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Pekopome
September 12th, 2012, 06:05 AM
Hey guys. I have a 512K that makes no sign of life at all when I power it up. No sound no electric humming. The analog board looks ok. No leaking caps or bad soldering (of what I can see). I still think the analog board is the problem since there is no sound at all. Or could it be the motherboard

I have read that many have had success with washing a motherboard in the dishwasher on a quick program without soap. My question for you guys is. Have you tried it and is there a chance the trick will work with the analog board as well or is that no go?

/ David

patscc
September 12th, 2012, 06:08 AM
You're sure the power supply is working ?
Does the board look gunky ?
patscc

olePigeon
September 12th, 2012, 08:10 AM
I've done it with a normal motherboard. It didn't fix the problem, but it did make it look very nice. I had to recap the motherboard for it to work. No major problems, though.

smeezekitty
September 12th, 2012, 05:21 PM
I tried cleaning the motherboard on an old apple that had a distorted display but it had no effect.

Chuck(G)
September 12th, 2012, 05:25 PM
Some of the Macs will play dead if the PRAM battery's a goner. Replace it and they come back to life. Don't know if your SE is one of those.

Crypticalcode0
September 13th, 2012, 12:43 AM
Hey guys. I have a 512K that makes no sign of life at all when I power it up. No sound no electric humming. The analog board looks ok. No leaking caps or bad soldering (of what I can see). I still think the analog board is the problem since there is no sound at all. Or could it be the motherboard

I have read that many have had success with washing a motherboard in the dishwasher on a quick program without soap. My question for you guys is. Have you tried it and is there a chance the trick will work with the analog board as well or is that no go?

/ David

Yes, this works but this is only part of the solution.
In general this is done with boards to get the gunk out of it.(Industrial boards have this usually)
After this you usually can see the problem by just taking a good look at the board.(Knowing where to look for helps.)

Pekopome
September 13th, 2012, 11:43 PM
Ok. So it got my hands on another analog board leftover from an 512K to Mac Plus upgrade. Don't think it have been in use since 1986....

Installed it in the machine. Turned it on and "Dong" the computer made the Mac sound for the first time and tried to boot of the floppy but no picture. After af few secound this weird crackling sound came from the computer. And after a few seconds more white smoke began to come out of the air wents.

I can't find any visual damgage on the analog board. But it is a bit dirty. Thinking about giving it a go with the dishwasher. What are your thoughts?

Crypticalcode0
September 14th, 2012, 01:24 AM
Ok. So it got my hands on another analog board leftover from an 512K to Mac Plus upgrade. Don't think it have been in use since 1986....

Installed it in the machine. Turned it on and "Dong" the computer made the Mac sound for the first time and tried to boot of the floppy but no picture. After af few secound this weird crackling sound came from the computer. And after a few seconds more white smoke began to come out of the air wents.

I can't find any visual damgage on the analog board. But it is a bit dirty. Thinking about giving it a go with the dishwasher. What are your thoughts?

When you think such things, measure the caps before testing....

If it smelled like cat piss you have blown a elco.
Else GL and happy hunting down that broken component.

patscc
September 14th, 2012, 05:00 AM
Guys, dirty electronics do not automatically imply non-functioning. I mean, when your ECM is acting funny in your car, do you immediately steam clean the engine ?
No, you start checking ODBC codes and testing.
Let's see some testing here, instead of just this Homemakers's thread of "Well, how do I wash this or that thing in the dishwasher"
'Cmon, we're all blood, guts, and solder folks here, right ?
patscc

Pekopome
September 14th, 2012, 06:44 AM
Guys, dirty electronics do not automatically imply non-functioning. I mean, when your ECM is acting funny in your car, do you immediately steam clean the engine ?
No, you start checking ODBC codes and testing.
Let's see some testing here, instead of just this Homemakers's thread of "Well, how do I wash this or that thing in the dishwasher"
'Cmon, we're all blood, guts, and solder folks here, right ?
patscc

Hehe dude - the problem is my repair skills are very limitied. I have no idea what an ODBC is. I see it as a miracle I was able to change the analog board, well maybe I wasn't since smoke came out.

The visual inspection doesn't reveal any thing. But maybe I should power it up without the cover and see where the smoke is coming from...;)

barythrin
September 14th, 2012, 09:50 AM
Do you or a friend have a multimeter? They're cheap and a good intro to electronics. Some folks here can give you some good spots to test with one.

patscc
September 14th, 2012, 11:03 AM
Pekopome said

Hehe dude - the problem is my repair skills are very limitied.
No problem. Just ask, that's what most of us are here for. Don't worry about ODBC, it's a car protocol for reading trouble codes.
Do you have a multimeter or voltmeter ? How about a small soldering iron ?
patscc

Crypticalcode0
September 14th, 2012, 11:03 AM
Hehe dude - the problem is my repair skills are very limitied. I have no idea what an ODBC is. I see it as a miracle I was able to change the analog board, well maybe I wasn't since smoke came out.

The visual inspection doesn't reveal any thing. But maybe I should power it up without the cover and see where the smoke is coming from...;)

:shocked: errr, wasn't that what killed it in the first place?
Visual inspection will not bring you further then you need to measure it through not plug it in again and probably do more damage then you can fix!!!

A few basic rules when fixing stuff.
1. Measure, a known value.
2. When a resistor or a capacitor burns out, check connected components for damage
3. Don't Assume anything is Okay until your measurement verified it.
4. When know it's broke and you unsure don't plug it in, it's a fire hazard.
5. Verify your tools and equipment before and after use.

I have experience in the low and mid voltage range.(12KV is fun till someone gets hurt)
And I fix electronics for a living, I hope this crisis is over soon then i can get back to design and testing again.

Gabriele72
September 15th, 2012, 08:49 AM
To me, earlier Macs (up to the Plus) look much more immune to caps leakages or similar problems. While I would try the dishwasher trick with a SE or later, I would consider other things in a 512K, first. If you already found the problem is in the logic board itself, I would start measuring impedances on the power connector. Just disconnect it from the power supply and verify there's no shorts between the voltage pins and ground. Once I had a completely dead Plus because the keyboard pins were shorted. I was blaming the power supply but it was only doing its job: sensing a short and keeping the machine off.
A shorted tantalum capacitor is an usual culprit.

patscc
September 15th, 2012, 12:46 PM
I have a NeXT MO drive that's not working. Maybe I should try running it through the dishwasher ? ;)
patscc

tezza
September 15th, 2012, 03:25 PM
Yes, I would look for a blown capacitor. These are often obvious due to the blackened/melted nature of the phenomena.

I'm one of those people that have washed boards, and have written about the experience. Sometimes I've washed them because they have been covered for so much organic gunk (like mouse droppings) it wasn't safe or practical to work with them. Other times I've tried it as a solution to a specific problem as in leaky Mac caps. Here the dishwashing got rid of the residue.
http://www.classic-computers.org.nz/blog/2009-04-13-mac-classic-2-dishwasher-fix.htm

This worked, although so did something a lot less radical
http://www.classic-computers.org.nz/blog/2012-01-09-classic-ii-cottonbud-solution.htm

I wouldn't wash a board unless there was specific reason to do so. It's unlikely to help unless the issue is leaky caps, and these can easily be seen in the (pre-washed) board.

These older Macs can be hard to fix and I've had some frustrating experiences
http://www.classic-computers.org.nz/blog/2009-04-23-Mac-SE-resurrection-bridge-too-far.htm

I agree with the others in that the first step is to get some basic tools and do some diagnostic tests. However, if you don't want to do that, the alternative is to look for a replacement board or machine. I doubt if dishwashing will help. Either way, good luck with it.

Tez

Crypticalcode0
September 15th, 2012, 04:00 PM
I've washed Amiga's before to neutralize the battery acid from a leaking battery.
But that require adding something to the wash i wouldn't like to use inside a dishwasher...

bibilit
September 16th, 2012, 06:38 AM
Cleaned quite a few motherboards (logic boards) that way, the first one is a bit scary...then you get used to it (most were not working before the process)

Gabriele72
September 17th, 2012, 02:18 AM
I've washed Amiga's before to neutralize the battery acid from a leaking battery.
But that require adding something to the wash i wouldn't like to use inside a dishwasher...

Did it show the usual greenish residue from corroded traces all around the battery?

I've read that those batteries might be alkaline, hence a mild acid solution should be used. What did you add to the wash and what where the results? Did you just wash and rinse the board or also scrub it e.g. with a toothbrush ? I will soon receive a computer which suffered from battery leakage and I'm very interested in the subject.

Crypticalcode0
September 20th, 2012, 02:40 AM
Did it show the usual greenish residue from corroded traces all around the battery?

I've read that those batteries might be alkaline, hence a mild acid solution should be used. What did you add to the wash and what where the results? Did you just wash and rinse the board or also scrub it e.g. with a toothbrush ? I will soon receive a computer which suffered from battery leakage and I'm very interested in the subject.

I've had some mixed results in the past, I used concentrated lemon juice in the dishwasher.(You still should clean it a little by hand afterward and it really depends on the amount of damage you have to start with!!!)
I have used paint thinner and cleaning Spirit to get rid of nasty stuff by hand some of the silk screen might come off using that stuff though.

RickNel
October 29th, 2012, 02:04 PM
I've read that those batteries might be alkaline, hence a mild acid solution should be used.

White vinegar is a good mild acidic cleaning and neutralizing agent, safer than hydrocarbon solvents. For a local issue like battery or trace corrosion, apply with toothbrush then rinse off with moist cotton rag. Then brush your teeth if you like...;)

richardtj
November 8th, 2012, 05:02 AM
That immediately makes me think of dead Caps- particularly Electrolytic that will "blow and smoke" becuase they're designed for high voltage electricity. That in turn implies video power source as that in itself would be working at some 10k volts.