Rusty Macintosh SE/30

[Franklinstein]

Franklin, I didn't think of that, good point. That would certainly kill the HDD judging from the rest of the case.

I might take you up on that, I'll see what I have. I have two or three spare drives, though I think most are 800k, but the issue is, while I can swap parts, I cannot align them, I don't have the tools or knowledge, so their usability for parts is a bit limited.

If you can find a copy of "The Dead Mac Scrolls", by Larry Pina, at your local library (or on Amazon, if you want to keep a copy), you should pick it up. Inside is a step-by-step procedure for repairing and realigning Sony auto-inject floppy drives that I've used on multiple occasions. The tools you'll need are listed within but it's something like a #0-ish Phillips bit for most screws and a 1.5-ish hex bit for adjusting the stepper motor, both of which are typically included in those multi-bit driver sets. You'll need another Mac and/or a really long floppy cable to do this: you have to do the adjustments on a working system and it would be a huge pain to install and remove the drive every time you have to tweak it.

This book will also have procedures for checking and/or adjusting power supply voltages and may have a section that addresses your specific screen problem, among many other subjects (it's a really good resource). I'd look for you but my copy is apparently in storage.

 

[Jinnai]

That book looks incredible. Thanks for telling me about it; I go through a lot of Macs! Already ordered a copy. Although, I wonder how many of the parts it mentions are still available.

 

[dochilli]

Looks like a problem with the ROM. Do you hear a chime? If not, some traces from the ROM are probably rotten. Then you have to check continuity of these traces. You need the SE/30 schematics. https://museo.freaknet.org/gallery/apple/stuff/mac/andreas.kann/schemat.html

Did you clean the ROM socket and the ROM contacts?

Another problem can be UE8 or the multiplexers (UI, UJ F258). But if the mulitplexers are the problem, then you often get a chime of death.

Look for corrosion and rotten traces! Perhaps you can give us a photo of the board in high resolution?

 

[Jinnai]

Hey sorry for the late response! Thanksgiving kept me busy for a bit there. Although Thanksgiving break was what gave me time to work on this; now I have to go back to school so I'll have less time.

I'll take a look at the schematic. Hopefully I can understand part of it. I did clean the ROM socket and contacts. This motherboard was in very poor condition before, so I'll have to look closer for rotten traces. I had a pic of the motherboard before, but I don't know where it went. I replaced the caps. I wish I could try replacing the multiplexors, but it has never given a chime of death, either the normal one but distorted, or none at all... I'll try to get a pic of the board, but my phone camera is rather scratched up and blurry.

I must say, it's sometimes booting, but when it does, while it works, the boot chime sounds distorted, kind of grindy. In the OS, some sounds sound normal, but the more plain beep sound sounds a little like that, though not as much.

The CRT neck board still has some issues with rescan lines. The problem is not the analog board, so I'll try replacing some other things on the board, since I already replaced the transistor.

The PSU is also not working - I'm currently testing with one from an SE. It's showing between about 0.8 and 2 volts on my multimeter, so it's operating, but the voltages are far too low. Any ideas on that?

In positive news... here is the frame!

Before:

After:

 

[LaPorta]

You did a great job on that!

 

[metta]

VERY satisfying to see that - wow!

 

[Jinnai]

Thanks! It does look pretty nice. Although it is a lot easier than troubleshooting power supplies  For reference, it was about 8 hours in a wastebasket of vinegar, then washed and dried, then sanded with a sanding sponge.

 

[dochilli]

Perhaps the power supply needs a recap.

Not Sony: http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/2015/6/1_Macintosh_SE_30_PSU_not_SONY.html

Sony:http://www.maccaps.com/MacCaps/Capacitor_Reference/Entries/2014/10/9_Macintosh_SE_30_Sony_PSU.html
 

I had a Sony and replaced one of the large caps with a snap-in-capacitor because I could not get another replacement. The height of the caps is a problem. You have to order the right heights or you can get problems with the case of the psu!

 

[Jinnai]

I finally got all the capacitors in (except the three largest) and immediately replaced them all. That had no effect. I made a separate topic for discussing the PSU repair. If I could just get it running I'd be well on my way to having it running.

 

[CC_333]

I have some extra SE/SE30 PSUs available, if you're interested.

c

 

[Jinnai]

If you happen to have the Sony CR-44 one I think I would like one, so I can trade components and try to understand it in absence of an oscilloscope, unless you think that's a bad idea. I really am trying to understand power supplies by googling, but it's been difficult. 

I should mention though that there is a possibility that I'll sell this unit if I fix it, if that matters to you. 

 

[Jinnai]

I worked on the power supply for a while, but couldn't find anything useful without an oscilloscope. Something is wrong in the area of the switching circuitry. So I'll put off that for now. I got a spare PSU from CC, though its not the Sony one, so it wouldn't help me understand the one I have any more than my schematic.

I finally found the issue on the CRT board that was causing issues - CR2. The problems I were having were slight but numerous - occasional flickering, black smearing horizontally to varying degrees, and a slightly more noticable than usual retrace line. My meter stated that it was passing through about 1.4v instead of the usual 0.6v, so I replaced it and the issues went away. I think it may have been damaged by my killer CRT that took out Q1 and C5 as well.

Now I have to ask, where might I find a replacement for CR2? I swapped in one from my SE CRT board, so I'm not sure what value to look for, or how one diode can differ from another. From what I understand, it's a question of what operating conditions it is rated for, and whether its a PN, zener, or other type of diode. This one reads, all on separate lines; R, IN, 41, 50. It looks like it's just gold with a black band.

Yesterday I found why I was having boot issues - there was one bad stick of ram out of 8 1mb modules, difficult to catch because I'd only use 4 when testing. So I found it and swapped it out for a different one, and now all 8mb are working fine.

The sound issue appears to be a bad speaker. I can take it apart and see what I think, but I don't know about repairing speakers. A quick ebay search didn't turn up any great results for 2.25" speakers either.
 

 

[CC_333]

I have spare SE/30 speakers!

PM me if you want one. 

c

 

[Jinnai]

Oh man, if only I had known when you shipped the PSU! But I thought for sure the issue would end up being in the ASC/capacitor area.

An issue it is now having is rather bizarre - you kind of need a picture to see it:

This SE/30:

My working Classic II:

Closeup of the dim "eroded" pixels in text:

Some pixels are dim. I'm never heard of anything like it. I really want to get a new diode so I can verify that this is actually associated with the CRT board. At first I was just going to just leave it as it is, cause its far less distracting than the problem it had before, but it gets annoying if you actually try to use the computer for a while. It affects text and small images - the checkered background and screensavers look flawless - which made me wonder if the issue was somehow ROM related, but I don't think I had this issue with a known good CRT board. I'll need to get a diode to find out, or swap back in the diode I had taken from the good one. 

 

[Jinnai]

So school has begun and I'm getting busier. I fixed what I could, and what I couldn't I swapped in from a spare SE I have.

I was lucky that the motherboard worked. Other than that I had a spare CRT on hand that I added in and that was most of it. I have yet to fix some bugs on the analog board and CRT retrace circuit, but thats about it - the HDD and FDD are toast, and the PSU is likely toast without an oscilloscope to probe it further, I got as far as seeing that there was something wrong with the PWM circuitry. So those are swapped in from the SE. Got a new HDD and a nice big 2GB partition. Found some RAM on eBay for $16, bringing the total up to 20MB. Here it is running After Dark Star Trek:

Pic of the inside with it's new HDD (which needed an adapter, but I must say it works very well) and it's snazzy pink sled:

Next I will replace the case with a clear one from MacEffects once it comes out!

 

[Johnnya101]

Wow. Thats pretty weird. Ive got a somewhat working Sony PSU from my SE/30 if you need one to swap stuff with. It has a video jitter sometimes when cold, otherwise working and recapped. Tech says transistor. If you need it, PM me and we can work something out.