Macintosh SE Logic Board axial capacitors replacement

[Gregory K]

Dear forum members,

I'm about to replace capacitors on a Logic Board of my Macintosh SE FDHD. Unlike later SE/30 models, the Macintosh SE Logic Board has axial capacitors installed. They are Nichicon SE (blue color).

The problem is I can't find any information about the discontinued "SE" series - I only know they are 85C. I don't know if they are Low-ESR, or Extended Life, or whatever...

It seems the only axial capacitors, which are currently in production (by Nichicon) are "VX" series, but they are "Standard For General Purposes, 85C". Will it be a correct replacement for a Macintosh SE Logic Board - or there are specific requirements for capacitors? Does anyone know anything about the Nichicon SE series - or it's equivalent?

Any info would be much appreciated.. Thank you!

 

[uniserver]

those are just general use 85c caps on there.

i'v not seen those go bad yet, not to say they wont though.

 

[uniserver]

nice pram battery

 

[Gregory K]

Oh, great! Thank you for your reply  

 

[techknight]

I have changed a few sets of those, I just use ones I can get from Mouser. Mouser seems to be the place to go when it comes to different capacitors types. Digikey doesnt have a good selection. 

 

[unity]

I too am sure there is an SE out there that needs new caps on the mobo, but I myself have never seen it yet.

 

[techknight]

they all do by this point. Sure they may not be leaking, but they could be drying out, or breaking down internally, and that creates leakage currents which is bad. itll heat the capacitor up. 

 

[Gregory K]

Thanks a lot for your information! I'm trying to fix an intermittent bug, so I think to change all electrolytic capacitors inside the machine.

 

[techknight]

explain the intermittent bug?

 

[uniserver]

intermittent stuff is almost always ram or power supply with the SE.  

 

[techknight]

yea, I have never had any logic issues on an SE. 

years and years ago, late 90s, I had an SE that had a VERY unstable power supply. Never did figure out what it was. would run fine, then it would go into a pulsing reboot frenzy. then it was fine again. then itll go into a single reboot pulse, and be fine. Very random. haha. 

 

[Gregory K]

explain the intermittent bug?

Thank you to everyone for your attention, I appreciate it very much!

The bug "seems" like an issue with the disk interface:

Sometimes, after deleting / moving a file on a hard disk, the 'Disk First Aid' software reports errors on the disk (usually about files attributes). Then, the software is able to successfully 'Repair' a disk, BUT (!!!) sometimes I then discover that some another file has completely disappeared from the disk..

Originally, I thought that this was the hard disk problem, so I replaced it with an SSD (using SCSI to SATA adapter made by Artmix) - but the problem is still there. Do you have any ideas what may cause it (if not capacitors)? 

Just in case, here is the configuration: Macintosh SE FDHD 4Mb RAM, OS 6.0.8. The floppy is 800K (from a regular Mac SE), because the original SuperDrive is broken, but I'm expecting a replacement SuperDrive floppy.

 

[techknight]

that sounds like system software or partition sizes to me. 

 

[Gregory K]

Unfortunately, the problem still exists even with the original Quantum 40Mb HDD (1 partition)..