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Getting G3 Whisper Perch USB working

Phipli

Well-known member
It won't work until you figure out what U9 is (as well as fitting the clock) because U9 is in line with the power to the port in your schematic.
 

Phipli

Well-known member
View attachment 53862

I've populated some more of the card tonight - the passives highlighted in green. It hasn't made any difference. The only other crucial part now, I think, is the oscillator.

One thing I've realised is that my other PCI USB cards no longer work - they are not even seen as USB cards anymore, just as unknown PCI devices. It might be a case of either/or if I get the Perch USB working.
I've just noticed you have caps fitted at R146, 147 and 148? These should be resistors?
 

croissantking

Well-known member
It won't work until you figure out what U9 is (as well as fitting the clock) because U9 is in line with the power to the port in your schematic.
I’d argue U9 isn’t needed.

See the attached photos from the CMD 0670 manual.

They give three options for power connection. U9 might well be intended for the UCC 3912 it shows as option 3.

It states to only use one option. So my thinking is that if I have the fuse onboard, I won’t need the chip.

On my Whisper schematic, it looks like the 5v needed to supply bus power would come from VDD on the other side of the fuse. U9 is kinda separate from that circuit. If I were to integrate U9, I would omit the fuse and bus power would come from the chip itself along the same pathway.

The Wings card doesn’t seem to have this chip as part of the footprint at all, although it does have the fuse and big capacitors, again backing up the idea that it’s optional.

F77430D5-A74C-4D0B-B72D-058D6EDBABAF.jpeg
6EE389FE-2120-4724-A230-3DC48505536A.jpeg
 

Phipli

Well-known member
I’d argue U9 isn’t needed.

See the attached photos from the CMD 0670 manual.

They give three options for power connection. U9 might well be intended for the UCC 3912 it shows as option 3.

It states to only use one option. So my thinking is that if I have the fuse onboard, I won’t need the chip.

On my Whisper schematic, it looks like the 5v needed to supply bus power would come from VDD on the other side of the fuse. U9 is kinda separate from that circuit. If I were to integrate U9, I would omit the fuse and bus power would come from the chip itself along the same pathway.

The Wings card doesn’t seem to have this chip as part of the footprint at all, although it does have the fuse and big capacitors, again backing up the idea that it’s optional.

View attachment 53875
View attachment 53876
Ah yes, the fuse isn't in line and has its own connection to Vdd.
 

croissantking

Well-known member
I’ve replaced the three wrongly fitted caps with resistors and added in an oscillator:

4ADD741E-AAC1-46AC-A5DE-68B83985918E.jpeg

ASP now lists a USB bus:

A4A3814C-1034-44AF-A121-264A4E4592EA.jpeg

This is awesome progress. However, devices that are plugged in do not show any signs of life nor are they recognised.

However a secondary 4 port PCI USB card now works again (5 buses are listed with it installed).

A quick look at the USB log window shows a long list of events with reference to a ‘dead port’:

ADC1CF48-3CCD-4BCD-B39D-3F6FE6AB94C3.jpeg
 

Phipli

Well-known member
Gi en the error, I'd start by checking that pins 9, 10, 11, 22, 23 and 24 are set up correctly.

Some of those pins are to do with verifying the correct voltages, if you don't have them wired in correctly, the chip will decide the supply isn't working and report a bad port.

It's 3 pins per port.
 

croissantking

Well-known member
Also those resistors relate to the secondary USB port which does not exist on the footprint, therefore in reality maybe there is supposed to be a ‘dead port’
 

Phipli

Well-known member
Just seeing what your decision process was. I think that's OK, but a couple more things.

What is that clock sat on? Don't let it short anything.

What is pin 11 connected to? Your schematic shows it unconnected, but I think it should be connected to something.
 

Phipli

Well-known member
You'll have to forgive me, I haven't looked at everything in detail so I'm trying to ask things about stuff that might be an issue, or I don't understand. I'm asking lots of dumb questions, but hopefully it is still useful :)
 

croissantking

Well-known member
You'll have to forgive me, I haven't looked at everything in detail so I'm trying to ask things about stuff that might be an issue, or I don't understand. I'm asking lots of dumb questions, but hopefully it is still useful :)
Yes, keep it up, with your input I'll get this solved 2x faster. Don't hold back!
 

Phipli

Well-known member
It does. I just updated my schematic. I put 10k resistors on those, no idea if they're right.

View attachment 53939
Those won't be 10k and this would cause the issue you're seeing. That is a potential divider.


Ideal would be to get values from another mac of similar age (sorry, but there is a gap in my collection, I don't have anything from the early G3 era after beige).

If not... make R76 about 4 times bigger than R76 R75... guessing.
 
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