23 Nov
2001
23 Nov
'01
1:27 a.m.
Well, it sounds like it's less likely that you'll break the parts in your
tester, but it seems unlikely you'll be able to test the 4116's in it.
I got the mistaken impression that you had the HP test-clip type of IC tester,
of which I have a few, which require a functional component against which to
compare the function of the circuit under test. I've never figured out how
these work, since most of the ones I have are already brokent. One of these days
...
Dick
----- Original Message -----
From: "Tothwolf" <tothwolf(a)concentric.net>
To: <classiccmp(a)classiccmp.org>
Sent: Friday, November 23, 2001 2:21 AM
Subject: Re: 1771 floppy controller questions
On Thu, 22 Nov 2001, Richard Erlacher wrote:
From: "Tony Duell"
<ard(a)p850ug1.demon.co.uk>
The tester set I have is designed for out of circuit use. Both units are
labeled 'ramcheck' and list the manufacturer as Innoventions, Inc.
Houston, TX. The tester supports 64k and 256k according to the label. I
opened up the tester, and found it contains an AMD 8088, a 27C32 eprom,
and a single dram chip, along with a mix of 74LS ttl logic chips. From the
looks of it, I could modify it to support 1024s and likely support older
chips if I design some sort of interface board. The speed checker unit is
designed to be used in-line with the tester (or maybe in circuit?), as it
has a ribbon cable with dip idc header on one end. It has a knob for
voltage selection labeled; Off, 4.5V, 5V, 5.5V, NR. I'm not sure what the
NR stands for, maybe no regulation? The other control is a 16 position
rotary switch (0-15), which is used x10 for speed selection in ns. Its
logic board contains a 7805 regulator, a handful of 74LS ttl, and a few
other chips I'd need to look up in a databook (Possibly a PROM and some
clock generators?)
-Toth
Most (all?) DRAM testers that I've seen test
just the chips/simms out of
the circuit. It makes sense, since that way they can drive the address
lines, RAS/, CAS/, etc and veryify that the RAM works correctly on all
locations, etc.
HP made a series of device testers that live on a test clip that you
plug on in-situ, and if it's designed for one set of supplies, and you
hook up another, you may not be pleased with the results. I've got a
few of those out-of-circuit testers, but the one I thing he (Tothwolf)
is using is one of the type I'm referring to. It would be a shame to
damage one, as it can test a soldered-in part without first
unsoldering it.