Apple II and IIe power supply RIFA replacements

18 posts / 0 new
Last post
Stargeezer's picture
Offline
Last seen: 1 day 18 hours ago
Joined: Aug 4 2020 - 12:06
Posts: 145
Apple II and IIe power supply RIFA replacements

Merry Christmas all:

Perhaps the community can help me out here.

I am in the processe of replacing RIFA caps on a Kaypro power aupply.  Since I am ordering the replacements from Mouser, I though I would maximize my shipping expense and get replacement caps for my Apple II+ and IIe.  Doing the work on the Apple IIs isn't on my hobby schedule at the momen since my bench ins covered in Kaypro guts.  So I am hoping to avoid disassembling the Apple IIs, extracting the PS, and them poping them open just to see what values I will need to purchase.  I know that Apple had some different sourceing for PSs over the years of II production, but did they all use the same value RIFAs? 

My Googling of PS images seemed to show 0.1uf and .22uf caps are present. 

  • Are these pretty much standard? 
  • Are they they X1 or X2?
  • What dimesional size are they (Mouser seems to offer various dimensions lxwlh and pin distance)
  • Does anyone recommend replacing any other caps while I am in the patient?
  • Oh yeah, after thought>> does the IIC+ use RIFAs too?  I could replace those while I'm at it too.

 

Replacing the PS with new modern ones from ReactiveMicro is not of interest to me.

 

Thanks all! :-)

mark

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
Unfortunately there isn't a

Unfortunately there isn't a simple single annswer on what types and values the caps are in Apple II power supplies because they aren't standard.  Aluding to what you mentioned, Apple used at least two manufacturers, Astec and Dynacomp, and each of those made several different power supply boards over the years.  Most of them use the translucent yellow plastic RIFA brand caps that are famous for blowing up and spewing noxious smelling smoke.  However, I've also seen some that use different mains caps that are of a different type of plastic that isn't prone to that.  And of the RIFA brand caps, I've seen different sizes and values.

 

The bad news based on the above is that you really aren't going to be able to get around yanking the power supplies and opening them up to see what is in there.  I bought a bunch of the common sizes and values a while back .

 

As for the Reactive Micro power supply boards, they're great and extremely easy to use and professionally done.  But the method described in other posts by Uncle Bernie and expanded to other power supply variants by other people including myself (AE power supply) using the Mean Well PT-65B and a 7905 regulator to rectify the -5V is significantly less expensive and also provides great results.

 

That said, I understand why you'd like to preserve the originals, and certainly just pre-emptively replacing the RIFA caps is even less expensive.  I do that myself for original power supplied that haven't failed.  I do the power supply board replacements on ones that have failed and just replacing the obbiousl components doesn't get them going again.  It's usually a lot easier than the work needed to diagnose failures if they aren't simple.  Also it is easier if there are multiple electrolytics that look suspicious, show signs of leakage, bulging, etc.

 

Stargeezer's picture
Offline
Last seen: 1 day 18 hours ago
Joined: Aug 4 2020 - 12:06
Posts: 145
Thanks

Thanks for the guidance.

I had a suspicion I was going to need to pull the PSs in order to know what I had in my units, but it was worth asking before up-ending everything.

I will check out your AE power supply posts and Uncle Bernie's too.Thanks again.

Cheers,

mark

 

Offline
Last seen: 2 hours 36 min ago
Joined: Feb 27 2021 - 18:59
Posts: 500
you probably will have to open them if only to check

You don't need X1 rated safety capacitors in a residential or commercial setting, X2 is the sufficient (and required) rating.

X1 is tested to withstand 4 kV pulses without failing (exploding), whereas X2 is tested to withstand 2.5 kV pulses. Basically, it depends on how "dirty" the local electrical system is. The higher voltage pulses are only found around heavy equipment in industrial settings. Is your Apple in use next to a MIG welder?

Not all Apple II power supplies were made by Astec, and the ones that were did not always use 'RIFA' metallized-paper capacitors. For example, see the one from Liza Loop's computer here. The service manual published by Apple, "ASTEC Power Supplies (Aug 82)", lists safety capacitors of both 0.1 µF and 0.22 µF; on the Apple II supply AA11040 it only lists 0.1 µF.

You can replace the metallized-paper type safety capacitor with a polypropylene film type. These don't destroy themselves over time but they perform the same function. Apparently "ECQ-U2A104KL" will fit as a substitute for the RIFA in a AA11040B or C revision. I don't have one to measure myself, but blogs report the lead spacing to be 20 mm.

If you have an ESR meter, you could check on the health of the electrolytic capacitors, but I wouldn't replace them preventatively.

The Apple IIc+ uses a Sony CR-60 power supply that does not contain any RIFA type capacitors.

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
robespierre wrote:You don't
robespierre wrote:

You don't need X1 rated safety capacitors in a residential or commercial setting, X2 is the sufficient (and required) rating.

X1 is tested to withstand 4 kV pulses without failing (exploding), whereas X2 is tested to withstand 2.5 kV pulses. Basically, it depends on how "dirty" the local electrical system is. The higher voltage pulses are only found around heavy equipment in industrial se

 

I don't recall ever seeing a power supply that came originally in a ][+ that wasn't made by Astec, but in //e at some point they switched from Astec to Dynacomp and pretty much all, if not all of the Platinum //e and IIgs came with Dynacomp made power supplies.

 

I'm not sure who made the early ][ supplies, the silver ones.  But the ones usually encountered in ][+ are gold colored and Astec labeled.  The Dynacomp ones in later //e, Platinum //e and IIgs are normally silver colored.  The ones in Platinum //e and IIgs usually have vent holes and a spot to mount a fan.  The IIgs ones have a different motherboard connector.

 

The replacements I bought for the RIFA caps are of the poly type.  Those don't have the hard plastic case that turns brittle with age and cracks and eventually allows air inside which causes them to burn out.  I have seen a few original power supplies that used the poly type also.  They're usually white and smaller in size  than the RIFA caps.

 

I also don't nomally recommend replacing electrolytics unless they show signs of bulging or leaking. 

Offline
Last seen: 11 hours 54 min ago
Joined: Sep 9 2021 - 01:43
Posts: 23
Astec and Dynacomp

Some thoughts on Astec and Dynacomp.

 The original supply in my //e upgraded to a GS was a Dynacomp dated from 85.  It had a bare aluminum can.  This has caused the steel back plate to corrode.  I can not find a RIFA cap on the board.  DC must have used a different brand with a different cover for this part.  There is not a solder mask layer.  The fuse is soldered to the board.

 The ROM 1 standard GS has an Astec supply.  The Astec does have the RIFA cap.  The case on the cap is cracked.   Everything else on the Astec is much better than the DC.  The fuse is user replaceable, there is a solder mask.  The can is galvanized steel, "silver" colored.  The traces on the board are great, most of the copper has been left on the board.  The heat sinks are better.  There is a place to mount a fan.  The transformer is bigger.  It should have better efficiency and line regulation.

 I have replaced both supplies with RM's units.  Someday I may recap the Astec and put it back in.

 

 

Offline
Last seen: 6 days 19 hours ago
Joined: Apr 26 2016 - 08:36
Posts: 685
Modnarmai wrote:Some thoughts
Modnarmai wrote:

Some thoughts on Astec and Dynacomp.

 The original supply in my //e upgraded to a GS was a Dynacomp dated from 85.  It had a bare aluminum can.  This has caused the steel back plate to corrode.  I can not find a RIFA cap on the board.  DC must have used a different brand with a different cover for this part.  

There is no RIFA branded capacitor on my DynaComp power supply, but it does have two X1 rated filter capacitors.  They are the non-explody kind.

RIFA was not the only supplier for these things.

 

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
baldrick wrote:Modnarmai
baldrick wrote:
Modnarmai wrote:

Some thoughts on Astec and Dynacomp.

 The original supply in my //e upgraded to a GS was a Dynacomp dated from 85.  It had a bare aluminum can.  This has caused the steel back plate to corrode.  I can not find a RIFA cap on the board.  DC must have used a different brand with a different cover for this part. &

 

 

Correct that RIFA was not the only brand of filter capacitor out there, they just wre extremely common.  Most Astec made supplies have them.  Some Dynacomp made supplied used the RIFA brand and some used the poly cased kind.  Some 3rd party branded supplies and ones in clones used RIFA caps also. I had a RIFA branded cap let out the smoke in a Franklin power supply for example.  I had just got the machine and was testing it out and was going to replace the RIFAs...  too late.  It wasn't even on 5 minutes when smoke started rolling out the top of the power supply.

 

What makes this confusing to some is that "RIFA" has become like "Kleenex".  It has become a generic term that people use for all filter  caps, even those that aren't made by RIFA and even sometimes for ones that aren't even made the same way.

 

I would pre-emptively replace any RIFA branded cap or anything made similarly to those.  RIFA caps are pretty much not a matter of if they will let out the smoke, it is when.  Pretty much without exception every one I've looked at in recent years has shown the crazing and cracking in the hard translucent plastic cover that is a sign it is about to let go.  I would not bother changing out the other type of filter cap.  I've yet to see one fail like a RIFA.

 

 

 

 

Offline
Last seen: 3 hours 43 min ago
Joined: Jun 6 2020 - 10:50
Posts: 418
This sort of reminded of a

This sort of reminded of a related question that's been rattling around in my head for a while. What are the thoughts on replacing a film cap connected to mains that is properly rated for AC voltage, but does not carry an X or Y rating? Often these are big maroon dipped caps I've seen in early 80s equipment, probably before X and Y ratings. Obviously they aren't going to blow like a rifa. But is there any benefit to replacing them with a proper X or Y rated cap?

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
nick3092 wrote:This sort of
nick3092 wrote:

This sort of reminded of a related question that's been rattling around in my head for a while. What are the thoughts on replacing a film cap connected to mains that is properly rated for AC voltage, but does not carry an X or Y rating? Often these are big maroon dipped caps I've seen in early 80s equipment, probably before X and Y ratings. Obviously they aren't going to blow like a rifa. But i

 

 

I wouldn't bother.  Even the X and Y filter caps aren't really that necessary these days.  Some people just remove RIFA caps and don't replace them at all.  I replace RIFA caps as I said in a previous message, but if the older caps are not of the bad type I wouldn't mess with them unless you had some indication they were failing.

 

But...  IANAEE  ...  I Am Not An Electrical Engineer

 

 

 

 

Offline
Last seen: 6 days 19 hours ago
Joined: Apr 26 2016 - 08:36
Posts: 685
Theoretically any capacitor

Theoretically any capacitor of around 0.1 uF or so will work provided it has a voltage rating high enough.

In older electronics we used to use 1.5kV rated ceramic types 0.1 uF or 0.01 uF and they worked just fine.

The X1 and X2 ratings are primarily safety ratings, so that your power supply doesn't catch fire if the capacitor fails.

To quote an electrical engineer:  

X1 and X2 capacitors are safety-rated to be placed line-to-line or line-to-neutral.

X1 are pulse tested to 4kV; X2 to 2.5kV.

They are “self-healing,” in that an internal arc will vaporize the metal around the internal short and open it back up.

 

As for whether or not to replace or just remove...they were put there to keep noise out of the AC lines in your home.  With all the crap we have plugged in nowadays, mostly powered by janky Chinese switching power supplies it becomes more important than ever to keep those filter caps in there to maintain some semblance of cleanliness of the AC power.

It DOES make a difference, whether you see it or not. Your power supply will probably last longer as will many of your other devices plugged into your mains.

 

Offline
Last seen: 2 hours 36 min ago
Joined: Feb 27 2021 - 18:59
Posts: 500
RFI

A lot of the RFI compliance is done to help radio users. If you have a satellite TV system or listen to shortwave radio you already depend on the noise suppression capacitors in your nearby equipment.

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
As I said, I replace RIFA

As I said, I replace RIFA caps with poly cased replacements that are similarly rated to the originals.  Even if it isn't strictly "needed" I agree that keeping power clean is a good idea.  But every time I mention replacing them someone will commet that you can just leave them out, so I re-emptively mentioned that as a possibility.

 

Offline
Last seen: 3 hours 43 min ago
Joined: Jun 6 2020 - 10:50
Posts: 418
To further elaborate on my

To further elaborate on my question, here is an example of a cap I was questioning from an old mid 80's power supply a while back.  It's clearly rated for 125vac and was connected across the mains in an "X" scenario.  No safety markings, except for Underwriters Labs and a Canadian logo of some kind.  Although given that my mains average 123vac these days, a 125vac rated cap doesn't leave much room.  Typically X/Y caps these days are rated to 275vac.  So maybe these should be replaced just for the marginal voltage rating alone, regardless of the lack of an X/Y rating?

 

 

Offline
Last seen: 1 month 1 day ago
Joined: Jul 5 2018 - 09:44
Posts: 2587
You could but frankly these

You could but frankly these gumdrop type caps I wouldn't bother.  They seem to hold up and rarely ever fail.

 

CVT
CVT's picture
Offline
Last seen: 12 hours 10 min ago
Joined: Aug 9 2022 - 00:48
Posts: 1024
nick3092 wrote:...Although
nick3092 wrote:

...

Although given that my mains average 123vac these days, a 125vac rated cap doesn't leave much room.

...

 

This is just a rating for the North American power grid and it doesn't mean it cannot handle voltages above 125V. Mains interference suppression caps of this sort are overengineered to handled much higher voltages. They usually print the AC voltage that applies to the UL, CSA or VDE marks that they carry. This is why it's not unusual to see both 125VAC and 250VAC on the same capacitor:

 

Stargeezer's picture
Offline
Last seen: 1 day 18 hours ago
Joined: Aug 4 2020 - 12:06
Posts: 145
Finally replacing RIFAs......

I am finally getting around to beginning the great RIFA replacement.

I am starting with the caps in the power supplies of a couple of Kaypro II machines I recently received.

I am looking at different sourcing.  These particular power supplies need .22uf and 4700pf RIFAs.  I started looking in the usual place, Mouser.

It looks like the .22uf with a pin pitch of 20mm can cost as much as $2.50 a piece.   I that high or are these typcal prices or can anyone recommend a better source for parts?

CVT
CVT's picture
Offline
Last seen: 12 hours 10 min ago
Joined: Aug 9 2022 - 00:48
Posts: 1024
Stargeezer wrote:...It looks
Stargeezer wrote:

...

It looks like the .22uf with a pin pitch of 20mm can cost as much as $2.50 a piece.   I that high or are these typcal prices or can anyone recommend a better source for parts?

 

Very often if you want the exact lead spacing of a retro-cap, you will have to pay top dollar, because standards have changed. But there is no need for that. You can simply use 15 mm or 22.5 mm. They will sit a little higher, but there is no requirement that says that they have to touch the board. Here are some from DigiKey: click!

Log in or register to post comments