Notes on Repair of ABI Chipmaster w/ Version 2.0 ROM from approx 1995 I purchased this tester used from an International seller on big-auction site. It had a tamper-proof seal placed by the seller over the 2 halves of the case. It was missing a screw and several other screws were partially unscrewed and one screw was very unscrewed and sticking up. Also the green wire was completely disconnected internally and one component is obviously charred and burned. I tell you these details because that means the seller knew there were issues and was obviously disassembled and then reassembled. However the ad was for a used working tester - which it was not working. I took some photos of the wiring as it was originally from the seller. It took me 2 days of research and downloading alot of PDF files and figuring out that the part labeled SUP1 is a protection device. I looked at the charred remains and found part number when viewed with a pocket microscope. F ("F" in italics means Fairchild brand) T051 and the next line read BE FT051 BE and this device I could find no informtion on it. My hunch is that it is a TVS Transient Overvoltage Surge Bilateral/non-polarized Diode. But I could be mistaken. I could find no voltage records for this device- so I really dont know what voltage it is - I would guess that it is a 6Volts TVS since the DC POwer requirement for the IC Tester is 6V 300ma - so if I were to replace this device I have a hunch a TVS 6v 500ma bilateral non-polarized would work. DOnt get mad at me if I'm wrong- use this information at your own risk. But that is only a hunch- I decided to just remove it by desoldering carefully and cleaned up the PCB underneath. I found that the copper traces underneath were lifting up and charred and so I decided to just carefully remove the part and do little else to it. SOmetimes fiddling with something makes it worse - so it is best to do as little as possible to it when charred. I just carefully cleaned it and scraped off the charring carefully with a blade very carefully- to reduce the chance of carbon short across the copper traces. I replaced the wires as they were boogered up. The green wire is negative (minus -) and the PCB is labeled where the minus should go. SO here I am 2 days after receiving this item writing the solution ( Great ... it now works hurray!!!) - maybe it will help someone else. I would not run this ABI tester on a power adapter without the TVS 6v 500ma part installed. I certainly would not run the ABI tester with any OLD AC power aDAPTER. Let me repeat myself - if you plug in a power adapter which is non-regulated then you will blow out your ABI tester. Do not use just any ordinary power adapter - I'm warning you. That is what happened to the seller - they used either a wrong polarity power adapter or non-regulated. See this TVS basically sits across the + and - battery terminal and if the voltage exceeds 6V then it blows. Iti s not a fuse - see a fuse wen it blows creates an open. But a TVS when it blows creates a short across the battery + and - terminal. I measured my blown TVS and it reads 390 ohms. I'm sure it get very hot sitting across the battery terminals. The plastic outer case melted and charred an dbubbled up. See my photos. This tester is safe to use on AA batteries and I will use it on batteries only. I will try to replace the TVS but since my PCB is charred what I think I will do is simply solder the TVS across the inside of the DC power jack + and - terminals. I have to find a regulated AC power adapter - most power adapters when you plug it into the wall - and you measure it with a volt meter are greatly exceeding the voltage written on the power adapter body. You cannot use one like that. You must take your voltmeter and make sure that th eAC power adapter yoy plan on using measures no more than 6v. It must be accurate or you will blow your IC tester. The moral of the story is - USE BATTERIES only on this IC tester. It does not have an internal Voltage Regulator. I suggest you install a voltage regulator as a DIY project. I was fortunate - in this repair - that I presently have a high skill level for repairing items otherwise this story would have had a totally different ending. That skill was acquired thourgh many years of soldering and tinkering and disassemvbling and fixing and you name it. I learned the hard way - through many years of self-teaching and repairing of all kinds of devices both simple and complex. The seller skunked me by selling a bad item - however I turned it around and fixed it - so it really was a bargain now that I have a working tester. But really the seller wrote a dishonest ad and advertised a working item. It is unfortunate taht seller are often playing games. Several of IC tester arrived non-working and I had to fix them. The actual repair was easy - but knowing what to do and how to do it - takes skill - and I hope that this writup helps someone with a similar problem. Dr Virago Pete drviragopete.com See my webpage http://www.drviragopete.com/electronic-parts-testing-service.php