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LC II - no chime, no display after recap

Katakis

Member
I got my Mac LC II recapped last week after 4 years of storage. When I got home to test it out, everything was working perfectly; there was a chime and I got a display. Even the SCSI HDD I got my technician to install also was working perfectly. I told him the good news and he was pleased. Unfortunately, I was tricked into thinking it works, because after that I am now receiving no chime or display upon bootup. The reason why there could be no chime was because my technician also detected a bulge in the audio capacitor? Are there any ideas why this would be a one-off?
 

Nixontheknight

Well-known member
I’d say the entire board needs to be recapped at this age, any macs from the early to mid ‘90s will all need to be recapped at this point
 

joshc

Well-known member
Your LC II probably won't work reliably until the logicboard is fully recapped and the PSU is also recapped.

Some photos of your board would be good to identify is there is anything else going on.

I also wouldn't put much faith into a SCSI hard drive at this point, even if they work they tend to fail pretty soon after. Get a SCSI2SD or BlueSCSI instead for it.
 

Nixontheknight

Well-known member
You mean those yellow things that replace surface-mounts? This is the first time I ever heard about it, but I only found out from recapamac.com.au
Yes. Tantalums are better than electrolytics in many ways, but they're only meant for low voltage applications like motherboards. For the PSU, you have to replace them with newer electrolytics for the time being
 

zezba9000

Well-known member
You should only need to replace the electrolytic caps. If it worked before its probably not the PSU atm.

Are those pictures of the board after you recapped? Did you use heat gun? Did you pull up any traces?
Did you wash board off with IPA (isopropyl alcohol)?
Or Its possible you broke a trace. Go around each chip you soldered & check its pin in making a connection with other parts of the board.
 

Katakis

Member
You should only need to replace the electrolytic caps. If it worked before its probably not the PSU atm.

Are those pictures of the board after you recapped? Did you use heat gun? Did you pull up any traces?
Did you wash board off with IPA (isopropyl alcohol)?
Or Its possible you broke a trace. Go around each chip you soldered & check its pin in making a connection with other parts of the board.

Yeah, the entire board was recapped and IPA was used to clean the area around the capacitors. During replacement, fresh solder joints checked and cleaned with isopropyl alcohol. Not sure about the traces, but I think they are untouched. My technician also noted that one of the 100uf caps (audio capacitor?) was bulging, yet there was no problems with sound the first time I used it after replacement.

P.S. I usually get the capacitors from RS Components, and there are 2 types: Hybrid and Electrolytic. Does it matter if some of the capacitors are Hybrid?
 
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joshc

Well-known member
I can see some gunk around the legs of the Egret chip which is a vital part of the startup circuit on these.

1642489521691.png

UB9 also looking particularly dirty still

1642489546480.png

I would check continuity of everything in that corner and go from there, but I think more cleaning wouldn't hurt either.
 
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