SE/30 volume not adjustable after logic board recap

[fehervaria]

I finished my SE/30 full recap. Everything works as expected only one thing:
I can not change the volume in the Sound control panel. If I set to 0, then the menu bar blinks, but then at 1 and any other till 7 -> is the "same loud".
Do you have any idea what could cause this behaviour?
Previously the sound was very weak and scratchy.

EDIT 1:
I checked both, speaker and headphones too, the volume not adjustable and it set to the maximum value.

EDIT 2:
After repair the connection between UE10 Pin-33 and UB10 Pin-4 (and UB11 Pin-4) and
repair the connection between the C5 + and UB11 Pin-7
the volume control works as it should.

 

[Stephen]

I finished my SE/30 full recap. Everything works as expected only one thing:
I can not change the volume in the Sound control panel. If I set to 0, then the manu bar blinks, but then at 1 and any other till 7 -> is the "same loud".
Do you have any idea what could cause this behaviour?
Previously the sound was very weak and scratchy.

Did you wash your board in any way? I wonder if you inadvertently "sloshed" some tainted fluids into the amp / controller (I don't know which chip has this job).

 

[fehervaria]

Did you wash your board in any way? I wonder if you inadvertently "sloshed" some tainted fluids into the amp / controller (I don't know which chip has this job).

Yes, I washed the board in multiple levels: warm soapy water, let 2 weeks drying on the heater then IPA (not just rubbing around, proper draw in IPA).
Of course, after the IPA wash, I let it dry few days as well.
I use this method always with my stuffs because I don't have ultrasonic cleaner (yet) - but I never had any problem with any of my stuffs.
So, I just wondering. It feels the volume is set to the maximum possible level...

 

[JDW]

Attila,
Connect headphones, then try changing the volume and report back if the volume is still the same at 1~7 or if it changes.

 

[fehervaria]

Thank you James.
Yes, I've checked it already in the time of the original post, just edited right now and added this information too.
Both, speaker and headphones, has the same volume, I feel it is the maximum value.

Based on the attached picture, UB10 and UB11 are responsible for the sound, C2 as a new radial capacitor.

Copyright for the picture: I don't remember where I find it, I downloaded it approx. a year ago. If the original author recognise the picture, pls contact me.

 

[Bolle]

Check the volume control signal lines between the ASC and the Sony chips. They'll either be open or you shorted them while replacing the caps in the audio section.

 

[fehervaria]

I shecked everything from multiple direction. There are no shortened nor cutted connections anymore.
I checked from C2 to C7 every connection based on the image I posted earlier. I find the C5 + was not connected to UB11 Pin7, but I corrected it with a air-wire. I resoldered ALL of the pins of UB10 and UB11.
The volume is still set to maximum value. I checked with System 6.0.8 and System 7.1 and with speaker and headphones is the same, max. level.

Any other idea what could cause non-working volume control - max volume level?

 

[fehervaria]

Check the volume control signal lines between the ASC and the Sony chips. They'll either be open or you shorted them while replacing the caps in the audio section.

Could you tell me whitch ASC "signal lines" connected to the Sony ICs?


EDIT-1:
Based on the Apple's schematics the relevant pins from ASC (UE10) are the Pin-31, Pin-32 and Pin-33.
These are connected to UB10 and UB11, to Pin-2, Pin-3 and Pin-4
Sources: Macintosh SE/30 Main Logic Board Schematic Drawings and directly in PDF, Page 7

 

[JDW]

Could you tell me whitch ASC "signal lines" connected to the Sony ICs?

Yes, the 3 wires on that schematic marked SV0, SV1 & SV2.

However, I myself have never checked the voltages on those wires, so I do not know what the normal level should be according to the Control Panel volume setting. I guess you should check to see if the voltage levels change when you change the control panel volume.

 

[fehervaria]

SUCCESS!

After checking all the outcoming lines from UE10, then I catched a disconnected Pin between UE10 Pin-33 and UB10 Pin-4 (and UB11 Pin-4).
Repairing it with air-wire, then we have all 3 Pins of UB10 (Pin31, Pin32 and Pin33) connected to both UB10 and UB11 (Pin-2, Pin-3 and Pin-4)

...and now, it works: the volume control able to set to quiet (setting 1) and loud (setting 7) and all levels between them...
Thank you for @Bolle and @JDW for the hints.

 

[JDW]

 

[Bolle]

However, I myself have never checked the voltages on those wires, so I do not know what the normal level should be according to the Control Panel volume setting.

They're active high logic signals, so it's either 5V or 0V.
SV0 is grounded and always inactive.
The other 8 volume levels are just formed by counting through all possibilities in binary:

Volume Level | SV1 - SV2 -SV3
0 | 0 - 0 - 0
1 | 1 - 0 - 0
2 | 0 - 1 - 0
3 | 1 - 1 - 0
4 | 0 - 0 - 1
5 | 1 - 0 - 1
6 | 0 - 1 - 1
7 | 1 - 1 - 1