So, I bought a portable…

[imactheknife]

That board still looks pretty darn good all things considered. You might even be able to get away with leaving the Hybrid alone once recapped.

No disk icon is probably due to that Conner HDD holding up the SCSI bus. They have the sticky bumper issue, and the rubber seals on them can also melt too.

Yeah, that drive to dead i bet. Bumpers and seal were like liquid lol.. nasty.. what or how do i get a blue scsi in this unit? It has a weird cable. I dont want anything external if i can help it

 

[imactheknife]

So, here’s my SCSI2SD mounted in the portable. I have the SCSI adapter to interface between the Portable’s proprietary SCSI interface and the SCSI2SD. I also mounted it on some plastic standoffs to keep it away from the metal shielding underneath.

Where do you get the that adaptor? Looks like what I want to do for sure. The original hard drive seal and bumpers are liquid goo.. and

 

[3lectr1cPPC]

One of these ought to do it: https://androda.work/product/macintosh-portable-adapter-for-bluescsi-v2/

 

[3lectr1cPPC]

The lead-acid battery on the non-backlit Portable offered up to ten hours of usage time, and the Portable draws the same amount of power when turned off, and when in sleep mode.[2] Unlike later portable computers from Apple and other manufacturers, the battery is wired in-series with the AC power supply. There being no possible alternative direct connection to the AC supply, a dead battery meant that the computer could not be operated. The original power supply had very low output. Several popular unauthorized workarounds were devised, including using a power supply from the PowerBook 100 series, which provides higher output. As with automotive batteries, the sealed lead-acid cells used in the Portable failed if they were fully discharged. The batteries are no longer manufactured and it is very rare to find an original battery that will hold a charge and allow the computer to start. It is possible to repack the battery with new cells, or use alternative 6 V batteries.[3] There were three lead-acid cells inside the battery: each were manufactured by Gates Energy Products (now EnerSys), and they were also used in Quantum 1 battery packs for photographic flash use.[citation needed]

Someone should really correct Wikipedia here...

 

[imactheknife]

One of these ought to do it: https://androda.work/product/macintosh-portable-adapter-for-bluescsi-v2/

Cool, thanks! Ordered one. Will grab a memory upgrade when it becomes available too.

 

[desertrout]

Someone should really correct Wikipedia here...

Well, technically and historically it's true - people did (and still do) use 1xx adapters with Portables as an 'unauthorized workaround'... But I agree a caveat could be added here, noting that the machine was not designed to run from an AC adapter (rather the adapter was designed to charge the battery), and that there is a debate among Portable owners / experts about the damage that could occur from using an adapter other than one with the original specs.

 

[3lectr1cPPC]

I thought it was confirmed that damage WILL happen, just not immediately. Is there any debate remaining about this?

 

[desertrout]

LOL yeah sorry I guess there's still debate on this in the sense there's still debate about anthropogenic climate change... the actual experts overwhelmingly agree, but you still find folks out there who don't. At least I still see lots of comments online (not here) that using a 1xx adapter is just fine. So, I guess no real debate among experts afaik.

 

[360alaska]

Recently, I hooked one of my portables to a lab supply capable of giving 10 amps, it only pulled 1.6 amps. With that being said, it did have a battery in it, but the battery was somewhat depleted. Maybe I should try without and see what the current draw is.

 

[3lectr1cPPC]

At least I still see lots of comments online (not here) that using a 1xx adapter is just fine. So, I guess no real debate among experts afaik.

I'm pretty sure those people probably just haven't seen what experts say and have instead seen the bad advice. (just to be clear, I'm no expert either).

@360alaska - that would be an interesting test to see done.

 

[360alaska]

In theory it should be less, most of the power draw was to charge a discharged battery.

 

[360alaska]

I did some experimenting, and here's what I noticed:

When I used with a battery installed, it kicked off at 2A, but that dropped down to 1.5A pretty fast.

Without the battery? It started at 0.5A and quickly went down to 0.35A.

I've got a SCSI2SD inside. If you throw in a regular hard drive, you might see an extra 1-2A just when it's starting to spin. But the hard drive's official numbers are 250ma for 12v and 275ma for 5v. When you think about all the power changes, especially switching 7.5v to both 5v and 12v, it probably uses close to 0.75a in action.

So, my guess? The battery might've been necessary to give the hard drive a bit of a boost during its startup, even if it was plugged in.

It my also surprise you to know if you take the battery cover off and put a 9v in the 9v slot it will boot off of the 9v. This is probably another funny side effect of not needing the surge current for the hard drive.

 

[LaPorta]

The machine won't run without the battery (meaning just the power supply). However, cool trick as far as the 9V. I know that taking the cover off takes the main battery out of the circuit and uses the 9V to keep the RAM supplied. I guess it keeps the entire rest of the machine supplied as well.

 

[360alaska]

It will start, even with the original power supply, the problem is the power manager can get confused, resetting it helps. It's also easy to install a battery, boot and remove it, you can shut it down and as long as it doesn't loose power it will still boot so maybe a small cap across the battery terminals will help with this hiccup also.

 

[LaPorta]

Interesting....mine definitely does not do that. It won't do a thing without a battery.

 

[3lectr1cPPC]

I’ve seen conflicting reports like these before - some people saying their system won’t start at all with no battery and original AC, and other saying it works but is unstable, or tries to start and then dies, etc.

So to Alaska’s report - does this mean it’s safe to run with a 2A adapter and no battery? All I’ve heard before is that it will blow a mosfet after a while…I think it was the charging one? I don’t entirely remember.

 

[3lectr1cPPC]

Maybe @techknight could weigh in here.

 

[desertrout]

It my also surprise you to know if you take the battery cover off and put a 9v in the 9v slot it will boot off of the 9v. This is probably another funny side effect of not needing the surge current for the hard drive.

I know that taking the cover off takes the main battery out of the circuit and uses the 9V to keep the RAM supplied. I guess it keeps the entire rest of the machine supplied as well.

One my 'favourite' moments from Computer Chronicles is when the guy from Apple is demonstrating this very feature, forgets to put the battery cover back on, and the machine shuts off. Then he can't turn it back on again to continue the demo because the power manager needs to be reset... he soldiers on, but you can just tell he's sweating bullets the entire time. He never does get it to boot again, and they end up having to stitch in some footage in post to show the display Stewart asks to see more of. Poor guy, lol.

 

[desertrout]

So to Alaska’s report - does this mean it’s safe to run with a 2A adapter and no battery? All I’ve heard before is that it will blow a mosfet after a while…I think it was the charging one? I don’t entirely remember.

That's my understanding as well - not so much that the higher amperage damages chips, but that over time Q16 will burn itself open allowing 6V+ and worse (i.e. 7.8V) through to the PMGR etc. instead of the regulated 5.2V... but how exactly the mosfet fails in this circumstance is unclear to me.

 

[desertrout]

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