I have a 512K Macintosh that wouldn't do the bong when you start up. It would otherwise work fine. I checked the Control Panel volume and still didn't hear any sound. I also tried some games where I knew sound was present, but nothing. So in short - no sound at all. Then I plugged in headphones and I could hear all sounds through the headphones, including the startup bong.
I troubleshooted per Michael Pina's book: RF Shield short on J1 - no issue, battery B1 - no issue, Sockets J4 and J7 reflowed - no issue. Tested ohm from speaker - issue found: Open loop present.
I removed the speaker from the analogue board and found that it had an open coil. in fact when you move/shake around the speaker you could hear the lose part.
Now I'm looking for a replacement speaker on eBay:
Per Michael Pina's book, I can replace the speaker with a 4 Ohm, 8 Ohm, etc. as long as the Wattage is holding up. No less than 4 Ohm, 4W (or 8 Ohm 2W, 16 Ohm 1W, ...)
I found many speakers in that range, but very few of them have the 4 mounting holes I would rely on to attach the speaker back in the original spot.
If anyone has done such a replacement, it would be awesome to hear what speaker they used to replace it with that was a close to original fit.
I found these ones and per measurements, it should actually fit. Can anyone confirm?
57MM 8Ohm 8Ω 10W Full-range speaker Loudspeaker Neodymium Rubber edge
Per attached measurements, this should be an exact drop in replacement. it sticks out a bit more, but I verified there is no obstructions in the case, so the speaker mounting location can accommodate a deeper speaker like this. The Watt rating is a bit higher on this one, so it should sound better/louder, too.
For reference, this is the original speaker I took out from the Macintosh.
I troubleshooted per Michael Pina's book: RF Shield short on J1 - no issue, battery B1 - no issue, Sockets J4 and J7 reflowed - no issue. Tested ohm from speaker - issue found: Open loop present.
I removed the speaker from the analogue board and found that it had an open coil. in fact when you move/shake around the speaker you could hear the lose part.
Now I'm looking for a replacement speaker on eBay:
Per Michael Pina's book, I can replace the speaker with a 4 Ohm, 8 Ohm, etc. as long as the Wattage is holding up. No less than 4 Ohm, 4W (or 8 Ohm 2W, 16 Ohm 1W, ...)
I found many speakers in that range, but very few of them have the 4 mounting holes I would rely on to attach the speaker back in the original spot.
If anyone has done such a replacement, it would be awesome to hear what speaker they used to replace it with that was a close to original fit.
I found these ones and per measurements, it should actually fit. Can anyone confirm?
57MM 8Ohm 8Ω 10W Full-range speaker Loudspeaker Neodymium Rubber edge
Per attached measurements, this should be an exact drop in replacement. it sticks out a bit more, but I verified there is no obstructions in the case, so the speaker mounting location can accommodate a deeper speaker like this. The Watt rating is a bit higher on this one, so it should sound better/louder, too.
For reference, this is the original speaker I took out from the Macintosh.