SE/30 Reloaded Board - First Test

[Steve Rieck]

And.......Horizontal Bars. No Sound because I assume nothing is even getting to the ROM.
I believe this is the default output of the VRAM.
Let the fun begin.

• Swapped out known good ROM - No change
• Checked ROM Seating - No change
• Swapped out known good RAM - No change
• The Video ROM is a homemade flash.
• The Video PALs are from the bombed board. I have a set of flashed ones I could try.
• Tested all pins on the GLU (socketed) - All Ok
• The GLU Pins still may not be making good connections to the socket.
• The GLU chip could be damaged from corrosion or heat removing it.
• Continuity checked and OK on all PLCC Chips as well as the Video ROM and Video PALS. No Bridges/Shorts.
• All Address and Data Lines seem OK in terms of continuity around the board.
• The CPU is socketed - Bought on eBay. Looked pristine.
• Stole the RTC (3440042B) from a spare SE 800k board.
• Analog board has been fully recapped, reflowed solder and is 100% with other boards.
• No chips are getting hot or even warm.
• Reading 5v at several places around the board when it's on including the GLU, Video ROM and ROM. For example, 5v on pin 27 of the GLU as well as pin 12 of the ROM. Not sure if this is significant?

My first suspicion is the GLU but I'm fairly new to this so...

Thanks for any insight!

 

[robin-fo]

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.

 

[Steve Rieck]

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.

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]

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?

 

[Steve Rieck]

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?

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.

 

[robin-fo]

think the GLU just didn't survive the other board.

That‘s just one of many, many possible causes :/

 

[Steve Rieck]

That‘s just one of many, many possible causes :/

That‘s just one of many, many possible causes :/

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.

 

[robin-fo]

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!

 

[Steve Rieck]

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.

 

[robin-fo]

Btw. I wrote down the story of my board here:
https://tinkerdifferent.com/threads/wtd-se-30-reloaded.1817/post-15366

 

[Steve Rieck]

Btw. I wrote down the story of my board here:
https://tinkerdifferent.com/threads/wtd-se-30-reloaded.1817/post-15366

Cool. Thanks.

 

[This Does Not Compute]

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.

 

[Steve Rieck]

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.

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.

 

[Steve Rieck]

two things.

Replaced the 5 PAl Chips - No change

I noticed the reset button does work. Not sure if that is significant?

 

[wottle]

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.

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.

 

[Steve Rieck]

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.

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.

 

[wottle]

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.

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

 

[Steve Rieck]

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

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.