Mac IIsi, no sound

[reallyrandy]

Running 7.0.1.

I know I've read something about this before but I can't remember what I could even check. I think this is a common problem.

Anyone know anything about it?

Thanks,

Randy

 

[bibilit]

Caps maybe.....

 

[bigmessowires]

That's a common symptom of failed capacitors on the logic board.

 

[reallyrandy]

I'll have to get it recapped probably.

 

[blitter]

It's also possible that the connection from the speaker itself to the logic board might be faulty. My dad had a IIsi with an oxidized speaker connection-- this is a common problem with that model. If a sharp rap to the top of the case will occasionally restore sound, that might be the issue.

 

[tanuki65]

I had a IIci, recapping gave it sound

 

[AlpineRaven]

Failed caps - my IIsi is the same. I will re-cap it when I bite the bullet for it.
Cheers

AP

 

[Unknown_K]

Take a look at the board and see if the capacitors have leaked all over. Bad capacitors in the audio circuit will kill sound, some machines like the LCIII will whistle while they die (unit will not turn on again without a recap).

 

[AlpineRaven]

no sound could be indication that the caps are gone as said above. My IIsi has that problem too.
Cheers

AP

 

[mac57]

I think blitter had it right - I have a IIsi with the same problem, and I have read repeatedly that the design of the speaker placement leads to poor speaker connections over time. I have never tried the "sharp rap to the top of the case" solution - I may just try that! In the meantime, I am just looking for some external speakers instead. I do not want to spend an eternity (or much money!) trying to get the internal speaker to work. I have a Quadra 840AV with the same problem (but related to caps this time), and I have "solved" it the same way. Seems to resolve the majority of the issue.

 

[IIfx]

If you have leaking caps eventually the external speaker will fail as well. The electrolyte will eat away at the motherboard. It's not a solution, it's a band aid on a missing limb.

In my experience Macs made prior to 1995 are starting to have their caps fail en masse. I now have a small pile of dead machines awaiting recap as a result. I waited a bit too long and there is some minor damage on some boards from corrosion.

 

[mac57]

Quite agree... I am buying time, not solving the root problem!

 

[sigtau]

IIsi has considerably easier caps to replace than, say, the IIci or IIcx.  The caps for the audio filter circuit are in the northwest corner of the board (if 'north' is where all the rear ports stick out).  If replacing those fixes your audio issue, you know the caps were bad.

 

[bibilit]

On the IIsi, i will add some tin on the underside of the board, where the speaker is making contact, will help to improve the setting.

 

[richlove]

IIsi has considerably easier caps to replace than, say, the IIci or IIcx. The caps for the audio filter circuit are in the northwest corner of the board (if 'north' is where all the rear ports stick out). If replacing those fixes your audio issue, you know the caps were bad.

Thanks for the info on the caps. It fixed my sound problem. However, the caps are located under the power supply near the headphone jack. See the red arrows for the three caps I replaced to fix the sound. I used 47 uf Tantalum caps.

 

[volvo242gt]

It might also be a good idea to clean/tin the contacts for the fan. Same issue occurs with the fan as what happens with the speaker. If the contacts are oxidized, it will cut out. In this case, don't tap on the fan. Instead, shut the computer off, pull the fan and clean the contacts. Ask me how I know. It is the reason why I wound up owning two IIsi machines within three years back in the '90s.