SE/30 shows Simasi-like pattern when a PDS card is installed

[Boctor]

About a year ago, I cleaned an SE/30 motherboard and recapped it with tantalum capacitors. It has been working normally since then, except for one of the axial capacitors, which was not properly soldered. I got bus errors and sad macs recently, but solved them all by re-soldering the bad joints.

However, problems happen if a PDS card is inserted. In specific, I tried a RasterOps Color Board 264/SE30 and an Asante MacCon 30ie. More confusingly, there was a brief time when the Color Board was working perfectly, but later it began causing the Simasi pattern with the vertical lines. This was the same pattern that I saw when the capacitors went bad, and it is never accompanied by a boot chime of any kind. After a PDS card causes the SE/30 to do this, it still won't start up again, even when the card is removed. What I needed to do was actually remove and reinsert the PRAM battery.

Does anyone know what could be wrong with my PDS slot? Are there any specific capacitors involved that could be messing with it? Thanks for your time, and I apologize if this is a common issue or has been asked before; I couldn't find anything similar with searches.

 

[Johnnya101]

Is it a card that needs a driver or anything installed? Sometimes weird stuff will happen without installing it.

Other than that, I'm gonna say wait for the pros but bad traces or chips or something could be the culprit.

 

[Boctor]

Is it a card that needs a driver or anything installed? Sometimes weird stuff will happen without installing it.

Other than that, I'm gonna say wait for the pros but bad traces or chips or something could be the culprit.

About the drivers, yes and no. The Color Board used to work without one, and any manuals I've read say it's not required. The Asante card does use a driver, which I have not yet installed. I am new to PDS installations, and I should have thought of this. However, I don't know why a card with no driver would prevent the machine from booting at all.

 

[EvieSigma]

Check for a poor pin connection. I had issues with an Ethernet card until I fixed one of the pins.

 

[Boctor]

Check for a poor pin connection. I had issues with an Ethernet card until I fixed one of the pins.

Is there a certain method for cleaning the contacts in my logic board's PDS slot? I am not sure how much dirt could be inside the pin holes, now that you mention it. Then again, I don't know of a way to peer inside. All of the pins on the cards themselves look clean and stand straight.

 

[joethezombie]

First thing to check is for proper voltage on the +5 line. Check it from the floppy port without a PDS card installed. Then check it with a PDS card installed. Before I recapped my power supply, a PDS card would pull the line down to 4.2v and I would get simasimac.

 

[mrpippy]

It's a long shot, but does your board have a socketed CPU? If so, might be worth a try to reseat the CPU. My recapped SE/30 would reset regularly until I reseated the CPU.

 

[Boctor]

It's a long shot, but does your board have a socketed CPU? If so, might be worth a try to reseat the CPU. My recapped SE/30 would reset regularly until I reseated the CPU.

My board is the model with the CPU attached, so I don't think it applies. I should have been more specific about it in the first post. When inspecting the board, I have never noticed any bad traces.

First thing to check is for proper voltage on the +5 line. Check it from the floppy port without a PDS card installed. Then check it with a PDS card installed. Before I recapped my power supply, a PDS card would pull the line down to 4.2v and I would get simasimac.

I'm not sure if the power supply is the culprit, since it was replaced around 2 years ago. Of course, the part itself was already very old, so I will definitely follow your advice on this. It could very well be be the issue.

 

[Boctor]

I'm sorry to reply to my own post again, I could not find an edit button. I tested the 5V on my SE/30's SCSI power connector, and it appears to dwindle a bit after power on, even if the PDS slot is empty. The machine doesn't seem to react when it's dancing around 4.8V. But once the PDS card is inside, the voltages only get worse. In fact, it succeeded in booting once with the Asante Ethernet card inside, but then failed on every other attempt, because the voltage was getting visibly lower. I'm beginning to think joethezombie's post is correct; this type of inconsistent behavior was happening to my logic board when it had bad caps.

This is my only compact Mac, so I don't know if the slight fluctuations in voltage are normal, but I'm guessing not. Thanks to everyone reading/posting for their time and diagnoses on this thing.

 

[joethezombie]

Well, I have noticed simasimac as a voltage related condition happens at voltages less than 4.6, depending on what PDS card I was trying to use.  What was the lowest voltage you measured?

It also turned out it wasn't a problem with my power supply, but rather the UE8 component.  You can read my thread about it over here:

https://68kmla.org/forums/index.php?/topic/29176-low-5v-line-from-recapped-se-power-supply/

 

[Boctor]

Well, I have noticed simasimac as a voltage related condition happens at voltages less than 4.6, depending on what PDS card I was trying to use.  What was the lowest voltage you measured?

It also turned out it wasn't a problem with my power supply, but rather the UE8 component.  You can read my thread about it over here:

https://68kmla.org/forums/index.php?/topic/29176-low-5v-line-from-recapped-se-power-supply/

I don't recall the readings ever getting that low. If I'm correct, UE8 is an IC? I have never attempted to replace one of those. I'll probably check if the one on my board heats up. Is there a technical reason for UE8 drawing so much power?

 

[joethezombie]

I was quite surprised, as UE8 is part of the video circuitry, and I was not having any issues at all with video.  But that chip was uncomfortably hot to the touch, and replacing it fixed my issue completely.  I would have never even thought to check it if not for the advice of tomlee59.  But, if you have voltages around 4.8, I think that's pretty nominal, and wouldn't think you have that particular issue.

 

[techknight]

UE8 is a common failure point now. Why it fails so often is yet to be determined. 

But these days its almost a staple to change it when recapping. 

 

[Boctor]

There is something afoul with my UE8. Not only that, but there are some very damaged traces that I failed to notice when inspecting the board before. Some of these are near the PDS slot, too, which is kind of a slap in the face. I guess they were somehow connected for a brief time in 2015, allowing me to use the RasterOps board a year ago. It seemed to work on and off, before eventually failing completely. Now that I think about it, the "for parts" SE/30 I took this board from was very neglected. Burnt tube, broken analog board, dead hard disk, jammed floppy drive. I should have expected this from the beginning, but at least the board helped me learn recapping.

Traces and ICs are far beyond my skill level, so I don't really have anything left to do with the SE/30 logic board. I downgraded the computer back to an SE, and the 5V lines are no longer fluctuating. Everyone has been very helpful about the PDS woes, and I'm grateful to have somewhere to ask about these things. Without all these pointers and tips, I would not have noticed the lingering issues from this SE/30's electrolyte-soaked life.

 

[Johnnya101]

Well, there's people here who can probably fix it if it isn't too bad.

 

[Trash80toHP_Mini]

Sounds like a great opportunity to learn how to patch a few traces and replace a chip to me.

Have you gt a continuity tester?

 

[Boctor]

Well, there's people here who can probably fix it if it isn't too bad.

I'm sure it's not more than 1 or 2 bad traces, if any. The slot somehow "magically" worked in 2015, when I cleaned up the board. There's also an IC with some corrosion on it that needs a serious cleaning. It's some green stuff stuck on the package itself, not really much on the pins.

I did the "soapy water" bath and dried it for several weeks in 2015, but I don't think this was good enough. Since then, I've mostly been using rubbing alcohol, cleaning things very gently. If I recall, there's another chemical that the entire board should be washed with? If this board is still functional at all, I'd like to make sure all of the corrosion is really gone.

Sounds like a great opportunity to learn how to patch a few traces and replace a chip to me.

Have you gt a continuity tester?

I believe the multimeter I used to check the 5V line has a continuity mode. If not, I can order one. Are there any models that work particularly well for this? I appreciate all the help.

 

[Johnnya101]

Well better than a rotted board!

Maybe last time when you cleaned it some parts never got neutralized and kept eating away or something?

 

[Boctor]

Well better than a rotted board!

Maybe last time when you cleaned it some parts never got neutralized and kept eating away or something?

That's probably right. Before I do anything more to the board, I'm going to need to clean it up and make sure nothing can deteriorate any further. Then I can worry about finding bad traces and UE8. What is the "de-facto" way to neutralize the corrosion in an SE/30? The last time I did it was with a Game Boy, so I doubt it's the same.

If it's drawing excessive power, does UE8 need to be replaced completely? I'm wondering where I'd need to order one. I'm sure these UE8 questions have been answered before, but I like to be certain of everything. Thanks.