Upgrading And Desoldering A Fake CPU

[quarterturn] had an old Apple Powerbook 520c sitting around in his junk bin. For the time, it was a great computer but in a more modern light, it could use an upgrade. It can’t run BSD, either: you need an FPU for that, and the 520 used the low-cost, FPU-less version of the 68040 as its main processor. You can buy versions of the 68040 with FPUs direct from China, which means turning this old Powerbook into a BSD powerhouse is just a matter of desoldering and upgrading the CPU. That’s exactly what [quarterturn] did, with an unexpected but not surprising setback.

The motherboard for the Powerbook 500 series was cleverly designed, with daughter cards for the CPU itself and RAM upgrades. After pulling the CPU daughter card from his laptop, [quarterturn] faced his nemesis: a 180-pin QFP 68LC040. Removing the CPU was handled relatively easily by liberal application of ChipQuik. A few quick hits with solder braid and some flux cleaned everything up, and the daughter card was ready for a new CPU.

The new FPU-equipped CPU arrived from China, and after some very careful inspection, soldering, and testing, [quarterturn] had a new CPU for his Powerbook. Once the Powerbook was back up and running, there was a slight problem. The chip was fake. Even though the new CPU was labeled as a 68040, it didn’t have an FPU. People will counterfeit anything, including processors from the early 90s. This means no FPU, no BSD, and [quarterturn] is effectively back to square one.

That doesn’t mean this exercise was a complete loss. [quarterturn] did learn a few things from this experience. You can, in fact, desolder a dense QFP with ChipQuik, and you can solder the same chip with a regular soldering iron. Networking across 20 years of the Macintosh operating system is a mess, and caveat emptor doesn’t translate into Mandarin.

54 thoughts on “Upgrading And Desoldering A Fake CPU

  1. Ahh, the 68LC040! The first laptop I ever owned was a Macintosh Powerbook 190CS, which I got on the cheap as one of my first ever eBay purchases (yes, that means I got it when it was a few, if not several, years old… though eBay was also very young at the time). I remember being extremely depressed when I found out that the lack of the FPU meant that it would never be capable of playing MP3s (back when a 128kbps CBR MP3 was considered “Hi-Fi” for music on your computer), and I believe that might also have been what prevented me from being able to install BeOS on it.

    I did end up getting a cheesy Mac-compatible IRC client installed on it so I could “socially network” from the comfort of my bed, though.

    1. I’m a bit surprised having no FPU is such an issue. Doesn’t BSD have an FPU emulator?

      For MP3s there are integer only implementations like libmad and there is a hand tuned 68k decoder by Stéphane Tavenard.

    1. While I’m all for hot air, these QFPs can be very large, with an area often bigger than 1 square inch. You’ll often need a special nozzle to get the hot air applied correctly.

      1. Well, if you don’t mind reusing the qfp you’re desoldering you can cut off the legs from the chip and then remove them one by one easily.
        As for bga, you simple can’t use the soldering efficiently on them.

        1. Doing this you can easily damage the pads and traces of the PCB. I prefer a powerful hot air gun. Of course its a good idea to shield surrounding components with Kapton or Al-foil.

      2. Assuming you don’t mind destroying the chip:
        Blast the middle of the chip with the hottest setting your air rework station will go using a nozzle that is smaller than the body of the chip. This will quickly crack the hell out of the chip from thermal stress. After a little time, the heat will flow out of the package and desolder all the pins and you can just lift it up.

    2. If it only had parts on one side then I would say yes, have at it with the hot air rework station. But in the case of the daughtercard, there’s a large FPGA directly behind the CPU. I didn’t want to risk screwing that up.
      Looking back on how it went, I would say the absolutely easiest way to do it is to preheat the whole board, and then use chipquik on just the CPU with a regular iron. This is what I did, but I didn’t get the board very hot as I just heated it over a lamp.
      If I can score a source of legit 68040s, I will definitely do it on the preheat area of the rework station.

  2. Which came first, the 68LC040 or the 486SX? Apple did some odd things with the gestalt ID. For example, if you overclock an LCIII from 25 to 33 Mhz and change nothing else in hardware or software, the System will automatically change About this Mac to say it’s an LCIII+. If you install a DayStar Turbo 601 PowerPC 601 upgrade card into a IIci, it gets identified as a “Powermac 475” due to the Turbo 601 for the IIci, IIvx and IIvi being based on the 601 upgrade for the LC 475.

    Mac OS 7.6 supposedly does not support 24 bit addressing mode, but when I had a IIci with a Turbo 601, I noticed that when switching off the CPU upgrade and rebooting to use the 68030 that the Memory control panel would have a 24/32 bit mode switch appear. I don’t recall now the exact method to get it to show up, I never tried running any software on it that required 24 bit mode. I just clicked it to 32bit and rebooted. The switch would then vanish from the control panel.

    1. from: https://lists.freebsd.org/pipermail/freebsd-hackers/2007-March/019902.html
      > First, FPU emulation is rather slow, and second, someone
      > would have to write the code. In the past, the FreeBSD
      > kernel had two FPU emulation libraries (for emulation
      > of FPU instructions in userland). One was BSD-licensed,
      > but incomplete and not 100% compatible, and the second
      > was GPL, so it couldn’t be enabled by default. As far as
      > I know, both of them were removed because hardware without
      > an FPU was considered obsolete, and nobody was willing to
      > improve and maintain the code.

    1. If you’re really going to ask why someone would do something, why read Hackaday? You do it because you want to and because you can. It’s the same reason I want to upgrade to a Pentium M 1.1Ghz chip on my old Asus Eee PC. Not to mention that having the full Pentium chip vs the Celery will help with basic graphical tasks.

  3. Did you order it from the ‘hkutsource’ Aliexpress store? Aliexpress comes with free escrow. You have 30 days to declare it fake and open a dispute. Alibaba has a new team dealing with fakers. You’ll likely get a full refund and the store will get shut down. Of course if you don’t start the dispute, nothing is going to happen.

    A general tip – if the price is out of line with everyone else offering the same product, something is up. Don’t buy from a place like that. I’ve made hundreds of Aliexpress orders with about a 2% problem rate. I have not received anything fake, but I have received the wrong items. There is no pattern to these wrong shipments, sometimes the item is worth more, sometimes less. I think they are just mistakes. I get the wrong stuff from Digikey occasionally too.

    Also be vary when buying clones of common chips. These clones will be similar, but not exact replicas. You need to use the datasheet for the clone, not the datasheet from the original. The vendors are not hiding the fact that these chips are clones, the ones I have seen have different markings on them than the originals.

    1. Are you required to send the fake item back for this, or photographical evidence of counterfeit would suffice? Sending stuff back to the Far East very often exceeds the items cost so it’s not pratical for most people.

      I also have no problems with copies of chips when they work as advertised, especially old no longer produced parts, in that case piracy is a godsend. What I’m angry about is the mislabeling of lower specced chips or worse, like say labeling a 555 as an ultra low noise intrumentation opamp.

      I believe I’m not the only one who would happily pay a subscription for a service that randomly and anonymously buys chips from China then reveals the fakes.

      1. I’ve never had to send anything back. The only time I had pushback was a seller insisting they sent an item with and order, but photos of the packaging (which have weight stamped on it) and a scale showed it to be too light to include the missing item which thankfully was much heavier

      2. It varies whether Aliexpress wants the item back. Sometimes they want the item back as evidence that the store is shipping fakes. But in my experience fakes are rare and if you exercise some common sense they can be avoided. ie don’t buy from the vendor that 50% less than 15 other vendors offering the same item.

        Counterfeits are a completely different issue. Both you and the vendor know the item is counterfeit. It is the company being counterfeited that is doing the complaining so that they can charge high prices for the same item. This is a thorny area since the IP laws in many countries excessively favor the IP holder over the general public,

        1. In MY experience, buying a Motorola part that looks like that from a Chinese source, almost guarantees it’s a counterfeit/remark/fake. Parts brokers are notorious for sourcing fake parts.

          Top of package looks damaged
          Leads not remotely coplanar

          The part has either been desoldered or has rattled around long enough that I wouldn’t buy it at any price.

          1. Yup, remarked 68060’s from China have long been a problem in the Amiga and Atari communities.
            They mostly take old XC or EC chips and mark them as full parts, sometimes even at speed ratings that Motorola never made !

    2. This was off ebay. Unfortunately I initially thought I was getting misinformed by 7.1.1 due to an enabler, and I figured who the hell would fake a 68040, so I closed the transaction. It was only about $15 plus shipping. The only other option at the time was a total nutcase wanting $150 per CPU. Screw that!
      I was actually more concerned with the crummy condition of the chip. It was pretty oxidized and had bent pins. And it’s probably not so bad that it’s an actual working 68lc040 vs some generic FPGA with the same footprint.

      My next order, if I do one, will probably be aliexpress, and for sure if THAT turns out to be fake I will put the hammer down on the seller.

    3. Aliexpress comes with free escrow. You have 30 days to declare it fake and open a dispute.

      With aliexpress you can open a dispute and get a full refund for a fake i it’s specifically sold under “Guaranteed Genuine” protection (most aren’t) otherwise you must return the item for a full refund or negotiate a partial refund with the seller. If you can’t arrive at an agreement and need to escalate the issue with aliexpress, then good luck and be sure that the refund is worth the waste of your time.

      Even then, depending of the item, for a fake sold under “Guaranteed Genuine” protection you can get just a 15% refund for batteries or 9% for cables! http://www.aliexpress.com/buyerprotection/how_to_be_eligible.html

      As much as I dislike Paypal, they are much better for the buyer in that respect unless you are unlucky.

      1. turn out it is not fake just the wrong CPU. MC68040EC33V does not have an FPU, despite no LC designation! The original web page describing the upgrade was incorrect. MC68040FE33A is what I should have bought, and have in fact now ordered.

  4. only performance tests will tell you if it is real.

    if it truely has no fpu and no bsd then the software should crash especial software that does not first check and just goes ahead and sends fpu and bsd commands and the chip cant understand.

    there is a possible chance to avoid customs from keeping the package the chinese writes the text “no fpu” to the onboard rom so that customs will go “oh ok it isnt a true counterfeit” and let it go through.

    1. Hold on….
      Why would customs go checking the onboard ROM for anything? That would take some specialized equipment and I would be pissed if they fry my newly acquired CPU because some dope used the wrong socket.

  5. I remember running an old version of debian on a powerbook 145B (68030), and then thinking it was time for OS 7.5.3 again…

    Emulating the system on a modern system is easy, but new legal rules may make it illegal in the US even if you own the original hardware =(

  6. First, I have to say that I’m very upset with eBay because they don’t do anything when a chip seller sends counterfeit chips. I’ve had this happen three times so far, and while each time I’ve gotten my money back, I’d rather see the seller get kicked off because they’re committing FRAUD.

    The reason that working around the lack of an FPU is an issue is that many LC040s have a bug in the trap handling that causes an FPU trap to fail sometimes. FPU emulation works fine on m68020, m68030 and m68060 systems.

    The correct solution is to compile the whole OS without FPU instructions. We’ll have to get that fixed and binary sets for LC040 systems uploaded somewhere.

    1. eBay (as well as Amazon) suck and have sucked for a very long time. Many sellers are fair but they are swamped by sellers peddling counterfit wares, incorrect descriptions, and insane shipping prices ($2.93 for the bid. $12.95 for shipping. $5 extra if you want padding).

      Worse, their rules and site design favors high volume sellers rather than buyers or small sellers. Sometimes it’s so hard to filter out crap or counterfits on those sites, I’ll hit up a B&M and pay the premium for the real deal than run through the risk and hassle of buying, assessing, and returning.

      I also started going through specialty sites to buy my stuff. I pay a slight premium but I discovered many sites crack down hard on the stuff eBay/Amazon refuse to deal with properly. I ordered some collectable stuff available on eBay/Amazon from one such site. The stuff arrived but was clearly counterfit and not the real deal as was described (and premium paid). The site refunded my money, paid for shipping to their fraud department, counterfit confirmed, and the seller account was closed down within a matter of days. See that happen on eBay.

  7. “the Powerbook 500 series was cleverly designed, with daughter cards for the CPU itself”

    Clever perhaps, but not good. The 500 series was famously unreliable, and the extra sets of connectors to the mother board was a significant reason why.

    1. I’ve got the Freescale MC68040FE33A installed. And yet… it’s still not showing up as a full 68040 with an FPU. The datasheet says it has one: http://www.nxp.com/webap/search.partparamdetail.framework?PART_NUMBER=MC68040FE33A

      So yeah… no idea what the problem is and I’ve exceeded my patience with it. Is my MC68040FE33A fake? Is there some hidden errata that says “xxxx stepping does not contain FPU”? Does the ROM for the Powerbook somehow block using the FPU? I emailed NXP/Freescale support about the FPU, but it’s such an old part I don’t have my hopes up. Plus, I don’t think the Powerbook can take any more case opening cycles – the plastic screw pillars are all cracking.

      On the positive side, I’m now pretty good at soldering a big QFP! Using a Wolfvision viewer as a microscope, it’s really quite easy. Tack the corners, drag solder the sides, then clean up with solder wick.

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