512k sweep/power supply help

[Patnukem]

I have a 630-0102-E that has some parts left off of it, and wanted to find a schismatic for it so I can find some parts for it. Thank you in advance.

 

[tomlee59]

This might help: http://68kmla.org/files/classicmac2.pdf

If not, feel free to e-shred it.

 

[Patnukem]

Thank you I was having trouble finding much of anything.

 

[JDW]

While nothing as detailed and sophisticated as Tom Lee's excellent technical guide, I have confirmed the following analog board information:

http://spreadsheets.google.com/pub?key=pOzKVtKz19Ab2BDc-g73ndA

 

[TheNixer]

Dang, that's an awesome PDF on classic Macs Tom. I've never seen it before but I'm glad to have it now. Thanks!

 

[tomlee59]

Dang, that's an awesome PDF on classic Macs Tom. I've never seen it before but I'm glad to have it now. Thanks!

Thank you for the kind words. If you find any errors or have suggestions for improvement, let me know. One of these days, I hope to update it with the excellent information contributed by the folks on this forum (with proper attribution, of course).

 

[JDW]

I only noticed today that my Google docs spreadsheet (link posted above) had the first note missing. I've added that back.

I also found a Revision-J 630-0102 analog board on EBAY, which the seller claims to have come from a Mac Plus.

 

[Patnukem]

hey I know its been a while for this post but thank you for the information I am finally on my way to fixing it.

 

[Patnukem]

Quick stupid question I am in need of C6 and its a 22uf 50v and I have 2 10uf and a 2.2uf that are 50 or higher volts will the extra 0.2uf going to be too much extra tolerance for the 512k if I install them in parellel? I can always use 2 1uf ones but I would like to put as few in there as possible and I do not want to order one capacitor online and get charged a bunch for shipping. Radioshack has them but only in 35v (they are so lame) I do not think it will be but I just wanted to check.

 

[JDW]

10% tolerance is typical, so for C6, anything between 19.8uF and 24.2uF is perfectly safe to use.

While in theory you may likely be able to get away with a 35v spec part from Radio Shack, it's always best to err on the side of "higher voltage" when it comes to caps, especially caps used in power supplies or old Mac analog boards.

 

[Patnukem]

cool Thank youl I like to use what I have and not have to make a special order, I am going to be using nails for j1 until I get a real one. And I think I found a way to repair the battery holder, I used vinegar to neutralize the acid on it and I am going to solder in some metal plates that should work well.

 

[Patnukem]

I think it was doing this before, when I turned it on I saw the disk ? as expected but then the picture faded off. I could hear some small cracks or sparks at the start of the power abruptly ended shortly after, does this just sound like bad caps? I seep to recall it not fading off before but I do seem to remember a cracking or sparking.

 

[tomlee59]

Take a look at the pdf doc I linked to earlier. It describes the "no raster" problem, its common causes, and the simple cures. The short version: Resolder the four-pin yoke connector on the analog board, check C1 (I'd just replace it, even if it looked good), and freshen up all the solder joint on the flyback transformer. These simple steps clear up the vast majority of the disappearing/flaky/distorted display problem in the classic macs.

 

[Patnukem]

ok sorry i did not see it before . I need sleep soon too much excitement getting my lisa fixed and on for the first time in about 2 years since I found it. Thanks for pointing out what I should search for.

 

[Patnukem]

So strange, I left it unplugged for over a day to dissipate opened it up today and discharged the crt. then I took the paper cover off from the analog board. I see and hear a spark from around the transistor that is located by c40 and r41 on the back of the board and shortly after another. It seems like something that would happen with bad caps.

 

[tomlee59]

So strange, I left it unplugged for over a day to dissipate opened it up today and discharged the crt. then I took the paper cover off from the analog board. I see and hear a spark from around the transistor that is located by c40 and r41 on the back of the board and shortly after another. It seems like something that would happen with bad caps.

Or from bad solder joints.

 

[Patnukem]

you know I read about the solder joins and did not even think about it, but that would make a lot of sense since it seems to only spark when moved around to much. I will redo the solder on the board and see if it is better or worse.

 

[Patnukem]

I re soldered what I could, and it did the same thing as last time I turned in on after being unplugged for a but. When plugged in then turned on it makes a crackle then I can see the screen come on then slowly fade off and turning it off and on will not bring the screen back also when turning it off I hear a squeak, (my old crate amp use to do this too).

 

[Patnukem]

it does not seem like Q11 is working when I test it. The one I removed is C2810 the sheet says 2SC2810 and Q11: 7A, 4-500V, 50W, 18MHz. I do not have either one here is there another equivalent that might work so I can for sure tell if that is the problem. I wish I had the transistor equivalences book right about now The Fairchild pdf says KSC2335 is the closest match but I do not have one either.