Crackle and tons of nasty SMOKE! Mac 512Ke).

[gnolivos]

I had finally gotten my old Mac 512Ke together after a mildly successful floppy reapir, and after about 1 hour of use it started going crackle crackle and then a whole lot of DENSE NASTY SMELLING WHITE SMOKE... woah!  I pulled the plug immediately.

opened her up, and cant seem to find any burned capacitors on the ANALOG BOARD just from a quick look.  Have yet to check the logic board.    Which caps of analog and logic board are common suspects?  If there is a re-cap guide for compact Macs please point me to it (I cannot find it, but I read plenty references to it on this forum!)

Thanks!

 

[uniserver]

its fine..  the ac filter cap blew.. you can still run it with out that cap, it burns up and then it becomes open.

or if it smokes some, it will eventually stop.  and you can just keep using it.

 

[gnolivos]

Okay I see. I'm going to replace it. I assume it is C 37 in my international board. Attached is a picture, I think I see a crack.

Most replacement guide to say to use a Y spec capacitor. This one is labeled as X spec however.

 

[uniserver]

Yup, you got it  

 

[CompuNurd]

its fine..  the ac filter cap blew.. you can still run it with out that cap, it burns up and then it becomes open.

or if it smokes some, it will eventually stop.  and you can just keep using it.

Just keep using it? Isn't the capacitor there for a reason?

 

[uniserver]

yeah its to keep switching psu noise from going back into the power.

Some people have fancy circuit breakers, and they could pop from it.. but most people are fine.  I have a couple machines I run,  a 512k / Apple IIe  that i still run after those blew.  I have a whole drawer of those filter caps,  my personal stuff has been getting neglected. 

 

[gnolivos]

Do you have a spare You want to get rid of?

 

[gnolivos]

Where do you guys recommend shopping for capacitors...?  From my international board, it looks like I will need a 0.47uF X-type polypropylene metalized capacitor. (C37)

Also while at it it looks like C33 and C36 are smaller, but same type, and would be wise to replace... those are Y-type  4700pF.

Anyone have a link to the handy excel sheet with replacement guide for common compact Mac caps?

 

[uniserver]

Just hit mouser.com they are pretty good.

i don't have those smaller ones in stock right now,  you should change those too, they look like they are ready to blow as well.

 

[gnolivos]

Ok, I think these are the best replacements.  What do you think uni?

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=162607639&uq=635536740540146454&CSRT=6333285681771440465

http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=162607642&uq=635536740540146454&CSRT=6333285681771440465

 

[uniserver]

for some reason the links are not working for me.

 

[gnolivos]

Strange.  I just double checked and they work fine for me 

Search digikey.com for parts:

PME271YA4470MR30

PME271M647KR30

for some reason the links are not working for me.

 

[uniserver]

what is wrong with these over at mouser?

71 cents vs 3.78

http://www.mouser.com/ProductDetail/Kemet/R46KI347000N0M/?qs=sGAEpiMZZMv1cc3ydrPrF512ADDNLQZJFjA1FVEOIUQ%3d

http://www.mouser.com/ProductDetail/Kemet/R413F147000M1M/?qs=sGAEpiMZZMv1cc3ydrPrF512ADDNLQZJ0Yjzq%2flnmrI%3d

51 cents vs 1.26

 

[gnolivos]

Uni:  Hrmmm...  so those you posted are Metallized Polypropylene Film.   The ones I posted are Metallized Paper Film.   I think the original ones are paper, no?

The price for the same part (all else equal) is about the same on both places.  I think Digikey ships cheaper to me that's all...

 

[uniserver]

yeah i'd get the mouser ones, they will work great,    Don't you think Polypropylene would be better then paper?

 

[gnolivos]

uni: I don't really know what the difference would be between the paper and the poly ones.  If anyone knows the correct type, please chime in!

 

[Paralel]

You're better off going with the poly ones. They will hold up better over time.

 

[tomlee59]

I second that recommendation. Poly over paper. Always.

 

[gnolivos]

Thanks.