Testing a Quadra 660AV Power supply..

[tthoms]

So, as I try to restore the Quadra, I thought that I'd start with the power supply.  Searching the forums, I didn't find anything related to the pin configuration for the 9 pin socket that goes to the motherboard.  I took a volt meter to it and this is what I found:

Positive lead (Black) to Negative lead (Blue): Voltage seems to oscillate between 3-4 volts.

Positive lead (Yellow) to Negative lead (Black): Voltage seems to oscillate between 7-8 volts.

Positive lead (Red) to Negative lead (Black): Voltage reads in at 4.2 volts

Any idea what that means?  Assuming that Black is ground, it seems noisy at least.

I looked for a way to open the PSU, but I can't seem to find anything that isn't taking a screwdriver and prying the sheet metal apart.  If there is a useful trick, I'd love to hear it.

Thanks for any advice you can offer.

 

[tthoms]

So, I figured out how to get into the power supply.  At first glance, everything looks good.



No bulging capacitors, the board looks really clean,  until....



There seems to be a lot of grease or goo around the transformer.   Is that normal?  if not, can you replace them?

 

[Unknown_K]

My 660av came dead and I ended up replacing my PS and it worked. I meant to see if I can fix it but have not got around to it (fixing PS is not my favorite thing to do).

Anyway I might dig it out this weekend and take a look. Are there more then one model of supply for the 660av?

 

[Unknown_K]

Well I was down in the lab working on a DELL and the PS was close by so I took a look at it.

Astec AA16990 Apple 614-0022

Capacitor ,Voltage, marked uf, test uf, Ohm, Voltage drop %

c25 , 10, 470, 544, .19. 1.3

c27 , 25, 220, 212.5, .19, 1.2

c11, 25, 47, 49.39, 1.2, .9

c28, 16, 1000, 917.4, .18, 1.3

c29, 16, 1200, 1095, .09, 1.3

c26, 10, 2200, 2216, .06, 1.8

c9, 200, 330, 312.6 , .11, .7

c10, 200, 330, 305.5, .14, .4

c45, 10, 220, 236, .28, 2.0

c46, 25, 47, 48.7, .95, .9

c30, 35, 10, 10.96, 4.9, 4.1

C30 seems a bit funky at first look at the numbers.

 

[tthoms]

My 660av came dead and I ended up replacing my PS and it worked. I meant to see if I can fix it but have not got around to it (fixing PS is not my favorite thing to do).

Anyway I might dig it out this weekend and take a look. Are there more then one model of supply for the 660av?

Not to my knowledge, but I'm new at this.

 

[tthoms]

Well I was down in the lab working on a DELL and the PS was close by so I took a look at it.

Astec AA16990 Apple 614-0022

We seem to have the same model.

Capacitor ,Voltage, marked uf, test uf, Ohm, Voltage drop %

c25 , 10, 470, 544, .19. 1.3

c27 , 25, 220, 212.5, .19, 1.2

c11, 25, 47, 49.39, 1.2, .9

c28, 16, 1000, 917.4, .18, 1.3

c29, 16, 1200, 1095, .09, 1.3

c26, 10, 2200, 2216, .06, 1.8

c9, 200, 330, 312.6 , .11, .7

c10, 200, 330, 305.5, .14, .4

c45, 10, 220, 236, .28, 2.0

c46, 25, 47, 48.7, .95, .9

c30, 35, 10, 10.96, 4.9, 4.1

C30 seems a bit funky at first look at the numbers.

I haven't even looked at the capacitors.  Does your transformer have orange grease/ goo on it?  I'm also curious about the voltages that you get out of the motherboard connector.

 

[Unknown_K]

Looks like glue or epoxy to me.

 

[tthoms]

I found a link discussing this PSU in depth: https://www.badcaps.net/forum/showthread.php?t=62455&highlight=astec+aa16990

It seems you can't measure the voltage output unless the PSU is under load.  I'll see what I can figure out.

 

[tthoms]

Using a 12 auto lamp (the kind for static timing adjustments) the new readings are:

Yellow  11.8 V

Blue 10.9 V

Red 4.3- 4.4  still some oscillation on this circuit.