Classic II startup stalls with no disk activity, no bong (full recap done)

[TheReducer]

I bought a Mac Classic II (rev b) locally for $30 - nonworking. It started up to black/white vertical bars.
I found the ROMs were not positioned properly, and after positioning them correctly, the black/white bars went away. The system then started up to a blank gray screen with cursor that I could move with the mouse. But, no bong startup sound and no disk activity.

I completed thoroughly cleaning and recapping both the analog board and logic board.
After this work, the startup behavior is exactly as before. Disconnecting the SCSI hard drive does not change the behavior - I'm still not prompted for a floppy boot disk when starting up - just a blank gray screen with mouse cursor that I can move with the mouse.

Video of startup:
https://drive.google.com/file/d/1JzVAwHMhhhDi2UlU3v5IjZ_FbMA1qToe/view?usp=sharing

I'd appreciate any advice on what to do next.
What I'm considering:
* Remove U8 (the SCSI chip), clean and check all traces before re-soldering.
* Test the speaker with ohmmeter (should measure 60 ohms)
https://68kmla.org/bb/index.php?threads/macintosh-classic-ii-with-no-sound-analog-board-issue.37732/
* Remove U4 (DFAC - sound chip), clean and check all traces before re-soldering.

Thanks for any advice!

 

[moldy]

I can only suggest that the intermittent boot behavior of my Classic II was fixed by desoldering and cleaning the cap goo under EGRET.

 

[TheReducer]

I can only suggest that the intermittent boot behavior of my Classic II was fixed by desoldering and cleaning the cap goo under EGRET.

Thanks for the reply, I'll consider the EGRET as a candidate for removal, cleaning and re-soldering as well.
Note that the boot behavior on my Classic II is not intermittent, but is always the same now that both ROMs are correctly inserted.

 

[cheesestraws]

Do you get a bong through headphones? In other words, is it the actual sound that's gone or is it just the speaker?

 

[TheReducer]

Do you get a bong through headphones? In other words, is it the actual sound that's gone or is it just the speaker?

I do not get a bong through the headphones either. So, you do make a good point - it is not just the speaker.
I've decided my first priority is to get the SCSI and floppy access working so I can boot the machine.
Currently I do not get a sad Mac or a ? Mac - just a mouse cursor I can move around on a blank gray screen.
After I have the machine booting, I'll tackle the sound problem.

So, looks like I need to remove, clean and resolder:
- U8 (the SCSI chip)
- EGRET chip
(hopefully the machine will be booting after this)
Finally:
- U4 (DFAC - sound chip)

I have not worked on SMD boards much, so I'm going to practice on some junk boards first to learn how to remove ICs with hot air.

 

[Jamieson]

What does EGRET chip do?

 

[TheReducer]

What does EGRET chip do?

EGRET (Motorola 341S0851) controls reset, and I think also PRAM, RTC, ADB.
https://wiki.preterhuman.net/Apple_Computer_Custom_IC_Definitions.

 

[jajan547]

Reflow egret with flux should do it had a similar issue not too long ago

 

[joshc]

Egret is worth a clean/resolder but if Egret is bad I don't think you'd be getting as far as a blank grey screen with cursor. By that point, most of the startup routine has been done, and it's read from ROM already, it's just looking for an OS to boot from.

Pictures of your board would be good, is there any cap goo left under chips?

 

[jajan547]

Egret is worth a clean/resolder but if Egret is bad I don't think you'd be getting as far as a blank grey screen with cursor. By that point, most of the startup routine has been done, and it's read from ROM already, it's just looking for an OS to boot from.

Pictures of your board would be good, is there any cap goo left under chips?

I second this show us the board