tms@mtuxo.UUCP (01333-T.SLAIGHT) (02/05/88)
I don't know why you say that the MacSnap isn't suitable for such upgrades. I've used the MacSnap 548s to upgrade my 128-to-512 system to 2 MEG plus SCSI port. I upgraded my 128k Mac to 512k by the following method: 1. remove 64k chips 2. install 256k chips 3. Piggy-back a second multiplexer and resistor onto the board 4. Cut single trace After which, I had the ROM/DRIVE upgrade performed at my local dealer (Who thoughtfully overlooked my "512k" mod). Finally, (for now) I've installed the MacSnap 2 MEG upgrade, and SCSI port. Everything works fine. The only problem I had was that I had socketed the 256k chips when I first installed them, so the MacSnap wouldn't fit. The MacSnap will only fit correctly if the memory chips are soldered directly to the motherboard. Fortunately, I used "cheap" sockets so I was able to remove them fairly easily by pulling the plastic part of the socket away from the pins, after which the individual pins were easy to desolder. (Of course, you need a good solder-sucker and iron, plus some desoldering experience). If you have the "high quality" pin type sockets, which some third-party upgrade installers boasted about using in their upgrading, they'll be harder to remove. The only techniques I know for removing these involve nibbling away the plastic using a sharp pair of dikes until the pins are exposed, and then desoldering the pins. If you're 512k "upgrade" is already soldered in, then there shouldn't be any problem. Note that my motherboard is a "first production" version 128k. Most 128k's were built with later boards. So if the MacSnap fits in my "early" board, and also fits in "genuine" 512E's, it should fit in all 128's inbetween. I haven't tried the SCSI port yet, but I have high expectations that it will work. --- Tom Slaight <Disclaimer: Opinions expressed are my own.>