Page 2 of 4
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 15:27
by rubber_jonnie
PhilC wrote: 21 Nov 2023 15:12
@rubber_jonnie thanks for that. I’m fine with 415VAC and the like just never worked on a CRT before.
I think I’ll order the rifas and leave this to sit for a while before I do anything with it, then follow the discharge guide.
Sounds good.
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 18:36
by stephen_usher
The RIFAs are far enough away from the high voltage to be safe to desolder. If in doubt stick an anti-static bag to the rear of the high voltage part of the board, it will bleed any high voltage away acting as a bleed resistor and barrier between you and the contacts.
From experience, the Mac Plus screen has a bleed resistor and quickly looses its charge. If you don't disconnect the high tension lead and grounding from the analogue board then you're pretty safe. And you can resolder and replace the RIFAs without removing the board from the computer as they're all pretty accessible, and it's easy to get a moo gun on the leads.
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 18:57
by PhilC
stephen_usher wrote: 21 Nov 2023 18:36
The RIFAs are far enough away from the high voltage to be safe to desolder. If in doubt stick an anti-static bag to the rear of the high voltage part of the board, it will bleed any high voltage away acting as a bleed resistor and barrier between you and the contacts.
From experience, the Mac Plus screen has a bleed resistor and quickly looses its charge. If you don't disconnect the high tension lead and grounding from the analogue board then you're pretty safe. And you can resolder and replace the RIFAs without removing the board from the computer as they're all pretty accessible, and it's easy to get a moo gun on the leads.
Thanks for the advice Stephen. I've got the large Rita and have ordered the small ones. I just want to do a visual of the other boards and sort out anything else whilst its apart and then off we go with building the keyboard and mouse adaptors.
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 19:02
by stephen_usher
The PSU will run without the RIFAs fitted as they're just to filter the power input so as to lessen the high frequency noise going back into the mains.
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 19:54
by exxos
stephen_usher wrote: 21 Nov 2023 19:02
The PSU will run without the RIFAs fitted as they're just to filter the power input
It also filtered the power to the rest of the house by the sounds of it :lol: :hide:
Re: A Macintosh Plus arrived this morning
Posted: 21 Nov 2023 22:33
by Tomswork
I highly recommend reflowing the solder on the flyback and all the connectors on the pcb side
Tom
Re: A Macintosh Plus arrived this morning
Posted: 22 Nov 2023 17:17
by PhilC
Tomswork wrote: 21 Nov 2023 22:33
I highly recommend reflowing the solder on the flyback and all the connectors on the pcb side
Tom
Thanks Tom, I’ll add that to the list.
Re: A Macintosh Plus arrived this morning
Posted: 24 Nov 2023 13:40
by PhilC
The Mac is back on the desk and so far has had the three Rifas removed, the larger one replaced but I’m waiting on the other two to arrive. The large one looked ok but the two small ones look ready to go pop at any moment
IMG_2967.jpeg
So whilst I wait for the two replacements to arrive I’ll check out the motherboard.
IMG_2966.jpeg
It boots, so shouldn’t be too much to worry about (famous last words).
Re: A Macintosh Plus arrived this morning
Posted: 24 Nov 2023 14:15
by rubber_jonnie
Looking very positive :)
Re: A Macintosh Plus arrived this morning
Posted: 24 Nov 2023 14:21
by PhilC
Removed the motherboard, which involved disconnecting the power plug and floppy And then sliding it out the back of the computer and the only issue I could find with it was it being a tiny bit dusty. Why can’t it be this easy to remove motherboards on other computers?
IMG_2968.jpeg
Bit of a brush down and then back in it’ll go. The Rifas haven’t turned up today but I do have a couple of larger ones that I might put in it. We will see.
I was interested to find out that there’s no internal SCSI port on this, so will have to adapt something up externally.