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Retro chip tester project

Discussion in 'd.i.y.' started by Tony L, Mar 9, 2023.

  1. bugbear

    bugbear pfm Member

    So this tester is (at core) a computer (microcontroller) with software specs of the the chip to be tested, and LOTS of buffered/powered bidirectional I/O pins?

  2. Tony L

    Tony L Administrator

    Yes, I think so. The list of totally different types of chips it can test is massive (loads of different RAM, ROM, logic gates etc, hundreds of different things), so I guess there is a lot of heavy lifting going on in the CPU and programming where I assume each pin of the ZIF socket can be assigned to pretty much any task or voltage. It is a remarkably cool thing. Just hope mine works when the final bag of transistors land!

    It should be really useful for tinkering around with vintage computers as it enables testing hunches fast and ruling stuff in/out without having to have a massive stock of spare chips, and even then not knowing if the one to be swapped-in is actually good or not. It can apparently even dump and program some ROMs!
  3. Barrymagrec

    Barrymagrec pfm Member

    I used to drive past there every day on my way to and from work - I used to sometimes wonder if the legendary Ray Dolby was inside thinking up some new must have for recording studios.
  4. MJS

    MJS Technical Tinkerer

    Back in the day I found a load of Dolby A decoders and manuals in the back of a cupboard at a post production facility. They must have been used on a telecine or some older VTRs. I too was surprised that they were made in Stockwell. Those were the days when everything could be bought from and made in the UK. Except of course for some Sony kit but even that came from a factory in Wales some of the time.
    Darmok likes this.
  5. Tony L

    Tony L Administrator


    Final batch of transistors arrived about an hour ago, I’ve flung them in, and it looks like it might even work! It gets through the self-test option in the menu system anyway! I just need to learn how the hell to use it now…
  6. Barrymagrec

    Barrymagrec pfm Member

    Looks very good Tony.
  7. Tony L

    Tony L Administrator

    Seems to work. I tested a few 4116 DRAM chips, some I knew were fine as they were NOS and I’d used 48k of that batch, and some really crusty ones where I knew at least one was problematic. It found a faulty one and cleared the known good easily enough. The 4116 is a pretty good one to test as it needs the 12V supply as well as +/-5V and it all seems fine powered from an Apple USB2 iPhone charger. I tested a couple of 74LS series logic chips too, and they tested ok. The menu interface is pretty clunky and time-consuming to navigate, but it works and does what I need it to do.

    PS Found it a flight-case:

  8. Darmok

    Darmok "In Lation, Trans Lost."

    ^^ :cool::cool: ^^
  9. PigletsDad

    PigletsDad My intelligence test came back negative.

    I see it has a USB interface. What does that do? Firmware updates?
  10. canonman

    canonman pfm Member

    I went there in the early 80's, quoting for PCB assembly work but they were too tight on price that they would pay:)
  11. Tony L

    Tony L Administrator

    That’s just the power input I decided to use (there are several options), there’s an Apple iPhone charger at the other end of the blue cable. The firmware can be updated, but it is way more complicated and you need to go in through the dual-row 6 pin header in the middle of the board. I bought it with the CPU installed and flashed so I’ve not dealt with this at all. There is only a beta later than what is on my board anyway. I’ll only think about it if anything really significant is added. It is a pretty mature product as is, every retro chip I can think of is already here. I doubt I’ll ever need to flash it unless I somehow hurt it.
  12. russel

    russel ./_dazed_and_confused

    Is that ESD compliant?, plastic/glass is not great for components. If not just put it in an ESD bag before boxing.
    Tony L likes this.
  13. Tony L

    Tony L Administrator

    It is a worry with all this open-board type stuff. That said modern single-board computers, which in effect this is, do seem fairly immune, e.g. I’m astonished how resilient say a Raspberry Pi or Arduino is just as a bare board floating around in any number of scenarios. The ATMega CPU is well tucked away under the raised display and from what I can make out is diode-protected from just about anything that could harm it in use, though how ESD safe it is I have no idea. I’m hoping the box is no more risky than say a typical plastic case on a Raspberry Pi. FWIW I always ground myself before touching it or any other computer board.
  14. Tony L

    Tony L Administrator


    I’m not convinced this will achieve anything, but I’ve stuck a layer of ESD-safe foam mat (the stuff you push DIL ICs etc into to store or ship them) on top of the card support I’d already made to better support the board in the case. The only electrical component that can possibly touch the plastic box is the USB power socket. The board itself stands on plastic stand-offs (which I assume are ESD safe as they are designed for computers). The foam mat will do no harm anyway!

    PS There is no room for an anti-static bag, I’d need a larger box there.

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