I have 2 Pismos. The audio was the most problematic in both. I use the pismo full functions, audio in and output on the 1/8" jacks on the back. This is where the problem is. Although I did have a hum problem generated by a generic adapter (with 3 prongs) I also found the generic power adapter spiked and caused the internal charge control circuit to blow. I use only the Apple yo-yo supply for both now, to be safe, and it is solid. I am in Canada, and I rarely have had ground/earth loop problems with 50/60 cycle hum, usually it comes down to a badly soldered cable (ie RCA jacks from mixer to power amp)
So, back to the Pismo, and it's sound card issues. When you crack open a Pismo, it's very basic and most components are fully replaceable if needed. The first Pismo, I had major issues with. When I had jacks in both the In and out of the sound jacks, I actually had an incident where the Pismo Sparked electricity and smoked. This was dramatic. Luckily it only blew the sound module. What I found was this particular Pismo had some shoddy work done on it. The previous owner(s) had done very bad Soldering for some reason and there was almost a bridge made from one point to another on the sound module and in the case of pluggin in the jacks to both the IN and OUT, it would create a full bridge of solder so it shorted the bugger out and almost caused a fire. On the sound module board, you also have the Power input, which itself is a bit flimsy. This is a point to really consider. Since the frequency modulation of the Power input can affect audio easily, you have to wonder why they would mount the power adapter on the sound board. So, I simply ordered a new component to replace the fried one. This Pismo now became my test unit. Before I popped that card/component into the Pismo, I did some reinforcing with Hot Glue Gun. This was easy and is actually what I consider now to be an essential fix for any Pismo owner. You want to make the joints more solid and load them with hot glue, taking care only fixing/covering points on components on the card itself, don't get glue inside the jacks or cover contact points for the 1/8" jacks. Also I made a glue block/hump between the Power input and the audio in to block the frequency interference from the power. When I mounted the card, I also put hot glue at certain points to make it not as flexible but keeps it stable and no longer visibly flexes when you insert your audio jacks. I know a video would do this much better. What it comes down to is a basic understanding of circuits and layout design reinforcement. I ended up using hot glue on other points on the innards of the pismo to just reinforce things. Since they are cheap to find now, and i have a good understanding of how to basically build a Pismo at this point if need be, I was not afraid of experimenting a bit. This Pismo is now and still my main laptop. There has been zero issues with any sort of audio since the upgrade. If your soundcard is shot, you can get one on ebay for under $20.00, sometimes the power supply adapter that charges the battery gets killed, those are also under $20.00 on ebay. I also have concluded that using certain generic power adapters are garbage and should be avoided. If I plug the Pismo in with my generic one I get 60 cycle hum. With the Apple Yo Yo, nothing but clarity. So there is no rule, there are variables, and you may have to try a few things. I may make a video soon to post on youtube about the hot glue technique. ..anyone interested? -- You received this message because you are a member of G-Books, a group for those using G3 iBooks and PowerBooks (we run a separate list for G4 'Books). The list FAQ is at http://lowendmac.com/lists/g-books.html and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To leave this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g-books Support for older Macs: http://lowendmac.com/services/
