Somehow this unit is affiliated with MicroSciences brand tester as I see online a resume from a person who formerly worked at both companies. I emailed this person years ago and although he remembered nothing technical regarding these units- he did confirm that there were a few core people who help develop / build both units. BUT AS I SEE IT in looking at the units and using and fixing these units - they are VERY different layout, parts, and options are all built in on the BoardWalker 103 v2.0 while my 3ea identical MSI ICT-101 units have no hardware options built-in. My opinion - the units are so different that I needed to add this BoardWalker to my collection of daily use testers. I value the second opinion of any tester as it reduces my need for desoldering and troubleshooting time. There are very few in-circuit IC testers ever made. Sometimes this in-circuit testing is called "backdriving" and has this function built-in. A word of caution about in-circuit testing is that (although I dont have the manual yet) the test clip should not be connected to the IC for a prolonged period of time - under a minute is what I suggest. No dilly-dallying, talking on the phone, other distractions - the test clip puts stress on the chip and the tester itself. Leaving the test clip on for over a minute CAN damage the IC or the Tester. I learned this from the MSI ICT-101 manual (which the former developer person worked at both firms- probably have some similarities) SO what Im saying is there is a pretty high probability that this is also applicable to this tester. DONT LEAVE THE TEST CLIP ON LONG. Another thing I learned from the MSI ICT-101 is that power switch "bounce" can blow out the tester- happened to me? So pay attention to the moment you press the power switch- make sure you dont wiggle or jostile or double-press etc. I spent alot of effort troubleshooting my ICT-101 units (see above) The circuit under test needs to be powered-on but not running. The Circuit needs to be checked to verify Voltage is no more than 5V. For example 6V will kill the tester. Circuit under test can have CPU removed or Oscillator crystal removed - thus leaving the circuit without clock pulse. The chip under test must be Powered On and idle. I hope I have explained that in clearly understandable laymans everyday terms. This tester cannot test a running/pulsing/logic-state-constantly-changing chip. The logic state of the IC must be idle and not fluctuating- hence the need to remove clock signal or oscillator crystal etc. Hooking tester up to a live oscillating circuit can damage the tester or the circuit. This is my 15th IC tester. And my 3rd model with in-circuit testing capabilities. I have not yet built a chiplist for it. This unit has a Zif Socket on the front panel where an add-on ROM chiplist can be attached. The LCD Menu can select whether the internal ROM chiplist or Externally connected ROM chiplist is used. I dont have any external ROMs for it. When I purchased it used - it was just just the unit itself. I made my own cables as my unit was purchased used and didnt come with any cables. I currently have only made up one 16-pin test clip and ribbon cable for it. ITS A BIG BEAST IC Tester (about the size of a Mid-size ATX Desktop PC Case) - but worth the benchtop space as it is very capable. I dont have a manual for this - let me know if you have a manual (any model 100, 101, 102, 103) for sale for this unit. I didnt see any online manuals for this unit. My Repair Notes Mainboard is model 102 and has 103 Roms installed. Rear mfg sticker shows model 103- so having a model 102 mainboard and model 103 ROMs is normal. My unit came from seller in semi-working condition. The unit self-tests good/menu and keys work but gives an error when testing an IC in its test socket- saying that the test chip does not match its internal data. I opened the case and found a piece of plastic and a mounted IC chip (before ever powering up I checked for anything loose or odd) which was probably some random scrap that fell in there by the previous owner. I dont see any homemade-looking soldering. Case lid was missing screws, daughter board missing one washer. Lots of 75441? chips (16ea= 2 rows of 8ea) which are socketed. Yikes - Even with my vast collection of 14+ IC testers of various models/brands - not one of them tests 75441?. It is printed very strangely on the chip itself "75441 then a vertical line then NE". So maybe Im reading it wrong? I need to see if one of my testers can identify it. The way it is printed on the chip is very odd. One ROM chip had a missing sticker and exposed window. I used an aluminum shiny notch cover/write protect sticker from my box of old 5-1/4" floppy diskettes from the 1980s. I used this aluminum sticker to cover the ROM window on both ROMs to prevent erase/exposure to light. Some chips socketed but plenty of chips which are just soldered to the board. The IC test socket has a slight wiggle but solder connections look strong and unblemished. There are no similarities internally between Boardwalker and ICT-101 - totally different - in my opinion. During the self diagnotics, several menu settings can be used to test various parts of the machine. I went through all of these and it passed all self tests. I traced the IC socket to either the board directly behind the LCD display or to the mainboard. Since the 75441? chips are socketed and there are 2 rows of them- Is it possible the mfg socketed these chips for a reason - the likely event that the user may accidently hook up the clip wrong? My hunch is to first check the socketed chips especially since they look like a possble direct or near direct correlation to the socket and ribbon cable test clip. Self diagnosis has LEDs on front Bezel light up as internal functions tested. At some point the internal relays are heard to click. Menus and keys and self tests seem to run as normal with nothing odd noted. Seems to go through step-by-step self diagnostics successfully. Chiplist is accessible from the Menu and scrolling up/down to select which one to pick. The machine doesnt look tinkered-with or jerry rigged- but has telltale signs that someone was in there before. Wiggly IC socket may be a cold solder joint on other side of board - or a broken pin/leg on the socket itself? Update 9/26/16 As I try to figure out what the 75441? chip is - I see in the Menu/chiplist "754411" which would explain the odd vertical line in between 75441 and NE so - it stands to reason that the tester was made to test its own set of chips. As I tested one of the chips ( hopefully that one wasnt the bad one) - none of my other testers were able to identify it using the search function. As I researched what this chip is "2 channel Periph Driver or Inverter" or "Quadruple Half-H High Current up to 1A Driver" and downloaded PDF data sheet - It apears there are 2 identical halfs. Upper half and lower half of chip are almost symetrical electrically- nearly mirror image almost but not quite upper and lower half of chip - per internals diagram of data sheet. I think the only tester I own that can give me a clue about this - is by using Lissajous patterns and comparing the 16ea chips pin-by-pin. I see only one seller on big-auction-site selling for $16 each IC imported from UK. I checked to see if the Big Electronic online vendors sell these and I didnt find any sellers for this chip- only one seller on big-auction-site. So at least there is ONE source of parts and that seller shows NE after the part number - so it looks like an exact match. I need to figure out how to test them - using Lissajous patterns on my Beckman Scopemate2. It is possible to sense internal chip damage such as broken internal chip wires/damaged internal diodes etc. The good news is once I have this BoardWalker working - I will then be able to use this tester to expand my chiplist. Unfortunately - the non-working tester is only one that has this IC in its chiplist LOL. It takes a BoardWalker to fix a BoardWalker- hopefully I can use Lissajous patterns to see anomolies when comparing chips. Thank goodness they are socketed ic chips. Another option is piggyback a good chip over the chips one-by-one to see if there is a change in ic tester successful or continues to give same error? I was hoping that I could find a cheap source for this IC- and just replace them all - but this chip is kinda rare and pricey - so the replace-them-all-since-they're-ten-cents-each strategy isnt applicable. It is an obsolete hard to find part. Thank goodness there is one vendor. Update 9/29/16 I have successfully repaired - as far as I know at this point. I have tested about 12ea 7400 series chips with up to 20-pins using the built-in IC socket and see the LCD display "Passed Loose" meaning that it was an out-of-circuit chip "Loose" meaning not attached to a board. 1. Cleaned the IC Socket 2. Resoldered/lightly touched up the backside pins/legs solder joints - on ic test socket 3. Reseated all 16ea 754411 socketed ICs 4. Disassembled daughter board and reseated all connectors and tightened loose standoffs (previous repairman didnt put back snug) 5. Top cover missing screws replaced from my inventory/can of screws scavenged over the years. 6. Rattling around white piece of plastic enclosed IC which had no relation to this machine - dropped inside the case by previous owner (I found this before ever plugging it in) That repairman is probably wondering Hmm where did I put that thing I had it a minute ago LOL. 7. Metalized sticker to cover exposed eprom window I have the 16-pin IC test clip all ready to go but I need to purchase a header for use with ribbon cable in order to connect to BoardWalker front panel. I have not tested the In-Circuit capabilities so it is too soon to say it is 100% working. I got lucky that there was a cold solder joint/dirty connection/etc as after I cleaned and touched up solder joints and reseated parts and ribbon cables etc. I was glad to see the word Passed. It isnt a good feeling spend hundreds $ on a piece of test equipment and discover there is an issue. There is always a bit of LUCK and SKILL involved in a repair. In this case I was VERY lucky that the 754411 chips were not blown as I have no other test equipment to verify that particular IC. Reseating these chips (correcting poor contact or slightly oxidized/corroded) may have solved the issue. Judging by the telltale signs of a previous repair attempt - this stumped/perplexed the previous owner(s). It was purchased from a test equipment rental/repair facility at auction. I have included a photo of a PASSED chip - I was so glad after 2 days of work - to see that display. Incorrectly assembled IC Test Clips purchased from big-auction site seller I purchased 16-pin IC Test Clip with multi-colored Ribbon Cable from big-auction-site and I found that the inline connector is actually vise-versa backwards. If I connect a header then the rows of pins are backwards. So the mfg/factory made these wrong. That is an issue when buying stuff on big-auction-site - there is lots of "junk peddlers" as I swear and cuss after receiving one box after another of problematic purchased not-as-described items. Yikes. My solution is to make a loop-de-loop and connect the test clip to the incorrectly mounted inline connectors. I have included a photo of what Im calling a Loop-de-loop (its my invention - so I can call it whatever I want to LOL) One of the two that I purchased was sealed in the original mfg package. The second one was stapled shut and rubberbanded. I compared both and was identical. The only issue with a loop-de-loop is that it can interfere with pressing on the clip to open it up. It is better not to have a loop-de-loop interfering with your test clip. But nonetheless I needed a clip and these are hard to come by. To an un-trained eye (it looked correct but it is not) and the unskilled factory worker who did this - they probably messed up a whole lot of these and that is why the big-auction-sie seller has gotten ahold of these. My jerry-rigged "loop-de-loop" is shown in the picture (below) at right. Basically I disconnected the 2 inline connectors from the test clip - and made them do a U-shaped back-bend - then reconnected the IC Clip. The rest of the ribbon cable can either be fished through to the left or to the right - your choice. The factory error makes the ribbon cable's pinout 21436587... rather than 12345678... My Loop-De-Loop corrected this by making a backbend first and then connecting the IC Test Clip. Now that it works I can tell you that it tests chips very quickly and is almost instantaneous (for most chips) A few chips take quite a bit longer to test (it kinda looks like it is stuck on certain chiplist numbers- its not stuck - it just takes longer to test that particular chip) but then after a minute shows PASSED or FAILED. Scrolling through the menu and selecting the chip from a long chiplist is tedious BUT holding down the up or down button and continuous scrolling is a time-saver. There is an audible click with each passing IC while scrolling The ticks go by fast maybe 20 per second? It still takes time to find the IC in the chiplist. I dont have the manual. It does have a logic monitor function - used with the IC test Clip. So it is like having a logic probe. I havent tried or played with that feature. Im glad it uses ordinary common chips. Some of which have become obsolete or hard-to-come-by since 1991- for example 754411 is now a rare uncommon chip. I see no epoxied-over chips (the ICT-101 has epoxied over board) so this makes it - repairable/testable - since whatever is capable of going wrong is replaceable at the component level - as far as I can tell. Some functions I dont know how to use (such as Probe) without the manual. In my experimentation and trying to use this without a manual - I was able to figure out how to search. It is interesting that you can search for Logic and/or RAM and gives an onscreen warning that it may damage chips that have unusual pin position for Ground or Volt. My search test was very basic and it found 7400 logic chips - it took about a minute or just a moment each to find a few chips. The logic monitor function is selectable by number of pins on the chip for example 8-pin through 32-pin looks on the display like this HHHH OR HHHHHHHHHHHHHHHH OR HLHL HHHH HHHHHHHHHHHHHHHH HLHL Showing H for High or L for Low logic state At this time I have no idea how to use the Pulse mode. Searching for RAM is an interesting function and has a very few older type chips mostly Static RAM in its chiplist. Some ICs in its Chiplist shows the same chip# listed twice for example 74XXX Part 1 and 74XXX Part 2. At this time I dont what that means - it is possible the chip needs to be fully tested BOTH in Part1 and Part2. Or it could mean that it is for different brands which can vary just slightly? I can only speculate at this time on why? I tried a few chips on both Part1 and Part 2 and seems to PASS on both - for a known good chip. I did test a few known FLAKEY or known BAD chips (chips which I previously identified and I use these to test the testers) and I found a few that passed and a few that failed. I reserve judgement on what that means until I have a chance to get to know it better. My view is ALL testers are useful and using multiple testers is what I do. I value this testers second opinion and will be one of many testers which test each and every chip- to verify the health of the chip. This tester probably has a unique approach to testing chips - different from other testers in some way. The 25-pin Rear Port I see the rear 25pin connector (probably a serial RS232 port) has a cover over it - in which the cover is made from an incomplete 25-pin connector BUT minus all of the pins. It is then screwed on top of the actual port backwards. I dont know why they did it that way. The actual port has no metal shroud around it- hence the second pin-less connector fits over it. I dont plan on using the rear port. The jerry-rigged cover makes no difference. It is possible the rear RS-232 port has no metal shroud because that is a ground. The factory may have wanted to isolate it from the computer during communication? That doesnt make sense because the pinout of the serial port contains ground also. I havent figured out why it is that way- Im sure there is a reason- so I will leave it that way. It may be to protect the BoardWalker from homemade cobbled-together jerry-rigged computer systems of that era as the computer-age became personal/desktop/DIY.