My MAC Plus won't start.

[Garryg]

I've got an old Mac Plus that seems to be compleatly dead.
It used to work OK, but I havend had it switched on for years.
When I switched it on recently, absolutely nothing happened!

There seems to be absolutley no power grtting into it atoll.
This is one of the old Macs that take a double A battery that fits into a slot in the rear of the machine, I've replaced it, on the off chance that it would make a difference, it didn't.
I also know the power lead works as I used the same one that I use for a VGA monitor.

I suspect something has went on the power board, is there anything that can easily be checked, and replaced. Or should I just chuck it?

[MacMini2009]

Call Steve Jobs?

[Garryg]

Hmmm, any other suggestions?
I don't think he would return my support-desk calls ;)

[Mac SK]

A new battery is a good start...Lets see, Unplug the power connections on the board and replug them back in. Reseat the ram. Unplug the ribbon off the Hard Drive and try to start up. Does the power supply have the dual voltage switch on the back..slide it one way and then back to 115. Sometimes just repluging stuff in and out will get it going after a long sleep. Good Luck.

[SuperJudge]

It might live yet!

For starters, that PRAM battery is not a AA. It's an Eveready 523, also known as 4.5V PX 21, ANSI 1306AP, or IEC 3LR50. If it's dead, that shouldn't make a big difference (because I have a functional Mac Plus on my desk at work that has a mostly dead PRAM battery), but if a AA battery is in it, my guess is that it won't work correctly. So try getting your hands on the right kind of battery. A bit of Google-Fu should find you a source.

Beyond that, there's nothing particularly easy that comes to mind for troubleshooting.

If all else fails, you can always make a Macquarium (http://lowendmac.com/compact/macquarium.shtml) out of it. ;)

[Garryg]

I think it still has the same battery that was in it the last time it worked.
But surely it should power up whether there is a battery in the (AA sized) slot or not?
I'm almost posative that I've run this without and batery in the slot before... (but that may have beed the Amstrad PC1512!)


Absolutely nothing is happening! No power whatsoever, would a dud, wrong or missing battery do that?.

Does anyone know if there is a site for (preferably fixing) old MACs.

I used to be a computer technician, so I know my way around a soldering iron, so if I knew what I was looking for I could probably fix a dodgy power board, if that's what it is, and I think it must be (unles it is the battery) :(

Oh, by the way this machine dosn't have a hard drive in it, only a floppy, I've got a separate SCSI hard drive, and that still powers up.


Thanks for all the help though.

[MacTech68]

Since you know your way around a soldering iron, I'll take a punt at something.

There are two basic versions of the Power/Sweep board. A 120V only version and a 120V/240V version. There are 4 large capacitors on the 120/240V version near the bottom edge.

On the 120/240V version, along the bottom edge is a 33K ohm resistor that often goes open-circuit. It makes the machine totally dead.

Obviously, there are many other possible causes, such as the fuse but that resistor was the most common problem for a completely dead board.

The original resistor is a 33K ohm 1/2Watt carbon.

The 120V Only board will have a similar resistor but of a different value. It's usually connected across the large 100uF 200V electrolytics to discharge them. It's marked as R41 and is 100K (probably 1/2Watt).

See this pdf (http://home.earthlink.net/~gamba2/images/plus_analog.PDF) for a circuit at the bottom of page 6 of the 120V ONLY version.

Good Luck! :)
________
Subaru B9sc (http://www.toyota-wiki.com/wiki/Subaru_B9sc)

[Mac SK]

Some guy over on another forum has some Mac Plus's to get rid of.
http://www.mac-forums.com/forums/other-hardware-peripherals/161075-very-very-old-mac-plus.htmlp

[Garryg]

Since you know your way around a soldering iron, I'll take a punt at something...Thanks, I will buy the resistor next time I'm near Maplins and punt away!

By the way, the fuse is ok, I checked that, and nothing looks obviously fried.

'Eat it'... yes... ok... I'll do that then... :confused::D

Thanks for the link as well, but I'm more interested in fixing it than getting another one, ex-technicians never die... well not untill they stick the soldering iron into the wrong thing :eek: