Recapping Analog Boards of 128K/Plus and SE series

[nvdeynde]

Hi,

I'm wondering how many of you have already started with recapping 128K-Plus Analog Boards or the SE series.

Even though the capacitors still look fine and test good on ESR as well, they 128K Analog boards are now 28 years old.

In the Mac SE Power Supply from Sony there's a large 620uf, 350 volts radial capacitor (non screw type, contact points are 2 thick pins ).

I have been looking everywhere and the only replacement capacitor I could find were with mounting screws.

I guess that part even doesn't exist anymore...

A cosmetic issue is that replacement capacitors are available, with a rare exception like the 620uf 350v, but in most cases they are a lot smaller than the original one's.

Especially on the 128K-Plus Analog Boards the difference will be obvious.

I would like to keep everything as original as possible, even the looks of a recapped board.

The only solution I can see is to choose higher voltages, these are bigger so you get more or less the same dimensions as the original one but with higher voltage.

Take Care,

Nico

 

[LOOM]

Yeah, I'm actually planning to do the same on my Plus this summer.

I've seen some people mentioning the higher quality 'tantalum caps' in other threads. Is that the one we should use on the Plus analog boards as well?

So in addition to nvdeynde's questions, my specific question is;

Does anyone know how many caps, and which types that need/could be changed on a Plus analog board?

 

[techknight]

Or, just do what they do in the tube world. Restuff them.

 

[Byrd]

If you purchase caps from a place like Element 14/Farnell/RS components, you should be able to match up the original cap sizes more accurately. I find though the order takes a lot longer though when you order in more obscure parts, which is understandable.

Most of the large caps however are now dwarfed by more modern replacements, but the hole sizes seem to match up OK.

JB

 

[techknight]

cap sizes have shrunk considerably over the years. But what I am saying if someone wanted to go for that original look, then buy tiny small replacements of the same value, take apart the original cap, throw its guts away and stuff the new one inside it.

high value tube audio and radio/TV equipment people restore, do this very same thing.

 

[tt]

technight, that's a cool idea.

I have been thinking about recapping my analog board as well, and perhaps the Sony power supply. I also would like to try to keep it looking sort of stock. I noticed one cap had been replaced with a much higher voltage rating which is about the same size as the original. A list of dimensions and values would help to source the closest parts possible. When I recapped my SE/30 board I was able to get fairly close dimensional equivalents.

I remember there was a long discussion with JDW trying to find a more powerful PSU to stuff into the SE / SE/30 PSU, but I think it got lost in the form data outage, did any viable substitute get discovered? I would like to beef mine up a little due to the upgrades. I am aware of the artmix version, but it's pretty pricey.

 

[nvdeynde]

cap sizes have shrunk considerably over the years. But what I am saying if someone wanted to go for that original look, then buy tiny small replacements of the same value, take apart the original cap, throw its guts away and stuff the new one inside it. .

Isn't it easier than to just go for higher voltages, same capacitance of course to match the original size of the cans ?

Replacing a 16 volts for example with a 35 volts won't do any harm.

Nico

 

[nvdeynde]

List Capacitors Macintosh SE PSU:

-1x 620uf, 400v Radial : D=40mm, H=42mm ( D= Diameter and H= Height, metric values )

- 2x 4.7uf, 350v Radial: D=16mm, H=26mm

- 1x 100uf, 16v Radial: D=5.5mm, H=15mm

- 1x 47uf, 25v Radial: D=5.5mm, H=15mm

- 1x 1uf, 50v Radial: D=5.5mm, H=15mm

- 3x 22uf, 25v Radial: D=5.5mm, H=15mm

- 3x 470uf, 16v Radial: D=10mm, H=13mm

- 3x 2200uf, 16v Radial: D=13mm, H=26mm

- 1x 6800uf, 10v Radial: D=16mm, H=30mm

- 1x 3300uf, 10v Radial: D=13mm, H=25mm

Macintosh SE Analog Board

- 1x 3.9uf, 100v BP Radial: D=13mm, H=30mm

- 1x 1000uf, 16v Radial: D=16mm, H=20mm

- 1x 4700uf 16v Radial: D=18mm, H=36mm

- 2x 220uf 16v Radial: D=10mm, H=20mm

- 3x 100uf, 25v Radial: D=8mm, H=13mm

-1x 10uf, 160v Radial: D=10mm, H=20mm

- 1x RMC470 ceramic

- 3x MKT 0.1K 100V Box: L=12.6mm

- 1x Q_F333J 400V Film Poly: L=17mm, D=6mm

- 1x Axial - Nichon N9008

- 1x Axial - Nichicon N9004

Macintosh Plus Analog Board ( International version 230 volts)

- 4x 2200uf, 16v Radial: D=18mm, H=35mm

- 1x 4700uf, 16v Radial: D=18mm, H=35mm

- 1x1000uf, 16v Radial: D=16mm, H=25mm

- 1x 220uf, 16v Radial: D=10mm, H=20mm

- 2x 470uf, 10v Radial: D=8mm, H=12mm

- 2x 22uf, 50v Axial: L=16mm

- 1x 47uf, 16v Axial: L=14mm

- 1x 33uf, 16v Axial: L=13mm

- 2x 4700pF, 250v Box: L=13mm

- 1x 474K, 400V Metal Poly: L=23mm

- 1x 3.9uf 35v Bi Polar: D=18mm, H=35mm

Macintosh Plus Analog Board - 120 volts USA version

There's a spec sheet here:

https://docs.google.com/spreadsheet/ccc?key=0AnmQLg8d1xThcE96S1Z0S3oxOUFiMkJEYy1nNzNuZEE&hl=en#gid=0

Most of the boards listed also above have ceramic capacitors too that I didn't list because I couldn't read the values of them: most of them did not have a voltage rating. I hope someone else will be able to complete my lists.

Is it necessary to replace the ceramic one's as well ?

Take Care,

Nico

 

[techknight]

Yes, nothing will stop you from going to a higher voltage.

But what I am saying is for original look and appearance. New caps dont fit the appearance of old caps, for example the green guys. They dont make that style shrinkwrap anymore. I mean you could try and scavange the shrinkwrap and stuff it onto the new can.

Or you can "not care" and stick anything you like in there. (like me)

 

[LOOM]

Macintosh Plus Analog Board ( International version 230 volts)

- 4x 2200uf, 16v Radial: D=18mm, H=35mm

- 1x 4700uf, 16v Radial: D=18mm, H=35mm

- 1x1000uf, 16v Radial: D=16mm, H=25mm

- 1x 220uf, 16v Radial: D=10mm, H=20mm

- 2x 470uf, 10v Radial: D=8mm, H=12mm

- 2x 22uf, 50v Axial: L=16mm

- 1x 47uf, 16v Axial: L=14mm

- 1x 33uf, 16v Axial: L=13mm

- 2x 4700pF, 250v Box: L=13mm

- 1x 474K, 400V Metal Poly: L=23mm

- 1x 3.9uf 35v Bi Polar: D=18mm, H=35mm

Where did you find this information? I can't see it in the spec sheet you mentioned.

Are any of these very expensive, or are they all equally expensive/cheap?

 

[nvdeynde]

The list is an inventory I made myself before I started repairing the boards.

However for the 128K/Plus Analog board one has to keep in mind that here in Europe, we use the International 230 volts version: it can be different from the 120 volts model for the USA. I can't tell as I don't have on of these.

As for the price of the capacitors: If you want good one's from Panasonic or Nichicon rated at 105°C and 5000 or 7000 hours, it becomes an expensive matter...

 

[nvdeynde]

As promised, here are the photos of my recapped Mac Plus Analog Board.

Before:

After:

 

[LOOM]

I'm trying to find the '3.9uf 35v Bi Polar: D=18mm, H=35mm' for the Macintosh Plus International version as listed above.

Are there any similar caps I can use instead that's easier to find? Preferably from futurlec: http://www.futurlec.com/cgi-bin/search/searchold.cgi?Q=3.9uf&E=1&X=0

And this one: 474K, 400V Metal Poly: L=23mm

Is that a resistor or what? a 400 voltage capable 475 kOhm resistor?

 

[nvdeynde]

I'm trying to find the '3.9uf 35v Bi Polar: D=18mm, H=35mm' for the Macintosh Plus International version as listed above.
And this one: 474K, 400V Metal Poly: L=23mm

Is that a resistor or what? a 400 voltage capable 475 kOhm resistor?

The 3.9uf 35v BP HF doesn't exist anymore as electrolyte capacitor: replace with Panasonic ECW-F2395JA ( Polypropylene BP HF 250 VAC capacitor )

The 474K, 400V metal Poly is a 0.47uf capacitor: replace with Panasonic ECQ-E6474KFB

 

[techknight]

replacing film and ceramic capacitors are pointless. The only thing you need to worry about replacing is the electrolytics.

I have mica/polyfilm/ceramic caps from the 50s/60s that are still good.

 

[LOOM]

But all these used to be electrolytics, right? The panasonics mentioned replace the last two (electrolytics?) because they don't exists..

Macintosh Plus Analog Board ( International version 230 volts)

- 4x 2200uf, 16v Radial: D=18mm, H=35mm
- 1x 4700uf, 16v Radial: D=18mm, H=35mm
- 1x1000uf, 16v Radial: D=16mm, H=25mm
- 1x 220uf, 16v Radial: D=10mm, H=20mm
- 2x 470uf, 10v Radial: D=8mm, H=12mm
- 2x 22uf, 50v Axial: L=16mm
- 1x 47uf, 16v Axial: L=14mm
- 1x 33uf, 16v Axial: L=13mm
- 2x 4700pF, 250v Box: L=13mm
- 1x 474K, 400V Metal Poly: L=23mm
- 1x 3.9uf 35v Bi Polar: D=18mm, H=35mm

Or how do I know what's electrolytics here?

I can't find "Panasonic ECQ-E6474KFB" anywhere either. I've added everything else from the list on futurlec.com, but I'm not sure which one from that site to replace with the last two on the list..

 

[nvdeynde]

replacing film and ceramic capacitors

I do replace them when I the outside shows cracks.

In case for the Mac Plus Analog board: the Kemet AC filter/surpression capacitors of 4700pf and 470nf definately need to be replaced as on all my 8 Analog boards their box was severaly cracked.

I agree not to replace them as long as they are still within specs ( even Ceramic capacitors can go out of specs badly ) and if they pass visual inspection.

 

[techknight]

You cant compare line safty caps vs standard caps, Saftey capacitors are an exception, they are different.

Those arnt standard capacitors by the way, they are special line filter capacitors.

In the tube radio world they used regular capacitors on the line and they loved to explode. Nowadays they make a special type of capacitor that is designed to go directly across the AC line.

Ceramics go bad thermally, they have a poor thermal response but thats the property of ceramic capacitors, and smart engineers usually dont use ceramics in critical portions of circuits. Usually in better designed circuitry, integrators and oscillators, or anything circuit that is critical to its operation use film caps.