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On 7/17/2020 at 4:10 PM, rplacd said:

Not necessarily – the power connectors on the physical AB are different. But the power connectors that plug into other boards are compatible between the Classic and Classic II – after all, you can upgrade a Classic to a Classic II by swapping the logic board.

Not really, if you are just trying to swap AB boards, that won’t work due to different connectors. 

 

But if you remove the yoke from the CRT as well, or the complete screen assembly, all will be fine. 

 

Pretty sure a small adapter from A to B connectors can be hacked easily for testing purposes. 

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Analog board recapped, always triple check, had one marked down wrong (luckily noticed before we started)

 

Still the same issue of needing to be "warm" to boot & for the waves to go away.

 

Anyone have suggestions on what component might need to be "warmed" up to be replaced?

 

Thanks!

 

large.IMG_20200725_142026.jpg.3034f92c5af91d8c021da11ed0a1f15c.jpg

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Soap, water, magic eraser and it's now "clean" - removing the stickers you can see the original color. The front actuallyd came out quite nicely and not yellowed much. Took a few minor spots of rust off and cleaned the inside too.

 

If anyone has ideas on my "needs warming up" recapped PSU I'm all ears.

 

Will be trying some retro bright on the back cover next week as it's so discolored.

 

large.IMG_20200727_164427.jpg.d95e9fdb3963188d4244550c61327ef6.jpg

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18 hours ago, erichelgeson said:

If anyone has ideas on my "needs warming up" recapped PSU I'm all ears.

You might have more luck troubleshooting with a freeze spray type thing; wait for it to warm up and start something running, then cool down bits of the board (reasonably carefully!) and see when it falls over. 

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13 hours ago, cheesestraws said:

freeze spray

Good call, have seen this done before but I haven't tried it.

 

Found a thread on a similar problem from 2019 though it never wraps up - just goes off topic on WD-40 :D http://www.vcfed.org/forum/showthread.php?68426-Mac-Classic-Analog-Board-Low-Voltage-Problems

Has a few things to try though.

 

Edit: Reading through chapter 9 here - a ton of things to try http://www.maccaps.com/MacCaps/Repair_books_files/Mac Classic %26 SE Repair and Upgrade Secrets.pdf

Edited by erichelgeson

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10 hours ago, LaPorta said:

What retrobrite method will you be using?

12% hair product (thought it was 40%, but the label was misleading!) and oxi - the "classic" method I suppose. Still a bit of reading to do. I've done the sun only with good success, but this one is quite yellowed.

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I've solved the Analog board issue!

 

After reading both links above I looked at my board again. There was a lot more electrolytes on the bottom side than I thought - it's not the normal "shiny grime" - more of a slight discoloration - and there was so much of it i honestly thought it was just the normal color of the PCB! I scrubbed a lot with 99% IPA between each contact that i thought could be a bridge and used a tooth pick to clean crust off. Focusing on LL1/LL2 and the other major components. I did note there is quite a bit of yellowing of traces that probably got too hot at one point.

 

I also gave PP1 a twist and clean. Turned it on adjusted till I had stable 5v & 12v.

 

Boots straight up, no checker, no loops, no waves! Huzza!

 

Don't underestimate how dirty these board can get with 25 leaky caps.

 

Tested with load and it's stable @ 11.98v, 4.98v, -11.98

Edited by erichelgeson

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8 hours ago, LaPorta said:

oxy with how much water

Not quite sure yet heading out on vacation tomorrow so will be doing some reading thinking on it. Will let you know what I choose.

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Someone told me that he used 2-3 spoon oxi for about 10 litres of water, but he used hot, nearly boiling water! Did not try it up to now, but I will do that in 3 weeks.

Edited by dochilli

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