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Actually, I got the highest peak-to-peak measurement on my very first press of the Programmer's Switch, prior to getting any Sad Mac.  That measurement at J11 (stock 63Ω speaker) was 8.24Vp-p.

Thank you for the extensive testing @ttb.  Again, I cannot remove my motherboard like you, but I am able to take scope voltage readings from the J11 speaker connector.  The video below shows exactly how I tested the stock 63Ω speaker and a MacEffects 8Ω speaker.  As I expected, the 8Ω speaker...

I re-read all of @aeberbach's previous posts.  He said he measured: • 5v on the positive side of C3, C4 and C5, individually • 12v peak voltage on C3, C4 (but he didn't mention if it was also on C5) It is very important that we know if all 3 of those caps see 12v, even if that 12v is merely a...

Thank you very much for your kind willingness to do that extra testing, @ttb.  Please also try pressing the Programmer's Switch so as to perform the exact same test as @aeberbach.  Curious if you see those +12V (0-peak) voltage spikes too.

Thank you for clarifying.  Now I am more confused about what @aeberbach said about having measured 12V "peaks". @aeberbach Can you please clarify that you did indeed measure 0-12Vpeak voltage at the pin-10 output of UB10 & also UB11 respectively using your scope?  And if you put both...

Wow. A great write-up and set of photos on their website.  Thanks for sharing!

Thank you again for your continued testing. Please don't desolder polymer or solid tantalums unless you want to throw them away.  As per manufacturer instructions, once the caps have been soldered onto a board, desoldering them only to later resolver them would put them out of spec.  The...

Here's the iCircuit document I created, which will allow you folks to play with the simulation yourselves (if you install iCircuit on your Mac, of course): The RMS power through output resistor R10 is about 126mW when both channels are set to 400Hz, using the stock 63Ω speaker.  But when I...

Thanks.  I've actually been putting together a YouTube video on the very subject of how to properly select capacitors for recapping projects -- general advice not tied to any particular vintage machine.  It was a part of my research for that video which prompted me to start this thread...

Compared to the stock "Wet Al" (Aluminum Electrolytic) capacitors, the impedance (Z) and ESR of both SOLID Tantalum (Ta-MnO2) and Polymer Tantalum (Ta-Polymer) is much lower at all frequencies.  Because there is no datasheet on the UB11 & UB10 sound chips and because I cannot pull my own...

@ttb Thank you for the time you invested in all of that testing. You did far more than I thought you would. What I thought you were going to do was test your solid tantalum motherboard and then test your polymer tantalum motherboard in the same machine (one at a time, obviously) using the same...

That comparison is welcomed because solid tantalums will have an ESR ranging from 0.7 to 1.1 ohm, depending on part number, which is much higher ESR than the polymer tantalums.

It's important to keep the terms straight.  "Leakage Current" is totally different than "leaked fluid."  You probably understand that already, but I just want to be 100% clear.  The 1989 stock caps leak fluid, and they also have very low leakage current.  Why so low?  Because all fluid filled...

Blasted that 45min. Edit post timer!  Ack! If you are dead set on buying "can" shaped replacements, these Solid Polymer Aluminum caps are more expensive than the WURTH caps I linked to in my previous post, but the leakage current is much lower at 150uA (versus 400uA for the WURTH, although...

No "objections" but I do have "reservations." :-) You have chosen HYBRID Polymer Aluminum capacitors (47uF).  Those are superior to the regular (stock) Aluminum Electrolytic capacitors in terms of low ESR, and in terms of "leakage current" they are superior to SOLID Polymer Aluminum...

That's great to hear.  I have selected some polymer caps already, but if you don't mind sharing what caps you chose, that would be helpful.  I am especially curious about ESR.  For most of the caps, low ESR is good, but I was wondering how it would affect the audio, since two of those caps have...

Thank you for confirming on a scope that you see 12V peaks on each of those 3 capacitors.  That's what I was afraid of. Transient peaks or not, anything above 8V is technically over-voltage regarding 16V Solid Tantalum capacitors which have a strict 50% derating requirement.  The likelihood of...

5V while the audio is playing, right? Thank you!

Have any of you ever measured voltages at UB10 or UB11 (Sony chips) on an SE/30 motherboard?  I don't have a long enough cable to safely pull out the motherboard to test that.  I am specifically curious if capacitors C3, C4 & C5 see a maximum of 5V or 12V.  I suspect one or more of those...

I highly recommend getting yourself a large sized, rubber rocket blaster, sold on Amazon, so you can safely clean dusk off the neck of that CRT.  A rocket blaster is safer than compressed air but really works just as well. Now you just need to restore that "for parts" Classic.  It's most...