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Thanks for the schematic!
Yesterday I spent a few minutes with it, I ran MacTest Portable again without the modem card installed and it passed the logic board test.
The modem board hasn't been recapped, and I don't really need it.
But even when it passes all of the tests (with the power...
Usually the logic boards need new capacitors, the main problems are weak audio, no video or strange things when connected to power, all of them can be solved with new capacitors
As for the hard drives, they can be repaired easily, I made a brief video showing how to fix them
Yesterday I turned it on and it decided to behave erraticaly again.
Just for fun I ran a copy of MacTest Portable and it reports a problem with the Power Manager. It suggests replacing the logic board and that's it.
Does anybody have a schematic of the power manager IC or at least a pinout?
Progress has been made:
I swapped the 2N5064 SCR with an original E0102 from my working Macintosh Plus ED, the Mac 128k started working perfectly!
So I guess the 2N5064 is more sensitive than the original E0102.
What is a good replacement for the E0102? (or the other similar ones found on...
I do have a first generarition Flir ONE (I took the photos at the Analog Board), the resolution is not that high (something like 80x60), but it uses a regular (VGA resolution) camera to increase the quality by blending the two images, this is the main difference between the Flir and the Seek camera
The Flir One thermal camera is one of the most useful tools I've bough. It is great for troubleshooting Apple logic boards (the new ones).
If you have a shorted power rail on a MacBook you stick some voltage on it and with the thermal camera you immediately see where the damaged component is...
There is a transistor on the "video board", (the one that connects to the back of the CRT), you should replace it, should be a 2N3906 by memory.
I also had a gassed CRT and after replacing it it did, the same thing, replacing that transistor fixed the problem
I might be wrong, but this adapter converts DVI to VGA, not the other way around since it is an "active" adapter. DVI-D only contains digital signals.
DVI and VGA are quite different (one is a digital interface, the other is analog), sometimes it's easy to obtain VGA from DVI because the analog...
On the analog side, Most of the primary was blown (shorted transistors and open/drifted resistors) also found a shorted capacitor!
I have replaced all of the parts except the SCR, which should arrive next week.
I also noticed that the "international" boards are far more rugged that the US...
Well, downgrading it is easier than expected.
Here's what I've done:
Remove all of the non-original modifications (jumper wires and piggybacked chips)
Install the missing resistors on RP3
Install a resistor on R4
There are no cut traces to repair
At this point, the machine would produce a...
Hello!, and thanks to 360alaska for sharing the files!
I gave the Macintosh Portable foot STL file to a local 3D printing company, and after a few modifications they were able to print it using a flexible TPU filament. the quality is not perfect, but it fits nicely in the portable.
They also...
Maybe my portable is not that sick after all.
I measured the battery voltage directly at the connector on the logic board and it was around 5.9V - 6V, Which the portable should correctly report as "low". (5.8V should be the cutoff voltage)
I connected my bench power supply directly to the...
Progress!
I Fixed a bad connection on C15 and now the portable boot up every time from the hard drive even when powered only by the battery. I can also use and eject floppy drives, copy its contents to the hard drive and the portable never crashes.
The only problem that now remains is the...
Maybe that opamp is not a follower afterall...
What is C15 supposed to do?
I also found out that the to 5V rails (tabs on Q16 and Q20) lower in voltage when both battery and PSU are connected.
The voltages shown in my posts above are measured at pin 52.
I can confirm that the signal comes from the hybrid (from the last pin, the one close to C15), goes thru a low pass RC filter and then ends at pin 52 of the PMU. I could not find a capacitor near the hybrid.
within the hybrid, the...
I would try disconnecting the battery first, then the hard drive.
Also, the display panel also contains capacitor that are prone to failing, you loose contrast and you may get some flicker.
I'm back!
Today I decided to bring the beast back onto my workbench. So far I fixed the squeaking noise from the speaker by cleaning the board again and swapped the mechanics of the hard drive with another one with a good gasket (the models with a green label seem in better shape than the ones...
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