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Terminating cheapo SCA -> 50Pin SCSI adapters

Posted by: max1zzz on 2013-09-17 23:49:59 Yeah, it is really just the luck of the draw weather a drive requires extra termination. For ones that don't there is no need to add the extra 8 resistors. Using inline terminators was what i originally intended to to, however i decided just to see if i could just add the termination to the board. However i guess the real use of these is not so much for the termination, but to allow some more picky drives to be used

Posted by: Bunsen on 2013-09-18 09:25:50 Awesome work.

Posted by: max1zzz on 2013-09-18 17:10:55 Thanks 🙂 I shall be makeing a few of these if any members are interested, £4.50 + whatever the shipping is.

Posted by: max1zzz on 2013-09-21 03:43:35 finally got a working BD0366459B (first was bad, second i think got damaged in transit) i can confirm that terminating the extra lines made all the difference, without doing it the drive is not seen in anything but with it the drive works fine 😉

Posted by: Trash80toHP_Mini on 2013-09-21 08:39:44 Great R&D on the wide side termination issue, comrade. :approve:

Posted by: max1zzz on 2013-09-21 09:56:42 thanks 😉 Tbh it was less of research and more of just probing a dead hdd to find out how it was terminated, and then a little guesswork Hopefully this will allow a much wider range of drives to be used in these old macs, i'm planning to buy a random sample of whats on ebay and see which work

Posted by: Trash80toHP_Mini on 2013-09-21 10:31:34 That pretty much sums up the definition of R&D to me! 😉

Posted by: max1zzz on 2013-09-21 16:41:59 Your right there actually, I guess I can call it R&D then 🙂 Also, anyone else have a recommendation of a picky drive I should try next? If not I'll just grab the first sub £10 sca drive my next eBay search brings up (actually I did find a lot of 5 36gb sca's for a little over £20, very tempting...)

Posted by: max1zzz on 2013-09-25 08:08:05 Got a new drive today, and it has a interesting feature, it can be set to narrow or wide mode... in wide mode it needs the extra lines terminated, but in narrow mode it dosen't the drive is a 9.1gb 7k2 rpm compaq bb009135b4 (or a fujitsu mah3091mc - it is the same drive) i wonder if this is common on ultra 2 drives? (i must add i haven't tried it on a 68k yet, just on the g4 qs, but i don't see why it wouldn't work)

Posted by: uniserver on 2013-09-25 09:17:08 but i don't see why it wouldn't work) try it first. before you say this.

Posted by: Paralel on 2013-09-25 09:48:17 I have to disagree with you, Uni. There's no problem with forming a theory and sharing it. It's not as though he said it worked when he hadn't tested it. Hopefully he will test it and share the results. We're all here to learn, as well as help, one another; share knowledge, experience, and theory, no?

Posted by: max1zzz on 2013-09-25 10:03:25 yeah it works I do understand what uniserver said - these macs can be picky my assumption was because this drive had a setting to set weather the drive was on a narrow or wide bus they do seem to be much less picky with all the lines terminated though, i plan to continue testing random drives like this

Posted by: uniserver on 2013-09-25 10:24:27 Not trying to poke at anyone, Its just, this is not in the lounge, and wouldn't want a ton of people to flock to ebay and buy up hd's only for them to not work. thats all. For sure these terminating adaptors he is making are very awesome! They will save people time and money. and not to mention his solution is more compact/integrated then any other solution out there. There was a nice solution OWC was selling, but not any more. This solution is next best inline! So to conclude, For people that might come across this, There are some SCSI hard drives out there that will work good in Vintage Macs, (with this adaptor he is selling) We need to make a thread that has a standard format, with a photo of the Hard drive that works, then specifications of it. Maybe with current price per. Obviously cheaper is better 🙂 Great Availability is also pretty nice too 🙂 Also when in doubt, one could purchase a working scsi hd from me for $20 ea (ready-to-use)(will ship international) To be used with one of these fine #Terminated SCA adaptors#.

Posted by: Paralel on 2013-09-25 11:32:26 You make a good point, Uni. I guess there is a certain amount of duty to protect the greater public from themselves.

Posted by: max1zzz on 2013-09-25 12:13:42 I do agree with uni, that is why i did add that note, the only reason i didn't test it on a 68k first is because i had just got in from collage and didn't fancy waiting the half hour it can take my 450 to format a large hdd A list is a good idea, i would add that it might be a good idea to add weather a drive needs the extra lines terminated or not

Posted by: gsteemso on 2013-09-26 20:13:50 These things look awesome. Nice work! I’ll definitely keep this thread in mind for when the 1GiB drive in my Quadra 840AV inevitably dies for good. (It’s not doing well at all.)

Posted by: max1zzz on 2013-10-04 08:04:14 Got my latest drive, a 18.4GB compaq And it is not compatible, although it works in my G4 QS with a scsi 1 card it dose not work in 68k's Drive model number is:BD01864552 So there's one to avoid. will see if it works on the 8600's fast scsi bus. Also got my order of SCSI -> 50 pin adapters, just hopeing my reel of 0805 110R smd's is going to turn up in the next few days so i can get to work on these adapters...

Posted by: NJRoadfan on 2013-10-04 08:57:20 Was the 18.4GB formatted using Apple's Drive Setup under OS9? OS X doesn't install a Mac driver partition required for classic Mac OS.

Posted by: max1zzz on 2013-10-04 09:16:08 No, but i tried to format it using apple hd sc setup under 7.5 and it just wasn't seen I actually tried it on the 450 before the G4, and it still wasn't seen

Posted by: max1zzz on 2013-10-11 10:01:54 Well, SMD's really neaten things up, even if there a little tricky to solder (that nasty looking stuff round some of the resistors is just excess flux i haven't cleaned, should look a bit better once thats cleaned off)

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