new display it would mean to build a new front panel too).
If it is a microcontroller + a display driver as was suggested (and this makes sense to me), then it's probably easier to do away with them and just re-use the display.
thanks much for your help
best,
Sukandar
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Author: Sukandar Kartadinata
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