New Member, Old Mac SE

[LazarusNine]

Since then I'm "obsessed" with networking Mac's.

Yeah, this is pretty much me as well.

Anyway, jefframsey, welcome to the forums. It's always nice to see others expanding the hobby. I won't repeat what others have said, but simply echo their suggestions to make cleaning the board a top priority. Simply wiping affected areas with a swab and cleaning solution may not be enough. You need something to neutralise the battery leakage, and I'd actually stick that entire board into the dishwasher once all the removable components are extracted. Alternatively, a bucket of water with a bit of washing up liquid will do the trick. Spend some time with a toothbrush and/or paintbrush working around all the nooks and crannies. Then get that board drying for *days* using whatever method you like. That should help clear things up enough so you know what you're dealing with.

I would then consider taking a look around the battery compartment and see what areas have been affected by the leakage. You gotta hope traces and vias haven't been rotted through. Moving outside of my particularly skill set, it is likely advisable to get a voltage meter out to see what (if any) traces have gone bad. It's worth recapping the entire board as well.

Compared to some of the others on these forums, I still consider myself to be quite an amateur at this stuff. However, the things I've described above represent some of the tricks I've learned from this forum (and others) over the years that have definitely helped me out quite a lot. Best of luck with this new project and I look forward to hearing how things turn out for you.

 

[hunter44102]

The cap looks to me like a 0.1uF 50v based on a Google of 'macintosh se logic board close up' and they had the yellow ones with a 104 marking.

What are the colors on the ones you have?

 

[jefframsey]

The cap looks to me like a 0.1uF 50v based on a Google of 'macintosh se logic board close up' and they had the yellow ones with a 104 marking.

What are the colors on the ones you have?

The are orange on the ends and brownish-grey in the middle. Would they be the same as the yellow ones in your picture? Mine looks exactly like the C10s in these pictures:
http://www.ccadams.org/se/SE-800k-logic.jpg

https://upload.wikimedia.org/wikipedia/commons/6/65/Apple_Macintosh_SE_Main_PCB.jpg

 

[hunter44102]

I saw another close up with the same ones you have and some had a 104 written on them.

we used to use these in electronics. They were almost always 0.1uF and are called 'decoupling' capacitors used for every chip to keep noise down

You would be safe to use that value. 0.1uf 50v axial.

 

[techknight]

yep, 100nF capacitors are used to decouple the power supply. the inrush of current required to overcome the capacitance of the bus to switch the state between 0 -> 1 and vice-versa requires a "storage tank" capacitor directly coupled with it to supply the current. Otherwise the switching spikes would end up on the rails and back in the power supply. aka... noise!  

The power supply itself and its rails/traces cannot because of the parasitic inductances. But at certain frequencies the capacitor acts like it doesnt exist so thats why you so commonly see them coupled together as a 0.1uf and 10uf electrolytic. 

 

[jefframsey]

So should I order 100 of the yellow axial 0.1uf 50v caps from eBay for $5.00? I'm bound to need more than one, right?

 

[techknight]

As long as they are from a known reputable manufacturer. There are alot of chinese fakes out there and they either dont last, or come new already shorted. 

 

[jefframsey]

They sell new 1/2AA battery holders for cheap if you want to replace

from China $1.55 including ship

http://www.ebay.com/itm/5-x-1-2AA-14250-Battery-Storage-Box-Case-Holder-3-6V-With-Pin-PCB-Solder-Lead-L-/401195657515?hash=item5d691fe92b:g:t~gAAOSwgQ9VzFqr

from USA $4.50:

http://www.ebay.com/itm/1-2-AA-Battery-holder-with-pins-for-slot-machines-/182460067953?hash=item2a7b77b071:g:w3MAAOSwnHZYjj4i

These battery holders look like they have a sprIng on the negative end. Would that make them too long for the spot on the board? Or do I mount it somewhere off the board and use a pair of wires to connect it back to the box?

 

[hunter44102]

The board looks like it has room even if longer, but I emailed the seller to ask for the pin to pin length to see if it would drop into the holes for soldering.

Below is one that may be shorter.   The existing one I measured to be 1.25" or (3.175cm)

http://www.mouser.com/ProductDetail/Keystone-Electronics/2103/?qs=2eeJ4RqLicEFfvqDKkW3gQ%3D%3D&gclid=CjwKEAjw8OLGBRCklJalqKHzjQ0SJACP4BHr9E1B88qRK1Ost0A1Ntt3DVHDgfcO2bRkIWOSuNmRTxoCz-Lw_wcB

https://www.amazon.com/KEYSTONE-2103-BATTERY-HOLDER-2AA/dp/B00DK871BK/ref=sr_1_2?ie=UTF8&qid=1490605993&sr=8-2&keywords=1%2F2+aa+battery+holder

 

[jefframsey]

I ordered the one from Mouser, and I ordered the capacitors from the too. Kemet brand, 0.1uf, 50V axial.

 

[Compgeke]

This here's a bit hacky but I've had success using a CR2032 holder on some leads. Completely wrap the thing in electrical tape in case of any potential leaks\shorts then tuck it away to the side. 2032s don't last 20 years like a black Varta, maybe 5 years or so at most but they're a lot cheaper and don't tend to leak as often.

 

[jefframsey]

New components will arrive in the mail Thursday. I just reinstalled the logic board following its second ammonia and water bath. After the first scrubbing, it still looked a bit dingy around where the battery had leaked. So this time, I heat d up the water a bit, soaked the board in it for 30 minutes, scrubbed again with toothbrush and then hung for two days to dry.

When I booted it up, I was greeted by a full startup chime! It has not done that since I first took the battery out. This time it sounded just like it should. I tried to run the SCHD tool and it still didn't find the quantum 40s. So I plugged in the original drive, the Miniscribe 20mb, and while it would not initialize, it did detect something was there, as it gave me an error saying that the system could not read the device that is connected to the scsi port. So it knew something was there.

Anyhow, when I get the battery and the capacitor replaced, I'll finish working on the drive and then go from there.

This is getting exciting!

 

[techknight]

At least the logic board is coming around! thats the majority of the battle! 

 

[jefframsey]

Last night, my cousin (who is much better at soldering than I am) stopped by and helped me get the new capacitor and battery holder installed. We had to file down the posts on the battery holder to get them to fit the holes in the logic board. Here are a few pictures of the installation.

Now the only thing that is not working on this SE is the sound from the built-in speaker. The speaker connector is very corroded by the Maxell bomb that exploded in this machine. When I popped the pins loose from the white connector one of them was completely corroded off. I am going to replace the pins and the plug as soon as I get the parts. Hopefully that is all that is wrong with the sound. The headphone jack does work. (See my other thread on that.)

I make a little progress every week with it...

 

[olePigeon]

Excellent, keep at it.  Once you replace the speaker connector, hopefully you're all done.

Well, you're never really done.  Next you'll be buying accelerators, RAM, peripherals ...

 

[macosten]

Excellent to see! Resurrecting a board post-Maxellpocalypse... it's not something that happens often, if you know what I mean.

...and yes, olePigeon is right... Such a cute machine requires upgrades, software-wise and hardware-wise... I promise I'm not just projecting!

 

[jefframsey]

Excellent, keep at it.  Once you replace the speaker connector, hopefully you're all done.

Well, you're never really done.  Next you'll be buying accelerators, RAM, peripherals ...

Once I get it all refurbished, I think I am going to restore an Apple IIe next. But I may decide to do the SCSI2SD adapter, or a SCSI->Ethernet bridge, or an accelerator or...  

Excellent to see! Resurrecting a board post-Maxellpocalypse... it's not something that happens often, if you know what I mean.

...and yes, olePigeon is right... Such a cute machine requires upgrades, software-wise and hardware-wise... I promise I'm not just projecting!

I read somewhere on here that techknight has only ever resurrected one board from a Max-hell aftermath. Not saying that puts me in a category with him or anyone else. Just really shows how lucky I was that the damage was so localized on my logic board. And how grateful I am for all of the advice from the forum.  :beige:

 

[hunter44102]

Great news. Glad it all worked out. 

 

[olePigeon]

Once I get it all refurbished, I think I am going to restore an Apple IIe next. But I may decide to do the SCSI2SD adapter, or a SCSI->Ethernet bridge, or an accelerator or...  

I'd recommend your next purchase be a FloppyEmu.  You can use it with both your Mac and Apple II.

 

[Johnnya101]

Yeah, they are amazing!