Hey Jeff,
Check the FPmini Wiki site. It uses all the same TTL parts as the
original Imsai.
I would not trust N8T97B from eBAY. You never know what your getting.
The N8T97B can be substituted with 74LS367.
The i8212 can be substituted with SN74S412
Always use 74LS123 for the one-shots.
I have lot's of these parts and complete sets of IC's if you need them.
Contact me off-list if interested.
Anchor Electronics is the only real one source stop for these parts.
http://s100parts.com look under the kits category.
On 02/25/15 08:59 AM, Jeff Albrecht wrote:
I'm attempting to restore an Imsai front panel (FP) handed down to me
by my Father. I've used the chassis back in the day with a reset
switch wired to a proto board with mostly CompuPro hardware. I believe
Dad had the FP working with a Tarbell controller. Now I've dug out the
front panel and would like to restore it and the entire Imsai 8080 to
functionality. I believe I have the original Imsai boards. I've
already rebuilt <http://www.rodaw.com/imsai-power-supply-rebuild/>the
power supply. And have one of Josh's 8080 cpu boards running in it. So
reset and run work! I also have an Imsai front panel simulator
<http://www.autometer.de/unix4fun/z80pack/index.html> running in a VM
to remind me of front panel operation.
I have the original Imsai documentation. I scanned the FP parts list
and OCRed it into a spread sheet.
8T97 1 Hex Tri-State Buffer/N8T97B
7400 2 Quad 2 Input NAND/SN7400N
7402 2 Quad 2 Input NOR/SN7402N
7404 1 Hex Inverter/SN7404N
74LS04 2 Hex Inverter (Low Power Schottky)/SN74LS04N
7405 5 Hex Inverter Open Collector/SN7405N
7410 1 Triple 3 Input NAND/SN7410N
74LSI0 1 Triple 3 Input NAND (LPS}/SN74LSION
7427 1 Triple .3 Input NOR/SN7427N
7430 1 8 Input NAND/SN7430N
74LS30 1 8 Input NAND (LPS)/SN74LS30N
7805 1 SV Positive Volt Regulator/MC7805CP
8212 1 I/O Port/P8212/S1002
74107 3 Dual J-K Flip Flop With Clear/SN74l07N
74123 3 Dual Monostable Multivibrator, Retriggerable with
Clear/SN74123N
I thought I would lay in a set of spare parts before I begin. I can
get most of the parts at Jameco less expensively than DigiKey, however
DigiKey has specific versions of parts that Jameco does not. The
N8T97B I found at Wholesale Electronics, Inc <http://www.weisd.com/>.
crossing to a NTE6887
<http://www.weisd.com/test/WEISD_TBL_view.php?editid1=NTE6887>Didn't
see it at JameCo or DigiKey. FWIW I've attached a Jameco cart as
jamecoImsaiFpList.csv
I'm inclined to repair the board with available parts but am thinking
a bit about whether I should restore it with all original parts. Would
that be better for a donation to a university or museum or just
preservation of historically significant hardware?
What substitutions can be made for 7404/74LS04. Will the LS version be
suitable for both parts? The parts list also calls for separate 7410
and 74LS10, as well as separate 7430 and 74LS30.
Although reset and run work, it looks like examine and deposit
circuits are having difficulty. With all switches down I don't appear
to be able to deposit to zero, nor examine. the [deposit | examine]
next seem a bit flaky but may be due to the [examine|deposit] not
working correctly. So far I've tested all the switches. I had to open
one up and clean the contacts. It appears to be working now. I
replaced a couple LEDs, bummer that they are a bit more clear and
consequently brighter but not extremely noticeable with plastic FP
installed.
I've read the CP-A rev. 4 construction and operation portions in the
documentation. I found these threads
http://fixunix.com/cp-m/50-imsai-troubleshooting-hints-faqs-etc.html
and http://ana-3.lcs.mit.edu/~jnc/cctalk/2001-September/1400.html with
some tidbits. Anyone know of other resources I might want to review?
Some help nailing down a parts list would be appreicated.
Thanks! - jeffa
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