BlueSCSI on Macintosh Portable

Sideburn

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Jun 16, 2023
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My test was done with the power supply connected (no way the battery I have can last 7 hours!)

I have a 6V 5Ah Lead Acid: https://www.amazon.com/gp/product/B00MYL8OQU/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Got some copper sheet and made a 3d printed repro :)

I get 7 hours just running the After Dark screensaver all day as a test. And thats skipping through all of the battery low warnings til it finally shuts down.


70771980791__EE88625A-E659-4A7C-BCA1-9D889993914B.jpeg
70771971534__5FC16BE6-04FF-48AC-9BF3-88C0C012C3C2.jpeg
 

Sideburn

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Heres some speed test results before sleep and after using Speedometer 3.23 (not sure what units those numbers are in but quite a difference):

1.252 before sleep.
0.551 after sleep.

So after sleep the CPU is running at about 50%

before_sleep.jpeg
after_sleep.jpeg
 

Paolo B

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Nov 27, 2021
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Nagoya, Japan
I have a 6V 5Ah Lead Acid
I rebuilt a couple of Portable batteries over the years. By rebuilding I mean pry open the battery case, replace the cells, seal back the case.
At first, I used the same cells as the original ones. Perfect result, but same issue as the original ones. Once they discharge below a certain level, they are dead. I then used a Panasonic LC-R064R5P unit. Only 4.5 Ah, though, so it won’t last much without the external power supply.
The unit with the Panasonic cell is at least 10 years old now and it‘s still working fine.
If it discharges completely, it takes a few hours before I can start the Mac, but other than that it‘s OK.
 

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Sideburn

Tinkerer
Jun 16, 2023
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82
28
California
youtube.com
I rebuilt a couple of Portable batteries over the years. By rebuilding I mean pry open the battery case, replace the cells, seal back the case.
At first, I used the same cells as the original ones. Perfect result, but same issue as the original ones. Once they discharge below a certain level, they are dead. I then used a Panasonic LC-R064R5P unit. Only 4.5 Ah, though, so it won’t last much without the external power supply.
The unit with the Panasonic cell is at least 10 years old now and it‘s still working fine.
If it discharges completely, it takes a few hours before I can start the Mac, but other than that it‘s OK.
Oh wow I didn’t realize you can’t fully discharge the lead acids. Yikes I probably came close a couple times when I was testing it.
 
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Paolo B

Tinkerer
Nov 27, 2021
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Nagoya, Japan
I did some tests and I confirm I cannot reproduce the pattern you see (before/after sleep).
Before / after has no impact and for some reasons I also get better scores than you get.

Before Sleep.png
After Sleep.png
 

Sideburn

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I suspect your machine is trying to balance performance and battery life. I have "max performance" as default setting.
I found the culprit! It's the 7MB RAM expansion.

I pulled the card out and bam! my machine was running at full speed (even faster than yours at 2.154) before and after sleep.

Both issues fixed with RAM card removed.

IMG_5385.jpeg
 

Sideburn

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So to sum up this thread:

• BlueSCSI needs external power from floppy cable in order to wake it up after sleep.
• RAM expansion cuts CPU speed in half and then chops that speed in half again after sleep.

* could still be isolated case to a defect in my board. Won’t know for sure until someone else can confirm.
 
Last edited:
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alxlab

Active Tinkerer
Sep 23, 2021
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Well, I'll be taking a look at this to hopefully duplicate and try to fix.
I'll test out Speedometer results on my Macintosh Portable with the 7MB card installed tonight as well.

If it is an issue hopefully it can be fixed with a firmware update of the FPGA.
 

alxlab

Active Tinkerer
Sep 23, 2021
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Mac OS 6.0.8 with my old 3MB card
IMG_20230705_002505.jpg


After sleep:

IMG_20230705_002744.jpg



Hmmm maybe the psram on 7MB is being set into a low power/low performance state during sleep and doesn't recover.