Path: utzoo!mnetor!uunet!husc6!hao!ames!ucbcad!ucbvax!cbosgd!cblpf!cblpn!edo
From: edo@cblpn.ATT.COM (Eric Osborne)
Newsgroups: comp.sys.atari.st
Subject: Re: eproms burners
Message-ID: <534@cblpn.ATT.COM>
Date: 4 Jan 88 16:07:21 GMT
References: <903@PSUECLB>
Reply-To: edo@cblpn.ATT.COM (55214-Eric Osborne)
Organization: AT&T Bell Laboratories - Columbus, Ohio
Lines: 22

I don't have any recommedation on which EPROM burner to buy, but I DON'T
recommend the HIPPO eprom burner. I have one of those - it seems to work
reasonably well with EPROMS with a 21 or 24 volt programming voltage (2732,
2764) but the 12.5 volt chips (27256, 2764A, 27512) don't work. By the time
I had discovered this, the device was out of warranty. There is no schematic
included in the documentation, so I can't be sure, but I think the problem 
revolves around the Vcc (supply voltage) to the EPROM. On many EPROMS, such as
the 27256 and 27512, the supply voltage is supposed to be raised to 6 volts 
when programming the chip. The Hippo programmer doesn't appear to do that.
Anyway, I have NEVER been able to get the thing to reliably program a 12.5
volt eprom - sometimes it will program PART of the device, sometimes it won't.
The interesting thing is that it often shows verify failures on locations
which subsequently prove to be correctly programmed.


The opinions expressed herein are my own, and do not necessarily reflect those
of AT&T Bell Laboratories or Advanced Programming Resolutions (my real
employer).

Eric Osborne
{ihnp4, cbosgd}!ncpj!edo
(614) 860-2968