Mac SE/30 with Simasimac display - Page 1
Forum section: electronics / repair

author: edy
author_rank: Super Contributor
timestamp: June 13, 2022, 03:34:05 pm
content: Hi everyone,I pulled out my Mac SE/30 from storage at my parents... Haven't powered it up for almost 15 years. The machine is circa 1989-1991. Turned it on, I can hear the hard drive whirring away, screen on, fan spins. Power seems good but I'm getting what appears to be a common issue on these machines, the dreaded "simasimac" screen:Thankfully it seems this issue is not unusual and there have been many posts on how to start fixing it. I wanted to share this here on the forum to see if anyone has any other advice that could help. From what I've gathered from the various other postings on this problem (just Google "simasimac") I will need to do the following:1. take out all RAM/ROM/SIMMS that I can remove and check contacts to make sure they are clean- is there a contact cleaner I should be using? Am I looking for anything in particular?2. check all the caps on the board for signs of leakage or corrosion to copper traces3. replace on-board battery4. trace paths from main processor to glue chip, and others to make sure all traces have continuitySome posts have even suggested throwing the main board into a dishwasher to clean it! I'd rather go over it with 99% isopropanol and a Q-tip first before doing that and checking all traces. I'm NOT a fan of putting the board through the dishwasher (and then toaster ovening it)... way too much can go wrong!A few encouraging points:1. I'm glad to see the machine power up, doesn't seem to have any power issues.2. Screen/CRT is good3. Hard drive sounds like it is trying to load something4. "Simasimac" (which is a play on Japanese words zebra-striping or simasima) seems to be a common problem with many people having seemingly resolved it by the above stepsThanks and any advice would be greatly appreciated!

author: edy
author_rank: Super Contributor
timestamp: June 13, 2022, 05:52:32 pm
content: ...Just forgot to mention:Any advice on alternatives to using surface mount tantalum capacitors? According to this site (https://recapamac.com.au/macintosh-se-30) the list of caps needed to recap the board are:1µf 50V KEMET tantalum capacitors (T491C105K050AT) (need 1 of these)47µf 16V KEMET tantalum capacitors (T491D476K016AT) (need about 10 of them)220µf 16V Vishay axial capacitors (MAL213825221E3) (need 1 of these)470µf 16V Vishay axial capacitors (MAL211835471E3) (need 1 of these)I am not sure how easy it is to replace surface mount caps as I am using just a soldering iron (I don't have a hot air gun). Usually if some of the pads can be seen I can get down in there with a fine tip but sometimes the component almost completely covers the pads and you almost have to heat them up so they "settle down" into the molten solder themselves. I can buy tantalum "pearls" (the kind for PCB through-hole mounting) but they are kind of expensive at my local shop ($3 a pop!). So what is the cheapest way to buy these in Canada? Any advice would be appreciated. I also don't have many options for axial capacitors at my local Sayal.com, just radial. I could try to "bodge" one in but if I'm already going to have to purchase SMD Taltalums from somewhere then I may as well get the proper axial caps from the same source.Thanks for any help!

author: james_s
author_rank: Super Contributor
timestamp: June 14, 2022, 04:50:28 am
content: Have you opened it up yet? The most common problem when the get stored for a long time like that is the PRAM battery leaks and completely destroys the inside of the computer. Make sure that hasn't happened before you go too far trying to come up with a repair plan.Replacing the capacitors with a soldering iron is trivial. Grip each of the original parts with pliers, push down firmly and twist, it will twist right off the board and then you can use a soldering iron to wipe the remains of the leads off the pads. I've re-capped dozens of 68k Macs with this technique and I haven't damaged a pad since learning this trick.

author: Peacefrog
author_rank: Contributor
timestamp: June 14, 2022, 06:22:50 am
content: Yeah, the first step here is to pull out the board *then* see where you're up to between battery and capacitor leakage. If you avoid the former (fingers crossed!), you might be able to get the machine booting without a recap, but you'll need one long term. You only need to start following traces if you can't get it to boot.The screen below can also be caused by bad/improperly seated RAM (although you'd get a chime, generally), so the TLDR would be:- Pull out the board and inspect (post images to this thread!)- If you've escaped major leakage, reseat the RAM chips and retry booting- If there's minor cap leakage, you might be able to coax the board back into life temporarily by scrubbing around the caps with isopropyl alcoholIf that fails (or the leakage is bad), it's time to look further. Note that it's also possible to buy an ATX extender and chop off the unused pins to avoid constantly having to pull and re-insert the PCB. Oh, and be careful around the CRT, especially just after switching off!

author: edy
author_rank: Super Contributor
timestamp: June 23, 2022, 11:50:55 pm
content: Ok I’ve had some time to make a little progress. I’ve removed the board and taken photos so the next few posts will be of the motherboard. It isn’t looking too bad but needs a cleaning and I believe I’m going to recap the entire board, that seems to be the main issue. I’ll also need a new PRAM battery… some people suggested I switch the holder to a CR3032 and use that as it’s easier to obtain? Not sure if it’s worth the bother. I can operate the machine without a battery I assume it just won’t retain certain settings but before I do anything the recap alone and cleaning should hopefully resolve the Simasimac issue and at least let me boot? Then I can figure out the battery.First few pictures of the board… I have some questions about the caps and also the bridge wire on the back. Doesn’t look like the same brand caps on other Mac SE/30 boards I’ve seen online and videos?!?

author: edy
author_rank: Super Contributor
timestamp: June 23, 2022, 11:52:46 pm
content: I can only attach 3 photos at a time as I’m trying to keep them high resolution but still under 5MB per-post limit. You can see some corrosion and dust on the IC pins but they are not too bad I think. After washing this should look better.

author: edy
author_rank: Super Contributor
timestamp: June 23, 2022, 11:55:49 pm
content: Some more close-up shots.You can see the battery, I’m assuming I don’t need a new battery to solve the boot up… I can get one later right? I’ll need axial caps also as it may be hard to get long enough pins on a radial cap to replace the 2 axial caps on the board.

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 23, 2022, 11:58:35 pm
content: The board doesn't look too bad for its age.As james said, replacing the capacitors is not difficult with a soldering iron. The pads are extending enough to make the job rather easy here. Just use a desoldering wick to suck the solder off for desoldering the caps. It will help tremendously.And yes, as I've often heard, the most common cause for this boot issue is dead caps and/or faulty RAM. After recaping, also try cleaning the RAM slots and reseating the RAM sticks.Operating the machine without the battery will be very annoying. I don't recommend that. I don't think it will prevent the Mac from booting up though, but I can't guarantee that.

author: edy
author_rank: Super Contributor
timestamp: June 24, 2022, 12:00:18 am
content: Here you can see a bunch of photos of the SMD caps. They are electrolytic polarized? They don’t look like others I’ve seen on Mac board as they have no writing on the top and they have this yellow gold band around them instead, with a black mark on the band on the side to indicate polarity. I don’t think this machine was recapped… I obtained the machine many years ago in high school (early 90’s) so this must have been from the factory?!? Just a different supplier for that run?

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 24, 2022, 12:04:09 am
content: I suppose you already ran into this, but here it is anyway:https://recapamac.com.au/macintosh-se-30/

author: edy
author_rank: Super Contributor
timestamp: June 24, 2022, 12:07:51 am
content: Last photos….Some more closeup showing some corrosion of IC pins, just some dust and dirt but hopefully will clean up nicely. Another photo showing empty battery holder.Finally, something I have not noticed on any other boards or mentioned is a bodge wire on the back looking like it connects pins on two IC’s. I haven’t yet investigated exactly which are connected and what pins, I will have to follow the schematics, and why that is the case. Again, I don’t think this machine has ever been repaired as it has been in my possession since the early 90’s and I’ve booted it at least a few times during 2001-2005 no problem. Since then I left it in my parents garage and only recently dug it out and it powers on no problem.At this point I need to find a supplier for axial caps and those SMD caps. I found some links on eBay for assorted caps. I need a 50V cap and the rest are all 16V. Any suggestions where I can more easily buy stuff in Canada? My local electronics component store (Sayal.com) has no SMD electrolytics and no axial caps available in store. Anyone have good experience ordering online for a small order like mine?Thanks again for all your help and suggestions.Note: I’ve added a link (see below) from Hackaday so I remember later if I need to check any traces that run under caps in case I run into same problem… but the existing bodge wire on my board doesn’t seem to be related to caps and I can’t understand how it got there because as I mentioned my Mac as far as I know was fairly “new” when I acquired it…https://hackaday.com/2020/11/01/bodge-wire-saves-a-vintage-mac-se-30-from-the-heap/

author: SiliconWizard
author_rank: Super Contributor
timestamp: June 24, 2022, 12:13:20 am
content: The battery looks like a CR123 format? It's definitely still easily available, so I'd suggest buying a new one rather than bothering with changing the holder.Ordering in small quantities like this will be no problem using Mouser, for instance. Of course, for small orders, the unit price of the components and the shipping fees will be a bit high.

author: james_s
author_rank: Super Contributor
timestamp: June 24, 2022, 06:26:04 am
content: Those Tadiran batteries are pretty good, I don't think I've had one leak yet. Maxell also made a lot of batteries in that style and those are notorious for leaking and completely destroying the computer, I think they release hydrochloric acid vapor.The round things with the gold bands are indeed SMT electrolytic capacitors and all of them need to be replaced. It sounds a bit crazy but trust me on this, grip each capacitor firmly with pliers, don't worry if you squish it a bit since you're replacing it anyway. Push down firmly while holding it and twist and it will snap clean off. Pick away any bits of the plastic base that remain and then use a soldering iron to wipe the remains of each lead off the pad. Once it's removed, clean thoroughly, I like to use isopropyl on a bit of magic eraser.

author: tooki
author_rank: Super Contributor
timestamp: June 24, 2022, 11:00:37 am
content: Quote from: edy on June 23, 2022, 11:50:55 pmQuote from: SiliconWizard on June 23, 2022, 11:58:35 pmMany vintage Mac models will not boot at all without a working PRAM battery. (As a teen I briefly worked at a gray-market Apple reseller who, when a non-booting Mac would come in for repair that was just due to a PRAM battery, would fix it in 5 minutes with a $5 battery but then charge the customer an hour or two for “logic board repair”.) I don’t know for certain whether the SE30 is one of these models, but I suspect it is.Quote from: SiliconWizard on June 24, 2022, 12:13:20 amIt’s not a CR123 (3V lithium manganese dioxide). It’s a 1/2AA 3.6V lithium thionyl chloride cell.

author: james_s
author_rank: Super Contributor
timestamp: June 24, 2022, 05:25:32 pm
content: Quote from: tooki on June 24, 2022, 11:00:37 amThe SE/30 will boot without a battery. The Mac II and possibly a few others in that range have two batteries and won't boot without at least one of them. I've never seen a schematic but I suspect they did not have a standby PSU so they require a battery to power the soft-power circuit. All of the B&W compact Macs have a conventional hard power switch.

author: BrokenYugo
author_rank: Super Contributor
timestamp: June 24, 2022, 07:50:43 pm
content: Close up pics looks like capacitor leakage to me, you probably caught it in time though.

author: tooki
author_rank: Super Contributor
timestamp: June 25, 2022, 01:30:13 am
content: Quote from: james_s on June 24, 2022, 05:25:32 pmIt’s got nothing to do with standby power. On models that require a good PRAM battery to boot, they turn on but do not even try to boot, staying at a black screen. I know it affected both models with soft power and hard power switches. It’s just been so long that I don’t remember which models they were (it was a lot).

author: james_s
author_rank: Super Contributor
timestamp: June 25, 2022, 05:38:28 pm
content: Quote from: tooki on June 25, 2022, 01:30:13 amI'm quite sure I've booted my SE/30 without a battery, although it's a bit annoying to not have one as the screen brightness setting and time of day and whatnot aren't stored.The Mac II has two batteries and without one of them it won't even power on, the battery is used in the soft power circuit on those. The IIfx is another one, and I think the IIcx is also. Later machines switched to only having one battery.

author: tooki
author_rank: Super Contributor
timestamp: June 25, 2022, 06:50:17 pm
content: Quote from: james_s on June 25, 2022, 05:38:28 pmCould be, it might not be one of the affected models. As I said, I’m not sure which models exactly are affected.Quote from: james_s on June 25, 2022, 05:38:28 pmYeah, here’s the IIx power circuit:https://www.downtowndougbrown.com/2015/03/explanation-of-the-macintosh-iiiix-power-onoff-circuit/Regardless, though, what I was talking about is models that won’t boot without a PRAM battery. The second battery those models needed to boot wasn’t the PRAM battery (though it was the same type of cell). As I said, some models (like some LC models) simply won’t POST without a PRAM battery. They power on, but nothing happens.

author: james_s
author_rank: Super Contributor
timestamp: June 25, 2022, 10:07:49 pm
content: Cool, I hadn't seen a schematic of the circuit before, nice find.

author: edy
author_rank: Super Contributor
timestamp: June 26, 2022, 05:26:26 pm
content: I’ve removed all the SMD caps and the 2 axial caps. I’ve attached a few photos and yes you can see the leakage under especially that last photo showing C13. There are still legs soldered on the pads, I went over all of that with a soldering iron and cleaned off all of the remnants and now down to clean pads.In that last photo when I removed C13 I bent Q3 and it lifted a pad off. I’ll show you in the next post photos of the result and how I managed to fix it. Q3 looked a bit corroded anyways but now I need to find a replacement for that as well (see next post).

author: edy
author_rank: Super Contributor
timestamp: June 26, 2022, 05:36:57 pm
content: Ok so next to C13 I pressed on Q3 and the top lifted off, not sure if it was already weak but in any case the pad lifted off the board (the top single pad) while the bottom which has 2 pads stayed attached. I tried to see if I could reattach but it was pretty much a lost cause…. Q3 had to be sacrificed.The second photo shows the “dog barf” appearance of the area during cleaning, I think it was corrosion, solder residue, flux and other garbage that ended up mixing there as I tried to get the area heated up and maybe salvage the Q3 part but it wasn’t going well so at that point I decided to just clean it all off.The third picture after cleaning it up, getting the bottom 2 pads cleaned up and removing whatever garbage I had in the 2nd photo. I needed to figure out how to get the top pad of Q3 usable and noticed it went to that through-hole via which connected to the underside of the board with a trace running to a resistor. So I found a thin piece of metal wire (like the lead off a resistor) and passed it through the hole/via and made sure it was soldered on the back side and continuity to the resistor. I bend the metal wire on the front side to make a substitute “pad” to solder to when I can get a replacement for Q3.The fourth picture shows the result of this bent wire. I checked all continuity of the Q3 pads… top one goes to a resistor on the underside of the board (as I mentioned) and one of the bottom ones goes to another resistor, and the second bottom pad is connected to what I believe is ground.

author: edy
author_rank: Super Contributor
timestamp: June 26, 2022, 05:46:28 pm
content: Ok so I confirmed from the schematics indeed that transistor is connected to the 2 resistors and ground which I confirmed continuity with my crappy repair job. Now to find that component or something similar to it that I will be able to actually solder properly! Is it 2N3904 or 2N3984? I found an answer in Reddit link so I guess this is it…. (Note same issue falling off due to corrosion):https://www.reddit.com/r/VintageApple/comments/ct796w/macintosh_se30_q3_transistor/

author: tooki
author_rank: Super Contributor
timestamp: June 26, 2022, 08:38:11 pm
content: Quote from: edy on June 26, 2022, 05:46:28 pmClearly a 2N3904, based on other 0’s and 8’s on the page. The 8 is significantly wider than the very narrow number 0 (which itself is significantly narrower than the letter O, precisely so they can be told apart).

author: edy
author_rank: Super Contributor
timestamp: June 26, 2022, 09:10:29 pm
content: Yes thank you, I also found this page which redraws all of the schematics in much clearer way!https://github.com/mishimasensei/macse30mlb/blob/master/hardware/pcb/mlb/output/Macintosh%20SE:30%20Schematic%20Redraw%20of%20050-0253-01%20JUN-19-2022.pdfI’m going to put an order in for both mouser and digikey and see what they come up as cost wise including shipping. Do I go for Tantalum caps? A video from Adrian’s Digital Basement (YouTube channel) suggested using these. He also switched the 3.6V battery to use a CR2032 coin battery which is easier to source even though it’s 3V instead of 3.6V he said it makes no difference. I watched a few of his videos and it seems there are all sorts of issues that come up sometimes trying to track breaks with traces and continuity that create strange problems… looks like it will be a long hunt sometimes and bodge wires needed!