SE/30 Reloaded Board - First Test

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Steve Rieck

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UPDATED: Current Situation 8/22/25
  • Horizontal Bars (TI VRAM chip equivalent of Simasimac).
  • No startup chime happy or sad. Just a speaker pop sound at startup.
  • Reset button works.
  • Interrupt (NMI) button produces a distorted Sad Mac Chime (video link below).
  • Known good - ROM, RAM, VROM, VRAM, PALS Tested in a working SE/30.
  • All Address and Data lines tested OK.
Thanks for any ideas!

IMG_5580.JPG


Dropbox

www.dropbox.com www.dropbox.com
 
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robin-fo

robin-fo

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This is something I also had to go through with my first Reloaded board. I was in the same situation… It turned out to be a short of the main clock signal and ground at the FPU socket.
 
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Steve Rieck

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robin-fo said:
This is something I also had to go through with my first Reloaded board. I was in the same situation… It turned out to be a short of the main clock signal and ground at the FPU socket.
Click to expand...
Thanks for letting me know. In this case, pins 4 and 11 are not shorted on the FPU. Maybe the clock signal is shorted somewhere else.
 
robin-fo

robin-fo

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In my case, it (pin 11) was shorted to pin 10 or pin 12. But it would really have surprised me if be both did the same mistake…

Do you have a scope to probe the signals?
 

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Steve Rieck

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robin-fo said:
In my case, it (pin 11) was shorted to pin 10 or pin 12. But it would really have surprised me if be both did the same mistake…

Do you have a scope to probe the signals?
Click to expand...
Yeah, the FPU socket was installed on the board at the PCB factory so I'm pretty sure the FPU is ok. Gonna swap out the Video ROM and Video PALS tonight and see if anything happens...but unfortunately, I think the GLU just didn't survive the other board.
 
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Steve Rieck

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robin-fo said:
That‘s just one of many, many possible causes :/
Click to expand...

robin-fo said:
That‘s just one of many, many possible causes :/
Click to expand...
True. I need to think more positively but it was rough when it came off the board. Definitely a "wonder if it made it" situation. Surprisingly, all the pins were intact and cleaned up very well so I was being optimistic about it since it will be expensive/tricky to find another. The main reason I put in a socket for it.
 

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robin-fo

robin-fo

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Where are you located? Maybe there is someone nearby with a known working, socketed board where you could test your GLUE?

When my board is not working, I often put it aside for some time and come back to it later. It took me months to get my first board working!
 
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Steve Rieck

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Yeah, I'm in Atlanta, I've got two other SE/30's but of course the GLU's aren't socketed and I'm not gonna mess those up for this after I restored them. I definitely plan to keep this as a project. Enjoying figuring it out and I've learned alot in this process.
 
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Steve Rieck

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This Does Not Compute said:
If this is one of the boards from the group buy I ran, you need to replace the diodes on the bottom side (near the RAM slots) as the parts were populated wrong at the factory. I mailed out replacements to everyone in the group buy.
Click to expand...
Right. I saw that in your video. The seller I got it from assured me that he had replaced those diodes. But I will verify. Thanks.
 
wottle

wottle

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This Does Not Compute said:
If this is one of the boards from the group buy I ran, you need to replace the diodes on the bottom side (near the RAM slots) as the parts were populated wrong at the factory. I mailed out replacements to everyone in the group buy.
Click to expand...
Yeah, that was the spare board I got from your buy. I did do the diode replacement with the ones you sent after the fact. I didn't run into the horizontal bar issue with the other board, but may be worth double checking those. I did notice some not thoroughly cleaned flux on the diodes that I thought confirmed my memory that I had replaced them, but may be worth swapping them out just in case.

I usually keep pretty good notes on my machines, but I didn't have the reloaded board in my inventory app, so I didn't have the detailed history of work on it. Hopefully we can figure out what is going on. I know from my reloaded build, I would really take a good extra look or two at any soldered on PLCC Chips, I definitely had some pins not connected and some that were shorted to a nearby pin.
 
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Steve Rieck

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wottle said:
Yeah, that was the spare board I got from your buy. I did do the diode replacement with the ones you sent after the fact. I didn't run into the horizontal bar issue with the other board, but may be worth double checking those. I did notice some not thoroughly cleaned flux on the diodes that I thought confirmed my memory that I had replaced them, but may be worth swapping them out just in case.

I usually keep pretty good notes on my machines, but I didn't have the reloaded board in my inventory app, so I didn't have the detailed history of work on it. Hopefully we can figure out what is going on. I know from my reloaded build, I would really take a good extra look or two at any soldered on PLCC Chips, I definitely had some pins not connected and some that were shorted to a nearby pin.
Click to expand...
Thanks. I think the wrong parts were transistors rather than diodes so I should be able to at least test which I've got on the back of this board with a meter.

Are you saying the exact symptom of this issue is the horizontal bars I'm seeing? That would be encouraging news, if so.

Definitely checked for continuity to where all the pins go and no bridges on all the PLCC soldering a few times so I feel good about that.
 
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wottle

wottle

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Steve Rieck said:
Thanks. I think the wrong parts were transistors rather than diodes so I should be able to at least test which I've got on the back of this board with a meter.

Are you saying the exact symptom of this issue is the horizontal bars I'm seeing? That would be encouraging news, if so.

Definitely checked for continuity to where all the pins go and no bridges on all the PLCC soldering a few times so I feel good about that.
Click to expand...
Sorry, I don’t know the symptoms of the incorrect diodes. I replaced mine before I transported anything.

I think Colin was saying you’d get a Simasimac (which I always thought was different than horizontal bars, but others can chime in if that is a type of Simasimac). So I think it may be something different
 
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Steve Rieck

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wottle said:
Sorry, I don’t know the symptoms of the incorrect diodes. I replaced mine before I transported anything.

I think Colin was saying you’d get a Simasimac (which I always thought was different than horizontal bars, but others can chime in if that is a type of Simasimac). So I think it may be something different
Click to expand...
I think both horizontal bars and simasimac are just the default output of the VRAM chips ...and those would be for the Texas instruments chips and the NEC chips respectively. The ones currently in my board are Texas instruments so in this case, I get horizontal bars rather than simasimac....I have some NEC chips from the bombed board so I'll try to verify that theory tomorrow. If correct, I would get a simsimac rather than horizontal lines with NEC's.
 
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