SE/30 really weird startup sound

[amedeo_68k]

Hi,

One of mine SE/30 emits this bad trimmed startup chime, I also triggered death chime by pressing interrupt, it also gets emitted weird.
Also the display would be full of vertical lines like jail

Any ideas ?
Thank you

 

[Byrd]

What are your specs, is everything recapped?

My accelerated SE/30 with stock ROM emits a half chime at startup, but in the OS sound is fine. Using a IIfx ROM I get a full chime.

 

[amedeo_68k]

Standard config. Stock rom, Fully recapped.

 

[joshc]

Got any photos of your board? How recently was the recap done? Did it work after recap and it's only just started doing this?

Is the PSU recapped, strong voltages?

 

[Bolle]

Broken address line somewhere around the ASC. A0, A1 and A2 pass along under the ASC close to that one leaking cap that also kills UE8 ever so often.
If an address line breaks there you will get faulty audio and video.

 

[mg.man]

Just a quick cross-post confirming that A0 / A1 issues can definitely impact sound. In addition to the video corruption I was having, I was also having sound problems. Making sure A0 / A1 are connected to the right places fixed video and sound on a SE/30 I've been working on for several months!! Thanks @Bolle!

Well... I finally had a chance to do just that today. But before I took the drastic action of removing and replacing UE8, I decided, spurred on by @Bolle's post over in another thread :

...to do some more buzzing around. This was also prompted by the fact that I'd buzzed all the connections from UE8 a week or so back and they were fine. Well... whaddayaknow... @Bolle was right - I did have issues with A0 and A1 connectivity - to various places including the Video ROM, ASC and GLUE. Here's my solution :

View attachment 43401

NO, it's not pretty - I *will* tidy this up. But... just to be clear... TA DA :

View attachment 43402

NO MORE video corruption!!! Big thanks to @Bolle and the rest of the MLA community!

 

[amedeo_68k]

Hi, I have just removed ASC and UE8, traces doesn't look bad, posting pic

 

[Bolle]

Have you checked continuity for the address lines going to the ASC? It doesn’t necessarily need to be a visible break somewhere. Also no address lines go to UE8, wouldn’t have been necessary to remove that.

Check continuity for all the address lines going to the ASC and to the video muxes. Test between CPU/PDS/ROM slot and the ASC/muxes.
Chances are high it’s either A0, A1 or A2.

 

[amedeo_68k]

Thank you, I'm going to test, do you have the board schematic ?

 

[Garrett B]

Check it out here:

macse30mlb/hardware/pcb/mlb/output at master · mishimasensei/macse30mlb

Macintosh SE/30 Main Logic Board Schematic Drawings - mishimasensei/macse30mlb

github.com

 

[amedeo_68k]

thank you, just checked, continuity from CPU / PDS / ASC are good

 

[amedeo_68k]

Address lines seems to be good. I’m going to put ASC back in place, but UE8 chip legs are not looking very good. A good replacement?

 

[halkyardo]

I had a similar problem with an SE/30 that I recapped recently - mine would sometimes boot fine, but other times get stuck in a similar-sounding loop, and when it would running, it would crash in that way if any sound was played. The problem ended up being a shorted trace hidden under one of the audio-filter caps (C4, I think) causing audio signals to trigger the power-on reset circuit.

I don't think that would cause the jailbars, but it might be worth checking the traces under those caps.

Recapped SE/30 crashes/resets when playing sounds

I've just finished recapping an SE/30, and have a puzzling problem: while the boot chime is loud and clear and sounds normal, playing any sound while the system is running causes it to lock up and play a 'stuttering' boot chime for a second or two, and then restart - as if somebody pushed the...

68kmla.org

 

[amedeo_68k]

hi, I'm going to take a look, btw, I noticed that the ASC (UE10) becomes quite hot

 

[amedeo_68k]

Wow, after a few quick power on/off repeatedly (by mistake, running on external psu), now the machine won’t chime at all, is there a way to check if I have fucked the CPU ?
thank you