Need help with my Macintosh Plus

[keelus]

Hello there! A few days ago I got a Mac Plus for like 40€, but it's not working (I knew that when buying it).
I've been looking in this and other forums, videos, manuals, and I can't really find the issue. This is what my Mac Plus is doing:

Normally, i press turn on button, and theres no chime nor screen signal. The speaker makes some repeating noises. Also I can hear a bit of electricity maybe? :

I read, that heating the capacitors could help with that problems, and so I did. Doing so, removed the speaker repeating sound, but the rest remaint same:

I decided to wait a bit and, when the heat got cold, suddendly there was chime sound, the speaker sound dissapeared, but the screen remaint black:

I waited like 20 mins and again, back to the beginning issue.




Also here are some photos of the analog and logic board. I would really appreciate your help!

Images in high res: ( https://imgur.com/a/SZrlR7t )
I can take more photos/videos if needed. Thanks in advance

 

[keelus]

UPDATE:
I re-soldered the the flyback transformer and a few pins that looked a bit strange/cracked. Turned it on again and same problem. But, when i heat the board, I got those lines:

Waited for a bit of time, turned it on again and it gave me a sad face! With the code 024000 and then 028000. Which I have no idea what means:

 

[eric]

You can find a resource here for decoding sad mac error codes - maybe ram or something else https://tinkerdifferent.com/resources/sad-mac-error-codes.82/

I'd measure the voltage at the floppy port for 5 and 12 volts and see how low/high they are. low voltage could cause these types of issues. Looking over the analog board for burnt or discolored components is a good next step. May be looking at a recap as well.

 

[keelus]

You can find a resource here for decoding sad mac error codes - maybe ram or something else https://tinkerdifferent.com/resources/sad-mac-error-codes.82/

I'd measure the voltage at the floppy port for 5 and 12 volts and see how low/high they are. low voltage could cause these types of issues. Looking over the analog board for burnt or discolored components is a good next step. May be looking at a recap as well.

The thing is that, later, when the Mac got cold, I got the error code/sad face after a few secs of strange lines as you can see in this video:

Then, I turned it off and unpluged. Came back after 20 mins and got this:

Also, the floppy reader is not plugged, that is a problem/should I plug it in?
To do the recap, where can I buy them online? Thanks

 

[Patrick]

as for caps. i like to buy the kits from console5. but you can also just look at the caps and get them from digikey or other place.

Did you check the voltages ?

not having a floppy drive plugged in should not cause a problem.

the error codes you got seem to indicate the RAM at G11 or G12 (or both?) is bad. I don't know if that would cause the other behavior you are seeing or not.

 

[keelus]

as for caps. i like to buy the kits from console5. but you can also just look at the caps and get them from digikey or other place.

Did you check the voltages ?

not having a floppy drive plugged in should not cause a problem.

the error codes you got seem to indicate the RAM at G11 or G12 (or both?) is bad. I don't know if that would cause the other behavior you are seeing or not.

Thanks! I will be checking voltages day after tomorrow. I will post here when I check them!

 

[keelus]

You can find a resource here for decoding sad mac error codes - maybe ram or something else https://tinkerdifferent.com/resources/sad-mac-error-codes.82/

I'd measure the voltage at the floppy port for 5 and 12 volts and see how low/high they are. low voltage could cause these types of issues. Looking over the analog board for burnt or discolored components is a good next step. May be looking at a recap as well.

Hello! I've just measured the voltage on the floppy port, and all i get is an oscilating voltage between 0 to ~3. It never reaches 0 and its not constant, but it seems that follows a pattern? Also, the 12V one does the same thing but between 3 and 5. You can see better in the video, where I tested 5V:

What could that mean? Thanks in advance.

 

[Patrick]

Looking over the analog board for burnt or discolored components is a good next step. May be looking at a recap as well.

i think that bit from Eric applies.
..

maybe somebody else can be more specific on the forum. but it sounds like the analog board is not happy.

 

[AndyDiags]

Double check for cold solder joints, especially around all the connector and the capacitors near the top on the analog board. You can also try to wiggle/warp the analog board a bit to see if it has any affects during boot; if it does then cold solder points would be the culprit.

 

[keelus]

i think that bit from Eric applies.
..

maybe somebody else can be more specific on the forum. but it sounds like the analog board is not happy.

That's the next thing I'm gonna try, because, I woke up, tried to turn it on again and back to the begginning flop flop flop sound along with black screen.. (tried heating it again, waiting 5 mins, and then turn it on that gives me a sad face again).
I would want to recap, but I live in Spain and buying kits from US it's quite expensive, so that's the last thing I'm gonna try doing if I find myself lost in here.
My question is, can I check every capacitor? So I can check which ones fail?
How is done? Can i check them while they're in the board or, do I have to desolder every single one and test them unsoldered?
Anyways, how it's done? All I have it's a multimeter.

Thanks in advance.
(I'm new in this field so, I'm sorry if I ask simple/easy things )

 

[eric]

Usually multimeters do not have a way to check capacitors. And yes you do need to remove them from the board to test (so at that point you may as well replace them with new ones)

You can get a list of caps and buy them from a more local shop, not sure if mouser or digikey have anything in the EU - @OneGeekArmy may have some pointers.

Console5's tech wiki has a list (not sure what voltage is used in spain) - but here's the 110 and 220 versions:

Mac Analog Board: 630-0108 - TechWiki

wiki.console5.com

Mac Analog Board: 630-0102 - TechWiki

wiki.console5.com

Also @JDW has a video on the whole process

 

[keelus]

Usually multimeters do not have a way to check capacitors. And yes you do need to remove them from the board to test (so at that point you may as well replace them with new ones)

You can get a list of caps and buy them from a more local shop, not sure if mouser or digikey have anything in the EU - @OneGeekArmy may have some pointers.

Console5's tech wiki has a list (not sure what voltage is used in spain) - but here's the 110 and 220 versions:

Mac Analog Board: 630-0108 - TechWiki

wiki.console5.com

Mac Analog Board: 630-0102 - TechWiki

wiki.console5.com

Also @JDW has a video on the whole process

Thanks! Mine's the 630-0108 one. That link was very useful. I wrote down every single capacitor, will go as soon as I can to a local shop and see if they have some of those, and start recapping! That video was really useful as well, will post once I get it done. Thank you very much

 

[keelus]

Hello! Yesterday I replaced the U3 optocoupler for a 4N35 chip, which seemed to fix the flup flup + no chime no video issue. Also, I've just recapped every capacitor on the analog board (except C1 and 2 RIFAs). However, there's no change before and after recapping.
I've just turned it on, got the chime (in a strange way, very loud/low quality?) and after a few secs, a different tone "flup flup flup" sound came back but very quickly, sounded like an automatic gun, stopped and instantly got the chime and I got video with the RAM code 020100 (also, I swaped the RAM positions from, example, ABCD to DCBA and the code now is 028000 which I still don't know how to fix). However, a few lines appeared in the screen.
I know the RAM is failing somehow (because of the code), could that be the issue of the lines? Or other logic (not analog) board problem?
Thanks!

 

[Patrick]

yes. the RAM is also video ram. So if you can replace the bad ram that will prolly be cleared up on screen.

The low chime and flop flop flop might be something else. i'm not sure.....

 

[keelus]

Hi! Just wanted to update that my mac is now working (althought the floppy reader and the display (it's a bit compressed on the bottom, and displaced to the top) both need to be fixed).

Just in case anyone has the same problems as me, what I did so far was:

1. Replace the U3 optocoupler for a new 4N35.
2. Recap most part of the analog board.
3. Get brand new working RAM (4x 256k).

Thanks for everyones help!

 

[pfuentes69]

Hi! Just wanted to update that my mac is now working (althought the floppy reader and the display (it's a bit compressed on the bottom, and displaced to the top) both need to be fixed).

View attachment 10657​

Just in case anyone has the same problems as me, what I did so far was:

1. Replace the U3 optocoupler for a new 4N35.
2. Recap most part of the analog board.
3. Get brand new working RAM (4x 256k).

Thanks for everyones help!

Nice seeing another Mac alive!

Did you check the Dear Mac Scrolls about the screen problem? (Pages 32, 33, and maybe 55)

 

[keelus]

Nice seeing another Mac alive!

Did you check the Dear Mac Scrolls about the screen problem? (Pages 32, 33, and maybe 55)

Yes! The strange thing is that it's stretched on the top part while being a bit compressed in the bottom. Tried the height adjustment but that doesn't seem to fix it.
I played around with a few solder joints and that didn't happened before touching them so, I guess i should resold and clean the flux better , will do asap and see if that fixs that.