Are RIFAs needed for Plus?

[68kPlus]

Hi,
Just wondering if it's 100% necessary to have C33 and C36 installed on an international Mac Plus AB.
Also, is it true the late Mac Plus' have bleeder resistors? My Plus is from June 1990.
Thanks

 

[bibilit]

IIRC they are not really required, but they are so cheap i will replace them to keep the board more or less original.

 

[cheesestraws]

You should replace them if you can. They are not there because the Plus needs them, they're there to stop the Plus feeding crap back into the power network and screwing up other devices.

 

[68kPlus]

You should replace them if you can. They are not there because the Plus needs them, they're there to stop the Plus feeding crap back into the power network and screwing up other devices.

That makes sense. I have 4x RIFAs for my Plus, but I still need more soldering skills

 

[bibilit]

I still need more soldering skills

this is pretty basic to be honest

 

[68kPlus]

this is pretty basic to be honest

True, but I'm not good at soldering at all. I've never really done through-hole soldering.

 

[68kPlus]

You should replace them if you can. They are not there because the Plus needs them, they're there to stop the Plus feeding crap back into the power network and screwing up other devices.

Do RIFAs have polarity?

 

[cheesestraws]

Not unless my memory is really playing tricks on me

 

[Iesca]

Through-hole soldering is very easy. Bruce Rayne has some great tutorials on through-hole and surface-mount. You can also watch Dave Murray (The 8-bit Guy) solder new through-hole caps in a Plus and get the basic idea.

They are definitely recommended, as they're part of a protection circuit, as has been mentioned.

As for the Rifas themselves, you can still buy their modern equivalents. They will even be marked as Rifa, though they are manufactured by Kemet. And no, they are non-polar, so no worries on that front. However, you don't necessarily need Rifa-style caps, you can use any similar X2 and Y2-class film caps, as needed.

 

[Iesca]

These are the ones I ordered for my Plus (I only needed 3)

0.1 µF, 275V, X2-class (x1)
Digi-key #399-7483-ND (Manufacturer #PME271M610MR30)


4700 pF, 250V 1000V, Y2-class (x2)
Digi-key #399-5411-ND (Manufacturer #PME271Y447MR30)

 

[joshc]

There is no polarity to RIFAs, insert them either way you like. The most important bit is getting the right type/class and voltage rating.

 

[68kPlus]

Through-hole soldering is very easy. Bruce Rayne has some great tutorials on through-hole and surface-mount. You can also watch Dave Murray (The 8-bit Guy) solder new through-hole caps in a Plus and get the basic idea.

They are definitely recommended, as they're part of a protection circuit, as has been mentioned.

As for the Rifas themselves, you can still buy their modern equivalents. They will even be marked as Rifa, though they are manufactured by Kemet. And no, they are non-polar, so no worries on that front. However, you don't necessarily need Rifa-style caps, you can use any similar X2 and Y2-class film caps, as needed.

I bought these:

https://au.element14.com/kemet/pme271y447mr04/cap-4700pf-20-paper-radial/dp/2332435

They seem to match 100% the original International AB spec.

 

[68kPlus]

There is no polarity to RIFAs, insert them either way you like. The most important bit is getting the right type/class and voltage rating.

I'll probably just solder them in the same way the originals are.

 

[68kPlus]

These are the ones I ordered for my Plus (I only needed 3)

0.1 µF, 275V, X2-class (x1)
Digi-key #399-7483-ND (Manufacturer #PME271M610MR30)


4700 pF, 250V 1000V, Y2-class (x2)
Digi-key #399-5411-ND (Manufacturer #PME271Y447MR30)

My Plus has the later red cap for the 0.1µF RIFA, so it's fine. The two I have are:

• Rated voltage: 250 VAC 50/60 Hz
• Capacitance range: 0.001 - 0.1 µF

I bought them as 4700pf, so they should be fine (let me know if I'm wrong)

 

[Skate323k137]

True, but I'm not good at soldering at all. I've never really done through-hole soldering.

Strongly recommend at least the 1st video in this series; even knowing how to solder, it did wonders for my worksmanship and consistency. It's also excellent at explaining how and why solder works, how flux works, and what makes a good connection.

https://www.youtube.com/playlist?list=PLL2SJnXPlHhK-atII3OJOW5uzFwBVJJJ3

 

[Iesca]

Those vintage Pace videos are great!

 

[Phipli]

I'll just chip in and say...
Desoldering is more tricky than soldering although you'll still be fine. I'd but a couple of cheap ebay soldering kits (some clocks or christmas trees or something) and build them up, then practice removing some of the components and putting then back.

On a £2 board it won't matter if it goes wrong.

 

[68kPlus]

I'll just chip in and say...
Desoldering is more tricky than soldering although you'll still be fine. I'd but a couple of cheap ebay soldering kits (some clocks or christmas trees or something) and build them up, then practice removing some of the components and putting then back.

On a £2 board it won't matter if it goes wrong.

I did something similar to what you said. I practised through-hole soldering on a no-good board, and I just succesfully did the RIFA recap!
Thanks everyone for the help!

 

[Iesca]

Congrats! Definitely a sense of pride when you first learn to do it.

 

[Phipli]

Awesome well done.