Plus - Partial Power?

[Scott Baret]

So this is a new one to me.

I picked up a Plus (upgraded 128K from the 11th week of 1984) from the son of the original owner. It's been in storage since 1991 and came to me in the box of the computer that replaced it (an SE SuperDrive).

The machine turns on and the floppy drive makes its sound like it should when the computer is turned on, but there's no chime and no video. Tapping it on the side does nothing (often brings these back) but the lack of the chime is a little confusing here.

Any idea what the culprit could be in case I need to order parts or get some refurbished? My first thought upon seller description was that the analog board solder joints just needed reflowed but I'm wondering if something more is up.

It's like it gets some power (hence the title) but doesn't go all the way on.

 

[Byrd]

First up I'd take off the lid and keep tapping the analogue board around the usual dry solder zones, it might spring to life all of a sudden.

No luck, reflow without fail and then replace RAM

 

[Callan]

Sounds like your not getting 5v. Your going to have to check your solder joints on the power connector before you can asses what you'll need. (besides caps - don't forget the rifa's). Check for any battery damage too. I just got done repairing 2 that the batteries had leaked on - no fun! While you're doing the power connector make sure to check the neck and deflection connectors too. They all can have broken joints. Check the connector on the motherboard for cracked solder joints too.

 

[Scott Baret]

I do have a functional spare analog board...should I try that first just to see if it springs to life?

 

[Callan]

I'd look it over first. It might be as simple as a bad solder joint. Also visually check everything before replacing the analog ( the motherboard and floppy). You never know what the previous person did or tried to do.
I haven't had much luck with those analog boards. Of the five i've worked one, they've all needed something fixed on them besides reflowing the header pins. That might just be my bad luck though. Yours might be better!
I have had good luck with flybacks, though - all good!

 

[Scott Baret]

In this case it may be what wasn't done given that this computer has essentially sat for 35 years. I'm also not sure what kind of conditions it was in (I'd assume a garage since the computer has a lot of black gunk on it that will probably take me 20 minutes and a lot of isopropyl to clean up).