68kMLA Classic Interface
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| Advice with SE30 restoration | |
| Posted by: Spacerog on 2025-05-03 06:30:21 It was $20. And I have learned A LOT playing around with it. Also good to know that my RTC is not necessarily bad. (There was no bomb and all the traces tone good.) I am back to poking around in the UD8, UE8, UE10, C2, and C7 area. Debating with myself wether to put the original UDB and UE8 back in or wait for the Mac Peeker board I ordered to arrive. | |
| Posted by: djc6 on 2025-05-03 07:12:40 I’m mostly concerned about previous report that chips are hot, that something is shorted. When I run one of my SE/30s logic boards for a hour or so outside the chassis I can’t feel heat from any chips | |
| Posted by: zigzagjoe on 2025-05-03 14:20:13 It is normal for some of the chips to be warm on the SE/30 especially in open air without cooling. In particular the video PALs in the center will *always* be hot. Here's a series of thermal images. | |
Posted by: Chardonneret on 2025-05-04 00:07:16It is normal for some of the chips to be warm on the SE/30 especially in open air without cooling. In particular the video PALs in the center will *always* be hot. Here's a series of thermal images.Check if each chip is in the right place. There’s an ID on each chip. It matches where they have to be. I don’t have access to this file right now (away on a vacation), but you can find it on the internet. It indicates where each PAL is located. | |
| Posted by: zigzagjoe on 2025-05-04 02:23:17 Ah, I'm not the OP. Those reference pics are a working board in open still air, fully heat soaked. | |
Posted by: djc6 on 2025-05-04 09:47:03It is normal for some of the chips to be warm on the SE/30 especially in open air without cooling. In particular the video PALs in the center will *always* be hot. You are right - I let one of my boards run for a few hours and the PALs are quite hot to the touch. Do they need little heat sinks? I don't think I've read many or any posts about the PALs failing. | |
Posted by: zigzagjoe on 2025-05-04 10:34:58You are right - I let one of my boards run for a few hours and the PALs are quite hot to the touch. Do they need little heat sinks? I don't think I've read many or any posts about the PALs failing.Nah, they're perfectly happy to operate at that temperature forever. They're rated north of 100 deg C, IIRC. | |
| Posted by: Spacerog on 2025-05-05 10:40:15 I an effort to track down this short I am rechecking every part of the board I have touched for probably the fifth time. I was suspecting a bad new UD8 and UE8 but removing them makes no difference, no raster, no bong, hot chips. This is going to take a while. | |
Posted by: djc6 on 2025-05-05 10:48:21I an effort to track down this short I am rechecking every part of the board I have touched for probably the fifth time. is it possible something is shorted under the capacitors? Similar to what I posted here: How do avoid Adrian's C10 replacement short 12V to data line 31?Adrian's Digital Basement has a recent SE/30 repair series, and he shorted data line 31 to 12V accidentally when replacing capacity C10. The link below goes right to the point in video where he found problem: Sounds like the leaking electrolyte removed some solder mask over data line 31...
68kmla.org
I noticed this SE/30 recapping guide specifically calls out "Caution: do not destroy traces near C8 thru C10" - C10 is the one that bit Adrian in video linked above. | |
| Posted by: Spacerog on 2025-05-05 11:16:39 Yup, I'm pulling caps and looking under them now. | |
| Posted by: Spacerog on 2025-05-10 11:27:48 I haven't given up. I've pulled off almost all the caps I put on and I'm double checking traces. Definitely have a short between 12v and 5v but not seeing anything obvious. Trying to locate and follow all the 12v line on the board now. Has anyone mapped out all the 12v traces yet? Is it possible the short is inside the board? | |
| Posted by: Spacerog on 2025-05-12 07:03:45 I found the short. Basically removed every cap, bodge wire, or anything I had touched. Tested after each removal until I found it. Completely my mistake. Now to rebuild everything again and hope I didn't fry the board. | |
| Posted by: cheesestraws on 2025-05-12 07:17:27 Well done. Shorts are a serious pain to find. | |
| Posted by: Unknown_K on 2025-05-12 13:18:55 The only way to real find a short is to use a bench power supply where you can dial in the current max and then use a thermal imaging camera to find the hot spot. You can have a short in the middle of the circuit board between layers and have to Dremel it out. | |
| Posted by: Spacerog on 2025-05-13 07:14:46 Welp, as suspected I'm pretty sure I have fried the 68030 on this board at a minimum. I got and assembled one of those SE/30 Peekers and All the data lines are showing as dead. Thankfully this board has a socketed CPU but I have looked and can't find a replacement anywhere (Can I replace the 16MHz CPU with a 30 or 50MHz?). Also since I still don't get a raster or sound likely fried the Video ROM and possibly other chips. Guess this project goes on the shelf until I can find a donor board.  | |
| Posted by: djc6 on 2025-05-13 07:17:37 I am still new at repairing retro computers, but if 12V was shorted to 5V like you say, it seems possible every chip on 5V rail is fried not just CPU. In Adrian's digital basement video below, he accidentally shorted 12V to data line 31 and every chip on data line 31 was fried: How do avoid Adrian's C10 replacement short 12V to data line 31?Adrian's Digital Basement has a recent SE/30 repair series, and he shorted data line 31 to 12V accidentally when replacing capacity C10. The link below goes right to the point in video where he found problem: Sounds like the leaking electrolyte removed some solder mask over data line 31...
68kmla.org
Can you tell us more about the short? where was it located? How did you detect it/fix it? | |
Posted by: cheesestraws on 2025-05-13 07:26:07I am still new at repairing retro computers, but if 12V was shorted to 5V like you say, it seems possible every chip on 5V rail is fried not just CPU. This is a good point; if youi've shoved 12V up everything that wanted 5V, you may have an ... interesting time trying to get it to work again. | |
Posted by: Spacerog on 2025-05-13 07:32:48I am still new at repairing retro computers, but if 12V was shorted to 5V like you say, it seems possible every chip on 5V rail is fried not just CPU.Yup, I watched that video. Basically I just removed everything i had touched, every cap, every bodge wire, tested after each one, until the short was gone and then reassembled. | |
Posted by: djc6 on 2025-05-13 07:45:40Yup, I watched that video. Do you know what was the one item/location that fixed the short? | |
| Posted by: Spacerog on 2025-05-13 08:48:19 I think it was a bodge I had installed at R13 to the wrong location. | |
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