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Do you have an oscilloscope? I would measure this point in the circuit and see if the amplitude declines. You might be able to catch this with a voltmeter in peak measurement mode which you reset between playing a sound. Basically, if the voltage levels declines (when you play the beep sound in...

If you want to further narrow down the location of the sound issues, put some headphones on or use an external speaker. If the problem persists, it exists prior to that portion of the sound circuit.

Well, it was a team effort. You were passionate about getting the issue attention to be fixed, and @SuperSVGA found and analyzed the faulty code. The more I use the Portable, the more I fall in love with it. It has a really smooth keyboard and crisp screen. Now we just need to get the SLIMs...

Very nice!

Based on the work of @SuperSVGA and @JDW, I created a system extension that quiets the 10 second popping. You can use this with either the backlit or non-backlit Portable, on any system version that the Portable supports, with any version of the Portable control panel. Use StuffIt, BinHex, or...

Ahh! That answers that question. Thank you.

As I have been looking at the Macintosh Portable in more depth. I've run across a couple of pieces of technical information that may be valuable to other developers. PRAM The original Macintosh computers (128, 512) had 20 bytes of PRAM (parameter RAM). This battery-preserved memory stored a...

That's good news. At least it isn't a hardware issue.

I do use the Desktop Mgr extension (to not have the desktop rebuilt when switching between 6 and 7). I don't think that is a cause. But, who knows.

I reduced my system down to a floppy disk and verified that it sleeps when booted from a FloppyEMU. The .dsk is attached. It is not actually a .hex. I added that to allow it upload to the forum page. Download and just rename it without the .hex at the end.

I am rewatching your video to see if there is something obviously different about yours.

ZuluSCSI Compact RP2040 Lead acid. Battery 50-60% full based on battery desk accessory. No modem installed. October 2023 Androda Portable RAM card 5 MB (no jumper lead or special option). So, 5 MB total (1MB motherboard + 4 MB card). Finder running only (not Multifinder) Backlight...

I can confirm the same. Backlit Portable, PowerBook 7.1 control panel, AppleTalk off, power adapter unplugged, maximum conservation. Sleep in about a minute. Weird. On the same machine as above, but booting into 6.0.8. With Portable v1.2 or 1.3, the machine will go to sleep after 1 minute. So...

In System 7.0.1 the patch is located in the System file at 'lpch' #8 @$1206. In System 7.1, the patch is located in the System file at 'lpch' #8 @$11b4. I believe a long-term solution is to write a new init that removes the ROM and/or patch VBL task and replaces it with a custom one from us...

The Macintosh Portable has a certain cachet. It possesses an exquisite keyboard, a crisp screen, and a complete set of ports and slots. Unfortunately, the size, weight, and price were derided at the time of launch. Presently, the challenges of a Portable are: 1. Most cases are cracked due to...

There are a number of modern battery holder choices available to the vintage hobbyist. Someone even recreated the Apple holder: https://www.ebay.com/itm/177348885387?itmmeta=01KF2SFJTSA86H7PVA347YHAFK&hash=item294ad13b8b I tend to solder the standard battery holders directly to the...

Here are more details: https://tinkerdifferent.com/threads/macintosh-ii-iix-battery-holder-daughterboard-analysis.4978/

The Macintosh II and Macintosh IIx originally had soldered-on batteries for retaining parameter RAM memory and the clock. Later versions of the Macintosh II motherboard and all versions of the IIx motherboard had holes and spacing to accept batteries holders directly. (You can use these holes...

Your comment was thought provoking. So, I just did an investigation and measured it. The problem with that capacitor is that it is wired across both batteries, but only one battery powers the PRAM/clock chip. If you replace each battery individually (leaving the other battery in place), then...

I picked up what I thought was the low-power + EMI filter Portable (or PowerBook) mouse. Indeed, it has the extra long connector. The inductance of the cable wires are 1.8 uH on the standard cable and 2.8 uH on the longer connector. However, upon opening the mouse, I discovered that the...