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.
Tonight I swapped out parts with one of my working restored SE/30's....just to see.
- Swapped out the 5 PAL Chips - No Change
- Swapped out Y3 Crystal - No Change
- Checked continuity on all 74 series logic and no issues. Need an oscilloscope to see more.
- Tried to swap out the 4pin Y2 Oscillator but the pin on the ground plane was so stubborn I gave up on the working board for fear of damaging it.
I did get Y2 off of the reloaded boarded. I started that board without it, resulting in no video/no sound as expected. Put it back on and back to where we were. Distorted death chime with NMI.
So I can rule out any issues with PAL chips, Y3 crystal and probably Y2 ? as well as the rest of the stuff mentioned earlier.
- Swapped out the 5 PAL Chips - No Change
- Swapped out Y3 Crystal - No Change
- Checked continuity on all 74 series logic and no issues. Need an oscilloscope to see more.
- Tried to swap out the 4pin Y2 Oscillator but the pin on the ground plane was so stubborn I gave up on the working board for fear of damaging it.
I did get Y2 off of the reloaded boarded. I started that board without it, resulting in no video/no sound as expected. Put it back on and back to where we were. Distorted death chime with NMI.
So I can rule out any issues with PAL chips, Y3 crystal and probably Y2 ? as well as the rest of the stuff mentioned earlier.
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I learned a lot from this! Removing non-essential chips, I now get the death chime at startup...so I'll add the chips back one by one until I determine which one is causing no boot (death) chime.
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Weird. When I remove just one of the VIA chips UK11 or UK12, I get a death chime at startup. That's progress maybe. New at least.
When both VIAs are in, I get just the pop sound as before. I swapped the two chips around with the same result. All other chips are in.
Even weirder, when both VIA's are in but I remove all RAM, I also get the death chime at startup.
I only get the pop sound rather than the death chime when both VIA's are in with RAM installed.
Regardless, with any configuration, I get the death chime with the NMI.
Very confused... also, it is the slow death chime which I believe indicates an early failure in the POST.
When both VIAs are in, I get just the pop sound as before. I swapped the two chips around with the same result. All other chips are in.
Even weirder, when both VIA's are in but I remove all RAM, I also get the death chime at startup.
I only get the pop sound rather than the death chime when both VIA's are in with RAM installed.
Regardless, with any configuration, I get the death chime with the NMI.
Very confused... also, it is the slow death chime which I believe indicates an early failure in the POST.
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Ah, this might be the issue. @techknight and @This Does Not Compute had an issue with a reloaded board using harvested VIA's - they're just standard, off the shelf, 65C22N chips, get them from either mouser or digikey.