AeroCool VP-550 : IC identification issue

[CapLeaker]

Re: AeroCool VP-550 : IC identification issue

What is the power rate of that 5 bands resistor (1 stage, near the big capacitor) ?

I couldn't find a color code calculator that found the answer using 5 bands.
Looks like it's a 4 bands resistor with a fifth one...

The power rate in Watts of a resistor is based on the size (length and diameter).
And yes there are 5 band colour code resistor calculators. Usually large Chinese resistors have weird values and are harder to get. In a nut shell the 3 and 4 colour band resistors are not telling the power rating in watts. It just tells you the resistance, multiplier and tolerance in that order. The 5th band is temperature coefficient. It’s still morning… hope it makes sense. Lol

[bendeg]

Re: AeroCool VP-550 : IC identification issue

I think I finally found a good info here, at the end of the page, it tells about some exceptions to the rule :

https://eepower.com/resistor-guide/r...or-color-code/

5 band resistor with a 4th band of gold or silver

Five band resistors with a fourth band of gold or silver form an ]exception and are used on specialized and older resistors. The first two bands represent the significant digits, the 3rd is the multiplication factor, the 4th is the tolerance, and the 5th is the temperature coefficient (ppm/˚C).

So, in my case :

Bands 1 and 2 : BROWN - BLACK => 10
Band 3 : SILVER (multiplication factor) => 10 * 0.01 = 0.1 Ohms
Band 4 : GOLD (tolerance) => 5%
Band 5 : GREEN (temperature coefficient) => 20 ppm/°C

Now, that said, it doesn't tell about resistor wattage...

There's another 5 bands resistor in the vicinity of the first one, same look but a bit smaller : RED - RED - SILVER - GOLD - GREEN
=> 0.22 ohms and that's indeed what my DMM gives me.

Maybe it would be a good idea to tell about that exception in the FAQ about resistors.

[momaka]

Re: AeroCool VP-550 : IC identification issue

I think I finally found a good info here, at the end of the page, it tells about some exceptions to the rule :

https://eepower.com/resistor-guide/r...or-color-code/



So, in my case :

Bands 1 and 2 : BROWN - BLACK => 10
Band 3 : SILVER (multiplication factor) => 10 * 0.01 = 0.1 Ohms
Band 4 : GOLD (tolerance) => 5%
Band 5 : GREEN (temperature coefficient) => 20 ppm/°C

Now, that said, it doesn't tell about resistor wattage...

There's another 5 bands resistor in the vicinity of the first one, same look but a bit smaller : RED - RED - SILVER - GOLD - GREEN
=> 0.22 ohms and that's indeed what my DMM gives me.

Yup, I will confirm what you have is a 4-band resistor with the 5th band being used for temp coefficient.
So looks like you found the right info.

In terms of the power rating, though, that looks like either a 2-Watt or 3-Watt resistor to me. 5 Watt resistors tend to be HUGE, so I don't think this one is it.

Probably safe to go with a 3-Watt... or better yet, don't replace it if it reads OK / low-resistance.

Also note, these are flame-proof metal film resistors. Don't use carbon composite unless you want to see a small inferno in there (if/when something fails anyways.)

Maybe it would be a good idea to tell about that exception in the FAQ about resistors.

Probably.
Quite possible the info there hasn't been update in years.

[bendeg]

Re: AeroCool VP-550 : IC identification issue

Ok, you confirm, thanks !

Yup, I will confirm what you have is a 4-band resistor with the 5th band being used for temp coefficient.
So looks like you found the right info.

In terms of the power rating, though, that looks like either a 2-Watt or 3-Watt resistor to me. 5 Watt resistors tend to be HUGE, so I don't think this one is it.

Probably safe to go with a 3-Watt... or better yet, don't replace it if it reads OK / low-resistance.

Also note, these are flame-proof metal film resistors. Don't use carbon composite unless you want to see a small inferno in there (if/when something fails anyways.)


Probably.
Quite possible the info there hasn't been update in years.

Thank you for that information !

I've sent a message to the guy who created the "The Resistor FAQ" thread. I can't do better.

[bendeg]

Re: AeroCool VP-550 : IC identification issue

So far, so good :

New components soldered :

• fuse (6.3A)
• thermistor (SCK-2R56, 2.5 ohms, 6A)
• bridge rectifier (GBU810 instead of GBU606)
• mosfet (MDP13N50)
• diode (original DP8S60P was ok but replaced with a MUR1560)
• capacitor (180uF, 450V, Nichicon). No additionary capacitor as advised by momaka...
• PWM STR6069H

1st test with 80W light bulb in series looks ok, fuse doesn't blow ! (fan not connected yet)

• Small flash then off
• Stand by voltage (purple wire) : 5.22V
• Green wire : 2.65V

Next step : light bulb + power on (green on black) ?

[bendeg]

Re: AeroCool VP-550 : IC identification issue

2nd test, fan connected, with light bulb + power supply tester :
power on (all voltages seemed to be good on power supply tester), fan on, then all went off...

3rd test, no light bulb, power supply tester : all voltages ok (see attachment)

4th test , no light bulb, with 1 HDD : ok, all seems working so far !

As this is my very first "serious" electronic repair, I'm very happy !

Thanks so much guys for all your help !

[CapLeaker]

Re: AeroCool VP-550 : IC identification issue

Congrats! Well done on your first serious electronics repair and you did good!

[bendeg]

Re: AeroCool VP-550 : IC identification issue

Final test to be certain :

A PC powered with ATX and CPU connectors only (I didn't remove the PC power supply to put the repaired one) => ok, no magic smoke or magic smell, fan is spinning gently.

It is working fine under normal load (CPU, system fan, graphic card and its fan, etc...)