VOGONS


First post, by Murugan

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Found this one lately. It was in a lot that I bought.
Macs are not my thing though.

When I turn it on, everything seems OK: I got something on the screen,startup sound, HD that I added starts to spin.
I never had this but read about it a lot here and on YT: the fishy smell aka leaking caps.
So I removed the logic board. No leaky caps that I see (probably will have them replaced if I decide to keep it), but when inspecting the PSU I saw these burn marks around C8 and the diode next to it.
Finding a new PSU seems hard and apparently these are known to cause problems. Should I recap or have it recapped and change the diode next to it?

I am kinda tempted to restore the first old Mac that I have 😀

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Reply 1 of 9, by Daniël Oosterhuis

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As an equal parts old PC, old Mac and Commodore geek, my vote goes fully to recapping or having it done professionally. A 68k Mac is always nice, but this is one of the faster ones due to its '040, in this case an FPU-less LC model. If you can find an RC '040 for a good price, it's worth upgrading, at least I think. Do watch out for fakes, Chinese sellers might give you a rebranded LC instead of a real RC '040.

Ethernet cards are also not too difficult to find, as it can take LC PDS cards, but most of them are on eBay in the US, so to get them to Europe, you have to pay like $20 over the $20 or so you're already spending on the card, which is a bit unfortunate. But still, that's WAY cheaper than Ethernet cards for Macs like the SE/30.

I think this is a decent model to get into 68k Macs with, once restored. Only pain-point is the SCSI, because flash solutions for it are more expensive than for IDE and such, as the SCSI2SD often is around €60, which is often the cheapest solution.

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Reply 2 of 9, by derSammler

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Daniël Oosterhuis wrote on 2020-06-08, 13:54:

If you can find an RC '040 for a good price, it's worth upgrading, at least I think. Do watch out for fakes, Chinese sellers might give you a rebranded LC instead of a real RC '040.

RC has nothing to do with that. They are all RC, as that stands for a ceramic package. A 040 with FPU and MMU has simply no letters between "68" and "040". Valid model numbers would be e.g.:

XC68040RC25 (older masks, FPU and MMU, 25 MHz; stay away from any LC/EC variant of this!)
MC68040RC25 (newer masks, FPU and MMU, 25 MHz)
MC68LC040RC25 (newer masks, no FPU but MMU, 25 MHz)
MC68EC040RC25 (newer masks, no FPU, no MMU, 25 MHz)

Personally, I wouldn't care much about the FPU. You won't notice it's missing and the LC can even run without a heatsink, unlike a full 040.

Last edited by derSammler on 2020-06-08, 15:10. Edited 1 time in total.

Reply 4 of 9, by Daniël Oosterhuis

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derSammler wrote on 2020-06-08, 14:02:
RC has nothing to do with that. They are all RC, as that stands for a ceramic package. A 040 with FPU and MMU has simply no lett […]
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Daniël Oosterhuis wrote on 2020-06-08, 13:54:

If you can find an RC '040 for a good price, it's worth upgrading, at least I think. Do watch out for fakes, Chinese sellers might give you a rebranded LC instead of a real RC '040.

RC has nothing to do with that. They are all RC, as that stands for a ceramic package. A 040 with FPU and MMU has simply no letters between "68" and "040". Valid model numbers would be e.g.:

XC68040RC25 (older masks, FPU and MMU, 25 MHz; stay away from any LC/EC variant of this!)
MC68040RC25 (newer masks, FPU and MMU, 25 MHz)
MC68LC040RC25 (newer masks, no FPU but MMU, 25 MHz)
MC68EC040RC25 (newer masks, no FPU, no MMU, 25 MHz)

Personally, I wouldn't care much about the FPU. You won't notice it's missing and the LC can even run without a heatsink, unlike a full 040.

Whoops, yeah, RC isn't a designation for that, my bad. Must be misremembering or read wrong info somewhere. Yeah, an FPU isn't a must at all, if the Mac's being used for average stuff like gaming and desktop apps. I just like having it, much like how I got a Cyrix 387 for my 386DX-40 WIP build. Necessary? No. Gotta have it for the bragging rights? Absolutely 😁

Murugan wrote on 2020-06-08, 14:32:

Think I'll have a look at recapping. Not keen on handling a psu though 🤣.

They're not too bad, if you know what you're doing. Just make sure the caps are discharged, if you have a multimeter, set it to voltage reading and use that to check if the caps hold any charge. You can build a simple cap discharger with some test leads and a resistor (can't remember the recommended value right now, but Google will surely have many results for this project), or do it by just carefully shorting them out, although I do not recommend doing that. You could do damage with that method, although some people claim it always works fine, or that at worst the damage is limited to the bad cap that already has to be replaced. YMMV, at your own risk, etc.

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Reply 5 of 9, by Murugan

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I'll look into it some more before I do it or have it done for me 😀
Does the diode need to be changed next to the burn mark?

Last edited by Murugan on 2020-06-08, 16:07. Edited 1 time in total.

My retro collection: too much...

Reply 6 of 9, by Daniël Oosterhuis

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It's probably fine, and could be cleaned up with some IPA, but if it makes you feel better to have a fresh, clean one in there, you could replace it. I figure it shouldn't be more than an euro or so. I'd probably do it if I were ordering caps for it anyways, FWIW.

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Reply 7 of 9, by Murugan

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Daniël Oosterhuis wrote on 2020-06-08, 16:04:

It's probably fine, and could be cleaned up with some IPA, but if it makes you feel better to have a fresh, clean one in there, you could replace it. I figure it shouldn't be more than an euro or so. I'd probably do it if I were ordering caps for it anyways, FWIW.

Alright alright,I'll keep it 😀
Thanks for the info!

My retro collection: too much...

Reply 8 of 9, by jakethompson1

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You mentioned you got "something" on the screen; if it's just a blank white screen, be aware that a dead PRAM (CMOS) battery on some of those old machines can cause you to get no video. You can get around it sometimes by flipping the power switch quickly off and then on again after the first attempt to turn it on.

Reply 9 of 9, by Murugan

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At first I got the floppy drive icon with the? symbol. There was a HD in it but ummmm well never saw this before.
Anyway, I already removed the battery (no leakage) and I manage to write a floppy with disk tools from IOS 8
This boots so no problems there yet.
First thing is to tackle the smelly things and then find a keyboard and mouse.

My retro collection: too much...