SE/30 Reloaded Board - First Test
- Thread starter Steve Rieck
- Start date
Wow...The Reset button works and if I hit the Interrupt switch I get a low volume mangled death chime which seems to change a little if I push on the ASC....That's some progress. I'm hoping that might be a good sign that the GLU chip survived from the old board? If it's finding a death chime, that's coming from the ROM and that wouldn't be possible if the GLU was not working?
There is also a click coming out of the speaker every time it starts as if it's trying...
I've verified it's not the Video ROM or PAL chips as I just swapped those with known good and still Simasimac.
There is also a click coming out of the speaker every time it starts as if it's trying...
I've verified it's not the Video ROM or PAL chips as I just swapped those with known good and still Simasimac.
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Did you already check the PSU voltages? They tend to be a bit weak with the original PSU (even recapped ones). My SE/30 refuses to boot with low voltages, also yielding a Simasimac pattern…
Otherwise, double check your socketed ICs and make sure the contacts are pristine. Also check the sockets for residual flux etc..
Otherwise, double check your socketed ICs and make sure the contacts are pristine. Also check the sockets for residual flux etc..
I did when I recapped the PSU but I'll check that and the sockets again.
Am I correct that if the interrupt button gives me a mangled death chime, the CPU, GLU and ROM are awake? That would be encouraging.
Thanks for your help!
When you hear a death chime, your Mac is actually executing code, which is very good so far!
That is good news. Assuming soldering is ok (I will recheck everything) and no bridges, I wonder what I can confidently exclude as a cause at this point? To sum it up:
Symptoms:
- simasimac/horizontal bars (depending on which VRAM chips).
- speaker click and no other sound on start
- reset switch working
- interrupt switch produces a low volume mangled death chime. Definitely a death chime though. Unmistakable rhythm (4 1+2+...) The pitch changes by pressing on the ASC.
Good:
- PSU Voltages
- Working & Tested ROM, RAM, PALS, VRAM and VROM
Things I question:
- CPU Can I assume this is working considering the death chime?
- GLU Can I assume this is working considering the death chime?
- The rest of the PLCC Chips.
- ROM Socket All pins have continuity.
- RTC
- ASC Something is definitely wrong here. May just be pins not contacting.
- Y3 Part recommended by Bolle on mouser so I'm confident that should be ok.
- FPU
- Bourns Filters
- Sony Chips
- Y2
Thanks very much to anyone who can offer advice.
Symptoms:
- simasimac/horizontal bars (depending on which VRAM chips).
- speaker click and no other sound on start
- reset switch working
- interrupt switch produces a low volume mangled death chime. Definitely a death chime though. Unmistakable rhythm (4 1+2+...) The pitch changes by pressing on the ASC.
Good:
- PSU Voltages
- Working & Tested ROM, RAM, PALS, VRAM and VROM
Things I question:
- CPU Can I assume this is working considering the death chime?
- GLU Can I assume this is working considering the death chime?
- The rest of the PLCC Chips.
- ROM Socket All pins have continuity.
- RTC
- ASC Something is definitely wrong here. May just be pins not contacting.
- Y3 Part recommended by Bolle on mouser so I'm confident that should be ok.
- FPU
- Bourns Filters
- Sony Chips
- Y2
Thanks very much to anyone who can offer advice.
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Have you checked all the 74 series logic thats interfacing with the RAM?
Does that refer to the smaller F258 etc IC's between the RAM slots and the battery? (sorry, I'm just learning this stuff.) I've been sort of disregarding those as they were factory installed.
If you're getting different behavior based on pressure on/near the ASC, you should start there. That chip could be the culprit. Check all the legs with a meter for proper continuity to connected components based on the schematic.
Never disregard anything when diagnosing - after all, the original run of boards had transistors fitted at the factory, not diodes.
well not completely disregard. They were just down on my list… Will check it out tonight. Thanks.
