Badcaps.net Forum
Go Back   Badcaps Forums > Troubleshooting Hardware & Devices and Electronics Theory > Troubleshooting Power Supplies and Power Supply Design
Register FAQ Calendar Search Today's Posts Mark Forums Read

 
Thread Tools Display Modes
Old 03-14-2019, 07:14 PM   #1
BigTroll
Badcaps Veteran
 
BigTroll's Avatar
 
Join Date: Sep 2010
City & State: Jefferson
My Country: LAMBDA SOND
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 501
Default Apple ][+ Astec power supply

bought a used apple ][ plus for a reasonably amount, I had it on a total of 3-4 min, while i was on i started to hear a soft sizzle noise and turned it off immediately, good news was it was still displaying digdug on the TV while I was turning it off.

I haven't taken it apart yet but i suspect bad RIFA caps and I was wondering how to select replacments. I would imagine its the same as other mobo caps where you can go higher but not lower. anyways I'll take some pics after I get it apart, I had it powered on at my place of work and it really stunk up the place
__________________
My Computer: AMD Ryzen 7 2700X, Asrock X370 Killer SLI/AC, 16GB Geil EVO X DDR4 3000, 500GB WD Black NVME and 2TB Toshiba HD,EVGA GTX 1080 SC, In-Win 303 White, EVGA SuperNova 750 G3, Windows 10 Pro
BigTroll is offline   Reply With Quote
Old 03-14-2019, 08:51 PM   #2
redwire
Badcaps Veteran
 
Join Date: Dec 2010
City & State: Alberta
My Country: Canada
Posts: 1,167
Default Re: Apple ][+ Astec power supply

Apple II power supply Astec AA11040 or AA11040-B schematic etc. https://ia801002.us.archive.org/1/it...lies_Aug82.pdf
Have to look inside to see what part is failing.
redwire is offline   Reply With Quote
Old 03-14-2019, 10:10 PM   #3
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 20,221
Default Re: Apple ][+ Astec power supply

panasonic sell suitable PolyPropylene caps that are cheap.
stj is offline   Reply With Quote
Old 03-15-2019, 09:33 AM   #4
BigTroll
Badcaps Veteran
 
BigTroll's Avatar
 
Join Date: Sep 2010
City & State: Jefferson
My Country: LAMBDA SOND
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 501
Default Re: Apple ][+ Astec power supply

allrighty got it open indeed the rifa blew but doesn't look like it made to big a mess its a 0.1uf cap 250v i think. I found this site https://www.reactivemicro.com/produc...-power-supply/

thought that would be a good replacement. any thoughts?
Attached Images
File Type: jpg image1.jpg (279.8 KB, 27 views)
File Type: jpg image2.jpg (246.4 KB, 25 views)
File Type: jpg image3.jpg (255.9 KB, 19 views)
BigTroll is offline   Reply With Quote
Old 03-15-2019, 10:21 AM   #5
BigTroll
Badcaps Veteran
 
BigTroll's Avatar
 
Join Date: Sep 2010
City & State: Jefferson
My Country: LAMBDA SOND
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 501
Default Re: Apple ][+ Astec power supply

Quote:
Originally Posted by stj View Post
panasonic sell suitable PolyPropylene caps that are cheap.
I found these would they be suitable? https://www.ebay.com/itm/5pcs-1uF-0-...d/122034179568
BigTroll is offline   Reply With Quote
Old 03-15-2019, 01:29 PM   #6
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 20,221
Default Re: Apple ][+ Astec power supply

that's good, but way overpriced.

you should be paying around 25c each!!
https://uk.rs-online.com/web/p/polye...itors/8697466/
stj is offline   Reply With Quote
Old 03-15-2019, 05:26 PM   #7
PeteS in CA
Badcaps Veteran
 
PeteS in CA's Avatar
 
Join Date: Aug 2005
City & State: San Jose, CA
My Country: USA, Unsure of Planet
Line Voltage: 120VAC, 60Hz & 115VAC, 400Hz
I'm a: Professional Tech
Posts: 2,798
Default Re: Apple ][+ Astec power supply

OMG, hilarious! I'd guess the vintage is ca. 1982, and I'm chuckling at the switch transistor with the part number removed. Astec used NEC TV horizontal flyback transistors.

That's a discontinuous flyback design. If you actually load it to full output power (43W?) those axial rectifiers and the transformer core will get REALLY hot. Guess how I know all this.

So those output caps are excellent quality parts, for the era, but they are ~35 years old. Once you fix the immediate problem, I'd suggest checking the ripple at 50%-75% load. If it's OK, leave well enough alone. If it's not, you have to use the least excellent low impedance caps (e.g. Nichicon RS series) and hope those aren't "too good".
__________________
PeteS in CA

Power Supplies should be boring: No loud noises, no bright flashes, and no bad smells.

Where might is right
There is no right.
- Sophocles in "Antigone"
****************************
All that is gold does not glitter,
Not all those who wander are lost;
- J.R.R. Tolkien, The Fellowship of the Ring
****************************
To kill personal responsibility, initiative or success, punish it by taxing it. To encourage irresponsibility, improvidence, dependence and failure, reward it by subsidizing it.
PeteS in CA is offline   Reply With Quote
Old 03-15-2019, 06:10 PM   #8
RJARRRPCGP
Badcaps Veteran
 
Join Date: Jul 2004
City & State: North Springfield, Vermont
My Country: USA
Line Voltage: 123-127V 61.5-63.5 Hz
I'm a: Knowledge Seeker
Posts: 4,554
Default Re: Apple ][+ Astec power supply

Quote:
Originally Posted by PeteS in CA View Post
OMG, hilarious! I'd guess the vintage is ca. 1982, and I'm chuckling at the switch transistor with the part number removed.
Where? All I saw, except for the caps, what looks like diodes on the PCB, what look like heatsinked diodes or resistors and what looks like a round magnet with a thin heatsink around it. Was it that wide round one on the PCB?

The round one with the thin heatsink, is a package format that makes me get lost, even when I starting learning about more stuff related to PSUs... It reminds me of my early badcaps.net days, when I didn't even know what a MOSFET was, LOL

I saw a round device like that before in a later-1980s' Simplex 4001 FACP. Is that a choke?
__________________
Asus P6T Deluxe

Core i7 Extreme "Bloomfield" 965

PNY GeForce GTX 960

Windows 7 SP1

SoundBlaster ZXR

Corsair TX850M PSU


"There's nothing more unattractive than a chick smoking a cigarette" -Topcat

"Don't eat yellow snow!" -Salem

"did I see a chair fly? I think I did! Time for popcorn!" -ratdude747

Last edited by RJARRRPCGP; 03-15-2019 at 06:32 PM..
RJARRRPCGP is online now   Reply With Quote
Old 03-15-2019, 07:22 PM   #9
BigTroll
Badcaps Veteran
 
BigTroll's Avatar
 
Join Date: Sep 2010
City & State: Jefferson
My Country: LAMBDA SOND
Line Voltage: 120VAC 60Hz
I'm a: Hardcore Geek
Posts: 501
Default Re: Apple ][+ Astec power supply

Quote:
Originally Posted by stj View Post
that's good, but way overpriced.

you should be paying around 25c each!!
https://uk.rs-online.com/web/p/polye...itors/8697466/
I agree but using mouser or any of the other ones shipping is outragous so 6.75 for 5 with free shipping isn't too bad. I did order them!

Power supply has a 1980 copyright inside but the computer is a 1982 based on the logic board stamp of 5082 so week 50 of 82 i guess.
BigTroll is offline   Reply With Quote
Old 03-16-2019, 01:43 AM   #10
stj
Great Sage 齊天大聖
 
stj's Avatar
 
Join Date: Dec 2009
City & State: Europe
My Country: some shithole run by Israeli agents
I'm a: Professional Tech
Posts: 20,221
Default Re: Apple ][+ Astec power supply

the "magnet" is a power transistor.
and as peteS said, it's usually a bu208 < very reliable btw.
stj is offline   Reply With Quote
Old 03-16-2019, 07:24 PM   #11
momaka
Badcaps Veteran
 
momaka's Avatar
 
Join Date: May 2008
City & State: VA (NoVA)
My Country: U.S.A.
Line Voltage: 120 VAC, 60 Hz
I'm a: Hobbyist Tech
Posts: 8,786
Default Re: Apple ][+ Astec power supply

Quote:
Originally Posted by stj View Post
the "magnet" is a power transistor.
and as peteS said, it's usually a bu208 < very reliable btw.
It's an Astec PSU. They generally use very reliable parts... save for those RIFA film caps.
But once you get those taken care of (and maybe the output caps too, as PeteS mentioned)... the PSU should be as good as new. Astec PSUs are near damn indestructible.

Quote:
Originally Posted by PeteS in CA View Post
That's a discontinuous flyback design. If you actually load it to full output power (43W?) those axial rectifiers and the transformer core will get REALLY hot. Guess how I know all this.
Probably worked on a similar (if not same) PSU design many years ago in a former job?
momaka is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



Badcaps.net Technical Forums 2003 - 2019
Powered by vBulletin ®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
All times are GMT -6. The time now is 03:46 PM.
Did you find this forum helpful?