Thread

Mac Classic 2 Problem Diagnosis.

Mac Classic 2 Problem Diagnosis. Troubleshooting 41 posts Jun 17, 2009 — Jul 8, 2009

#1 Wed, 17 Jun 2009 - 13:39

Hey everyone!

I Bought a Macintosh Classic 2 off of Ebay for 10 $ (Plus 22 Shipping

) . It comes with a keyboard and a Mouse. The Description says that it starts up to a Flat line on the CRT and that the Vertical Sweep circuit is blown out. According to this site: http://www.biwa.ne.jp/~shamada/fullmac/repairEng.html

They Say

"(1) The first thing to do is to check the P1 connector. If the problem is caused by connection/soldering failure of the P1 connector, you will see the burnt and/or charred P1 connector. Desolder, clean and resolder the P1 connector.

(2) If the problem still persists and the culprit is the U2 IC chip, replace it with a new TDA1170N chip.

When the U2 IC chip is broken, you may see another symptoms such as:

(1) The screen is shrunken to the upper/lower half of the monitor and the opposite half blacks out,

(2) The upper/lower half of the screen is extended in the vertical direction."

Does anyone know of this Problem on a Classic 2? The site above was made to repair the Macintosh SE and not any other...

Thanks!

#2 Thu, 18 Jun 2009 - 23:31

Lack of vertical deflection in a compact Mac is almost always caused by a poor connection. Resoldering (with fresh solder) the yoke connector should be performed as a matter of course. After doing so, pull out the cable and inspect the mating surfaces for oxidation, burning, etc. Repair/replace as necessary.

In very rare instances, the vertical deflection IC blows. IIRC, it is still a TDA1170 in the Classic II. This chip is very common, and probably still widely available. But resolder the yoke connector first, and see where things stand at that point.

#3 Fri, 19 Jun 2009 - 15:49

Hey there! Thanks!

I Got it and test started it. It makes a strange fart like sound on start up. and there is a flat line on start up.

I haven't taken it apart yet but I will.

#4 Fri, 19 Jun 2009 - 16:02

Actually the Fart sound stopped...

I get a Bright Horizontal Line but no chime.

#5 Sat, 20 Jun 2009 - 08:54

HI Mars478, I would tackle the vertical scan collapse first. As Tom said re-solder the connector and see it that works. The missing chime is most likely due to leaking capacitor on the logic board, the Classic II's are notorious for that. It's probably best to sort out one thing at a time. Just be careful not to run it too long with the white line showing, it will burn into the phosphorus, leaving you a permeant line.

#6 Sat, 20 Jun 2009 - 14:38

Thanks! I am a new to the Compact Macs so How would I get to the Analog board without dying

Is there a Guide?

Also the Line on the Screen spans edge to edge. It is different from Damians Picture on Flickr.

#7 Sat, 20 Jun 2009 - 16:46

Have you managed to download Tom's notes? http://68kmla.org/files/classicmac2.pdf The notes go into detail about the hazards of working inside a compact and how to discharge a CRT. The line is probably different because the CRT width is set wider.

#8 Sat, 20 Jun 2009 - 18:31

Yeah I downloaded the PDF.

I see no visible Corrosion on the Analog board or on the connector that is showed.

To Remove the analog board I have to discharge the CRT?

Thanks!

#9 Sun, 21 Jun 2009 - 06:07

To Remove the analog board I have to discharge the CRT?

Yeah I would. But you may not have to remove the analogue board to make the repairs.

According to Larry Pina's Mac Classic Repair book, most likely a horizontal white line is a symptom of a broken or cracked solder joint at connector BD1 on pin 1 on the bottom of the connector. The crack may also be on the width coil at LL2 or on the horizontal deflection capacitor at LL1.

In which case, all you need to do is remove the vinyl jacket and re-solder the joints at these locations.

#10 Sun, 21 Jun 2009 - 16:28

Here's a bad update. I posted this to another forum, and I got the reccomendation to whack the top of the case, it did bring the video back for HALF a second but the video went off. Now I get no video...

Any idea how to fix this!

Hahahahahh!

#11 Sun, 21 Jun 2009 - 20:11

I got the reccomendation to whack the top of the case, it did bring the video back for HALF a second but the video went off. Any idea how to fix this!

Yeah, follow the advice you have been given here. Whacking the top of the case is not likely to hurt it, beyond what is already damaged, but it is a common remedy that might temporarily resolve this particular problem. What whacking it does is temporarily make contact with a weak or cracked solder joint, until the high frequencies running across it vibrates it apart again or the Mac gets jostled. Most likely in your case whacking the Mac caused a permanent break in the solder, too far apart to to be mitigated by this rough approach. If you allow it to sit power up for several hours, the expansion from the heat might allow a good whack to make a connection. Other other hand, it could further weaken other joints. The only way to fix this is to go in and re-solder the suspect joints.

This more or less confirms what most of us have been thinking.

#12 Sun, 21 Jun 2009 - 23:28

Yeah I'll keep it running for a while without brightness (so that the phosphor does not get burnt) for a while...

Thanks I'll update this soon.

#13 Mon, 22 Jun 2009 - 15:51

Hi, I left it running for about an hour and I got no video at all.

Should I just resolder all the connections on the Analog board?

Arghhhhhh I WANT THIS TO WORK!!!

#14 Mon, 22 Jun 2009 - 16:11

Hi, I left it running for about an hour and I got no video at all.Should I just resolder all the connections on the Analog board?

Arghhhhhh I WANT THIS TO WORK!!!

Follow the good advice already given here, which is to resolder all joints that look suspect. Another thing to consider is replacing the capacitors on the analog board with new ones. By doing this, you will avoid the potential problem of leaking/bulging capacitors in the future. When working near the analog board, yoke, anode cap/lead and video board, make sure you have discharged the CRT to the ground lug first. This will ensure you are protected against serious injury. Possibly more importantly, take it very slow when working inside the machine -- knocking the end of the neck is easily done if you're not careful, and will result in a dead CRT.

#15 Tue, 23 Jun 2009 - 00:42

I know the CRT is working because there is a little light in the Glass neck.

Also is this an example of Corrosion on my motherboard?

#16 Tue, 23 Jun 2009 - 03:47

resolder all joints that look suspect.

Chances are a cracked solder joint will not be visible to the naked eye. Take note of the locations I mentioned above per Larry Pina's repair instructions and re-solder all leads attached there, whether they appear to need it or not.

And yes your logicboard appears to show a leaky capacitor. It may need to be replaced, but definitely cleaned and probably re-soldered.

#17 Tue, 23 Jun 2009 - 12:31

There are some solder joints on the analog board that seem to be more brownish in color. Is that A bad solder joint?

#18 Wed, 24 Jun 2009 - 14:19

So I am going to reflow all of the suspicious Solder joint which look brownish right?

#19 Wed, 24 Jun 2009 - 19:48

So I am going to reflow all of the suspicious Solder joint which look brownish right?

No you are going to identify the solder joints at the locations I and others specified above. If it is clear that the solder joint was scorched, and not just discolored, then you have a component failure as well. The best way to identify that is to look for scorch marks on the back of the white vinyl panel that covers the analogue board. Otherwise as pointed out earlier, cracks in solder joint are usually not visible without microscopic inspection. If you see any obvious defects, then by all means secure the connections. Otherwise, it is best to proceed location by location. If the places I have relayed from Larry Pina's book to not restore the Classic, I can give you a list of all the trouble spots to investigate. Though from the description of your problem, I gave you only those that applied.

#20 Wed, 24 Jun 2009 - 23:09

In the time you've taken to post repeatedly, you could've soldered every joint on the analog board.

You've been given lots of good advice, why not take it? Solder -- don't just "reflow" -- the specific connections that have already been pointed out to you. The yoke connections are the first things to take care of. If you read the classicmac2.pdf doc, you will find advice that these connections should be resoldered whether or not you can see anything wrong, along with explanations for that advice.

The symptoms you describe are pretty common, and the likely solutions are well documented.

#21 Wed, 24 Jun 2009 - 23:55

OK Thanks! I am just very nervous about screwing this up. I Played with soldering on an old PC Board and it was pretty easy so I am going to give it a go. This is my first (Hopefully) Useful Solder job ever.

Thanks to the support everyone has given, and sorry if I am pushy!

:beige: :b&w:

#22 Thu, 25 Jun 2009 - 00:39

OK I soldered, I soldered the connections on the yoke. All the connections near the speaker.

Most of the CRT Controls as well. With new solder. I did some extra soldering on some suspicious joint, and I accidentally joined to solders together. I tried turning it on for a few seconds, it made a loud squeaking noise, and there was a bright light in the glass neck of the tube. I Quickly turned it off. I need to get a desoldering tool as well, but I do not know if this is progress or not.

Thanks!

#23 Thu, 25 Jun 2009 - 15:48

OK So I de soldered the two joints I accidentally connected, and I resoldered half of the Vertical IC Chip.

It just displays no video, nothing at all. There is a faint orange light in the glass neck, and it makes a pop sound from the speaker at boot.

Would I have to replace the WHOLE analog board? or is it like the CRT or something.

Arghhhhh.

#24 Fri, 26 Jun 2009 - 19:57

Since nobody else has posted, I shall do so. By bridging two components together, and then applying power, you have most likely fried something on the analog board. Since I have limited hands-on experience with the insides of a compact Macintosh myself, do not take my word for it, but that is my initial thought. It might be a more sensible decision to simply acquire another compact instead of working further on your Classic II. Let this be a lesson to you in the future though - be less curious and take more time with repairs. It might be useful to let us know which joints you bridged.

#25 Fri, 26 Jun 2009 - 20:11

Unfortunately wackymacs is right. You have killed something on that analog board, and possibly also damaged the crt (bright flashes emanating from within a crt are a very bad thing). Debugging that new problem (which is almost certainly more complex than the original one) on top of what you were already trying to do is asking a lot. You're better off getting another unit, and performing a transplant.

And if you need to solder anything in the future, please be sure to inspect your work very carefully before reapplying power. Haste is costly.

#26 Wed, 1 Jul 2009 - 00:15

No, I bridged two joints on the same component...

There is not a bright flashing light in the back, its just a faint glow, like a lightbulb but VERY faint...

I'll take a picture. Would Washing the Mobo do anything? The MoBo does have some corrosion.

I really want this mac to work. Do you think a good idea is a replacement Analog board?

Arrrr.

#27 Wed, 1 Jul 2009 - 01:02

No, I bridged two joints on the same component...

That can and generally will still fry things.

There is not a bright flashing light in the back, its just a faint glow, like a lightbulb but VERY faint...

Please get your story straight.

I did some extra soldering on some suspicious joint, and I accidentally joined to solders together. I tried turning it on for a few seconds, it made a loud squeaking noise, and there was a bright light in the glass neck of the tube.

(bright flashes emanating from within a crt are a very bad thing).

#28 Wed, 1 Jul 2009 - 01:11

It was not flashing as described.

Now it is in the current state it was in before, after I hit the top corner of it.

I am sorry if I seem rushed or my facts are not correct.

Would a new analog board do me good?

#29 Wed, 1 Jul 2009 - 07:11

As I already said, it would probably be better to just get another one off eBay, unless someone will send you an analog board for cost of shipping. There's still the chance that another part of the CRT assembly, or the CRT itself, is now damaged.

#30 Wed, 1 Jul 2009 - 12:58

Is there a way to tell if the CRT is damaged?

Anyone want to buy it from me