Mac SE/30 logic board problem

[just.in.time]

Hi all,

I had an SE/30 board recapped by MacCaps.  Originally, board was no boot/no audio whatsoever.  It has made progress since being cleaned and recapped, audio now works.  However, I'm still left with this as a result:



The startup chime is messed up, you can hear it in the following Youtube video:

https://youtu.be/D_z18h5slp8

What has been done so far is the following:

*Tested with three different SE/30 ROMs (2 known good, and 1 from this specific unit)

*Tested with several different combinations of RAM.  Since in my possession after recapping I have personally tried 5Mb(4inA,1inB), 4Mb(4inA), and 1Mb(1inA), all with the same chime and image as above.

*Cleaned board several times

*Charles checked ~90 tracks by hand from the schematics, and all look good.

*I haven't bothered putting in a new PRAM battery yet, as that shouldn't affect the computer's ability to boot up.

Charles is thinking it could potentially be the RAM controller, if I'm understanding correctly.

Has anyone run into a similar (or the same issue) as this case?  If so, what fixed it for you?

I have at my disposal a mediocre soldering iron, some solder, and a very basic digital multimeter.  If anyone has simple instructions to follow along, I can probably swap some parts assuming my soldering skills (much like my soldering iron, they are mediocre at best) can keep up.

Here are some photos of the logic board:

 

[techfury90]

Your first problem was that you sent it to Charles.

 

[techfury90]

I don't know why he did that hackjob replacing those axial caps with radials that look like... that contraption. It's not only aesthetically ugly, it's poor workmanship. Why couldn't he just get the right kind or at least make the hack look nicer?

 

[Johnnya101]

Your first problem was that you sent it to Charles.

Where do we send boards to then?
For real, no idea...

 

[techfury90]

Wasn't there an entire thread on that where at least five people said they were either currently doing recaps or were willing to do them right after uniserver got banned?

 

[techfury90]

Hooboy, where to begin. I took a look at the photos carefully: all of the SMD electrolytics have been replaced with non-polarized ceramic caps. I also see that your SCSI and ADB fuses have been replaced with what look like MOVs (WTF?) instead of the proper fuse type. You need to demand that he put the proper components on the board, or pay someone more reputable to do it.

 

[TheWhiteFalcon]

You've been Uniservered.

 

[Johnnya101]

So then I SHOULDNT get my boards done by him then...

His website seems like he does a great job though... is he really that bad?

I have someone else that probably can. Anyone have the link to that other thread with the recap people??

 

[Unknown_K]

Looks like the guy used whatever he had laying around or could pick up cheaply. Audio circuits need the proper type of capacitor.

I think you will find there is a difference between doing recaps to help fellow collectors and doing it for a living where only profit is important.

 

[Johnnya101]

[snip]

Oops, meant to say looks like he does, not says! Of course it would say that!!!

Sorry to hijack this thread, but how hard is recapping? Ive read a few other threads on this, but really it seems like you get two pencil irons, heat up the solder, pull out the cap.. Put the new one in place and solder... profit????

 

[Scott Squires]

This is the first time I have actually seen a uniserver cap job. Glad I never sent anything to him. Sheesh.

 

[Unknown_K]

It depends on the board you are doing (how tightly spaced the parts are) and how much damage the leak has caused (corroded traces, solder pads that lift off no matter how careful you are, and chips that are dead).

Proper tools, a steady hand, and decent eyesight help.

Nothing hard about doing them other then time and effort. Troubleshooting a bad board on the other hand takes skill.

 

[techfury90]

Recapping requires some initial investment in soldering tools and supplies, but it balances out in the long run because once you've made that investment, each board you recap costs you under $10 in materials to do, give or take. Plus you can do it in under an hour and not have to send it off.

Edit: And by the long run, I mean after only about 2 or 3 boards compared to Charles' prices.

 

[Compgeke]

As others have said, that's a pretty bodged job. The startup chime you're hearing is the proper beep then right away chimes of death indicating the system's detected a problem.

My personal device would be to see if you can't either get him to fix it right or get someone else to do it. I'm not entirely sure what the thought process was here, even the axial caps could've been done better by laying them flat, bending a lead over, heatshrinking it then soldering it down, similar to http://i.imgur.com/DoosVJ5.jpg .

Anyway, here's the referenced thread where others said they'd be willing to help out. https://68kmla.org/forums/index.php?/topic/28590-if-you-are-desperate-for-recap/?hl=recap

As for self-recaps, you can get a decent enough chinese knockoff soldering station dirt cheap. A Yihua 8687D is what I got, $40 shipped from the US. For $5 more you can get an assortment of various tips for the iron on ebay and have far more flexibility.

 

[Johnnya101]

Gonna make a seperate thread on this or add to an old one containing this how to... Dont want to clog this up any more! Thanks guys, ill check this out for sure!

 

[360alaska]

Hooboy, where to begin. I took a look at the photos carefully: all of the SMD electrolytics have been replaced with non-polarized ceramic caps. I also see that your SCSI and ADB fuses have been replaced with what look like MOVs (WTF?) instead of the proper fuse type. You need to demand that he put the proper components on the board, or pay someone more reputable to do it.

Actually, your incorrect, those fuses are original! Here's another pic of a similar board found from google:



This is an older revision SE/30 Board! I've seen a few like that...

From the picture I looks like some of the removable chips may have come loose, i'd suggest removing and reseating them.

 

[Elfen]

Lets go to step 2: Getting it fixed.

Get a magnifying glass and look at the area above the SIMM Sockets. See if they have been rotted out. Fix what you can.

The board is almost there but it is one or two wires that have rotted part way and finally failed. Got to go through this with a fine tooth comb.

 

[just.in.time]

Just to clarify, this isn't intended to be a witch hunt of any kind, we can rest the pitch forks

He communicated to me beforehand that he was unable to get the board to boot correctly. This did not come back as a surprise to me. I've also had 2 other logic boards, a power supply, and an analog board all done by maccaps and have had them come back working.

I only mentioned him by name to drive home the point that the board was definitely washed properly and the symptoms are highly unlikely the result of left over cap goo. I imagine he has quite the board wash procedure down at this point seeing as he does this process a lot.

Moving on to specific details:
techfury90: what do you mean in regards to axial caps vs radial caps?
Is the SMD electrolytic being replaced by non-polarized ceramic caps a bad thing? My understanding is that ceramic caps have the benefit of not leaking in the future.
In regards to the fuses, what are MOVs? Would there have been any pros to using them over the original fuses?
I'm more of a software guy than an electrical engineer, so I'm trying my best to understand all this. Would you be able to mark up one of the photos above to label everything you have mentioned? I'd really appreciate it.

Unknown_K: you mention the audio circuits needing the proper type of capacitor. Are the particular capacitors used not the correct type? If they aren't, could they be causing the symptoms I'm seeing? I understand that issues with the Sony audio chip can sometimes cause system wide symptoms. I'm wondering if this is related?

Everyone else in general: any specific areas that I should be looking at to get this board back to life?

 

[just.in.time]

Get a magnifying glass and look at the area above the SIMM Sockets. See if they have been rotted out. Fix what you can.

Hi Elfen:  Say I am able to find a rotted out trace.  How do I repair it?  Small wire from where the trace started to where the trace ends, bypassing the trace completely?  Or do I make the repair right at the damaged spot? Thanks.