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Hi, it's relatively simple: - You need a load, in this case power resistors. I had a box with a few of them and tried different combinations to get curve points for different loads (the lower the resistance, the more current will flow). - You want an ammeter in series with the load to measure...

I would recommend replacing the hybrid as well, even as a preventive measure. Bad hybrid might send >6V to the AD converter of the Power Manager chip, which fries it (and the only source is another Portable or PB100). Based on my M5120 with two units, I suspect hybrid modules are actually the...

The green light likely means that the breakout board in the rear is getting power (+5V) from the main board. Unfortunately, this doesn't prove whether the card is actually communicating on the PDS bus.

Surprisingly, older generation of optical mouse sensors (used in optical Logitech mice for example) also outputted quadrature signals directly. I described the conversion on my website: https://dymczyk.com/diy-macintosh-128k512kplus-mouse-from-an-e-waste-container

Cool. And I realized I wasn't very clear: the pin numbers I mentioned are on the IDC connector so you would need to take into account how this turned socket is wired into the IDC plug.

@mg.man it looks very much like it could be compatible - the big IC in the DIP48 package is likely DP8390, the same as on the Kinetics I tested MacTwister with. (and also MacCon uses the same family) Any chance you could check how AM7992B is wired to the 16pin connector? (I assume it's J1)...

Yes, exactly, it is marked as "low power". In my case (but obviously it depends on the history of use and the storage conditions), it was the one in the worst condition of all three. I did this recap a while ago and honestly I didn't take detailed pictures of the caps. I have a few overall...

Online, you can find a lot of discussions related to what power brick to use with Macintosh Portable (the original is M5136 7.5V 1.5A), if it has to be exactly 1.5A or can be more and if it’s worth recapping the power supplies. I decided to at least somehow help in those discussions with...

Yes, totally, that would be possible! For now I really focus on an MVP to get the project out :) Oh, interesting. Dayna E/SI (like this one https://www.worthpoint.com/worthopedia/daynaport-ethernet-card-apple-1996392707) uses a 16-pin IDC connector which I'm pretty convinced is compatible (the...

Hello, I would like to share my project that is long overdue for publishing here - MacTwister, a fairly universal Twisted Pair breakout board for a variety of SE and SE/30 network cards. It’s about the small PCB that you screw to the computer chassis that contains an external connector. I was...

I happen to own three Macintosh Portables and I was looking for a way to charge their batteries every now and then, without unpacking the computers from their safe storage. In short, I needed an external charger for Mac Portable batteries. Today, I would like to share my design of a 3d-printed...

I can only say that one of the two PB100 boards I have has exactly the same fix. To me that rather looks like a factory-done fix of the suboptimal design, probably with either stability or EMC immunity/emission problems.

I had the same problem when I disassembled my PB100 (someone was there before and tear off the contacts) and I ended up getting this one: https://www.aliexpress.com/item/33039490153.html?spm=a2g0o.order_list.order_list_main.252.39041802LXlLaC (it works)

I sourced some genuine one from local auction sites with NOS chips. Alternatively the ones from China (Ali/eBay) even though potentially remarked, work pretty reliably and cool for me :)

That might be the analog board, but I have seen identical lines on an SE/30 with a broken ICs in the UE8/UF8/UG8 row (those 3 specifically were in a particularly bad shape). I just replaced them all and the computer is reliably happy.

You can and actually you should - I saw some Portable/early PB adapters with a very unstable voltage and very leaky caps. The only tricky part is cracking it open, I used the "vice+pencils" method which was described somewhere here.

Are you sure it's actually spinning? I had a very similar Quantum drive in my hands and the grease solidified to a point where the disk would not spin on its own. Unscrewing the PCB and a cover below it let me "help" the drive to spin the platters with my fingers and boom - a clean boot straight...

@my03 thanks a lot for reporting back! I happen to work on getting an old MacCon to work right now and I have trouble with a connector card it seems. It works fine with the AUI (and an external AUI->RJ45 converter), but doesn't negotiate with my modern router with the onboard connector. Could...

For me the behavior was similar because the address line was shorted to ground. The ROM could not be accessed properly and the system was stuck in a reboot loop. As far as I remember, it's the PMGR that controls the SYS_RST line so it could very well be that there's something wonky about the...

Good point! Also based on @techknight advice it's important to power both positive pins in the 4-pin Molex if you haven't done so, otherwise something might get fried.