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Electronics => Repair => Topic started by: olliisit on May 21, 2015, 01:34:25 pm

Title: Pinout EPROM MSM3758
Post by: olliisit on May 21, 2015, 01:34:25 pm
I have an older German made milli ohm gauge.

I wanted to save the Firmware of this device , but the EPROM OKI MSM3758AS (M3758AS) is unknown by my programmer.

Maybe the EPROM is compatible to standard types  - but i could not find a datasheet or Pinout.

Could someone help ?
Title: Re: Pinout EPROM MSM3758
Post by: amyk on May 21, 2015, 02:17:37 pm
When was it made? Youi can try looking at these: http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/ (http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/)

...but at least from the '82 and '86 ones it seems a 37xx is RAM, not ROM.
Title: Re: Pinout EPROM MSM3758
Post by: wraper on May 21, 2015, 02:23:25 pm
Quote from: amyk on May 21, 2015, 02:17:37 pm
When was it made? Youi can try looking at these: http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/ (http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/)

...but at least from the '82 and '86 ones it seems a 37xx is RAM, not ROM.
(http://i.ebayimg.com/00/s/NTAwWDUwMA==/z/gcgAAOxyLm9TGPBU/$_12.JPG)
Title: Re: Pinout EPROM MSM3758
Post by: wraper on May 21, 2015, 02:31:59 pm
Could be compatible (at least for reading) with 2758 eproms.
Title: Re: Pinout EPROM MSM3758
Post by: wagon on May 24, 2015, 11:52:16 am
Quote from: amyk on May 21, 2015, 02:17:37 pm
When was it made? Youi can try looking at these: http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/ (http://ftp.df.lth.se/pub/bitsavers.org/pdf/oki/_dataBooks/)

...but at least from the '82 and '86 ones it seems a 37xx is RAM, not ROM.
What a ripper resource.  Thank yoU!
Title: Re: Pinout EPROM MSM3758
Post by: olliisit on May 24, 2015, 12:57:26 pm
Hello all ,

Sadly the Problem is not solved.

I get my hands on a old Data I/O 288A Programmer which supports 2758 Devices.

I used the old programmer with a really old PC with MS-DOS - but i coud not establish communication with the programmer.

After all i found the solution about the correct Interface cable pinout.
See attachment for a working ! interface cable.

The interface cable which was part of the programmer i got was not working (incorrect pinout).

But even these old programmer cannot read the MSM3758 EPROM.
The ..2758 devices i tried leads to a read error.

i tried several other eproms i have - reads all without problems (& file saving). --> programmer is working correct.

The gauge i have is working --> Original EPROM is intact

Maybe the device have a special Pinout or whatever .

So i am still looking for a original MSM3758 datasheet to narrow down my problem



Title: Re: Pinout EPROM MSM3758
Post by: amyk on May 24, 2015, 01:57:47 pm
Try asking Oki, or reverse-engineer how it's connected on the original device. If it's connected to a CPU it should be relatively easy to determine the pinout.