Graco ST MAX II 495 PC PRO , paint spray machine help

[zen]

Hi all

Customer mentioned that he overloaded this unit by powering with all settings at full .

Anyone worked on this model before ?

It's a US made device .

A schematic would be really helpful , but not holding my breath .

[SMDFlea]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Hi all

Customer mentioned that he overloaded this unit by powering with all settings at full .

Anyone worked on this model before ?

It's a US made device .

A schematic would be really helpful , but not holding my breath .

I found a repair manual but no pcb schematic. Is there a part number on the pcb

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Thanks

16X297 seems to be the PCB number .

Quite funny when i type it into Google . A repair kit popped up , which is the whole board , at a cost of £370

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

So far found C14,C15,C16 & C17 ( 47MF , 25V ) , poor ESR readings .

Also D16 , which seems to be O/C , has previously been reworked and/or replaced .

Messaged customer to find out what the hell is going on .

[redwire]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

C20 looking preggo, D16 pin not soldered, was a gorilla inside trying to fix this?

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Yes unfortunately

Customer took it upon himself to replace D16 , so now i need to try & discovered part number of original.

C20 on my to do list as well .

[SMDFlea]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Thanks

16X297 seems to be the PCB number .

Quite funny when i type it into Google . A repair kit popped up , which is the whole board , at a cost of £370

There`s some new boards on alibaba https://www.alibaba.com/product-deta...620074426.html ,it doesn`t mention how much the shipping would cost though.

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Thanks , still battling with this one .

U7 ( VIPER 12A ) control chip also seems to be faulty .


D16 is fed from a transformer ,then follows through R17 which is cooked , then to the supply pin 4 ( VDD ) of U7 .


Only 2 pins of D16 are actually connected , therefore assume it's some sort of fast switching rectifier diode .


Can anyone help with replacement advice for D16 ,& also value of R17 , which i assume will be quite low .

[R_J]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

The component installed at D16 now seems to be a transistor (BCR162) any sot23-3 200ma or higher diode should work. Many circuits use a 1N4148 for this diode, so find a similar SOT23-3 (BAT54, BAT54C)
The resistor could be anything low 0~10Ω maybe

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Thanks RJ , yes that was the customer messing about with it .

Was thinking around 10R myself .

[redwire]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

D16 is usually a SOT-23 diode like BAV99, BAS16, MMBD4148 etc. I think BAT54 at 30V is too low. Around 10R looks reasonable for the resistor. C20 must be in bad shape.

What fused? A shorted Viper 12 usually blows the top off, and this board has pretty thin pcb traces and looks 4-layer. Many scuffs and nicks on traces/solder mask. Even parts are trashed, R7, U11- could you use a bigger hammer.
I'd check with an ohmmeter the path from primary cap to transformer to see if there is an open-circuit. I don't see what fused yet.
There's no feedback opto either, so it might not be an isolated supply.
Viper 12 datasheet

[R_J]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

The component installed at D16 now seems to be a transistor (BCR162) any sot23-3 200ma or higher diode should work. Many circuits use a 1N4148 for this diode, so find a similar SOT23-3 (BAT54, BAT54C)
The resistor could be anything low 0~10Ω maybe

The bat54 voltage is a bit low, go for something around 100v

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Hi Redwire ,the scuffs are due to all the hardened glue i needed to removed so that i could gain access to many of the components .

Cheers on the advice for diode type guys , will check to see what i have in stock .

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

All that messing about , then customer pulls repair

[redwire]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

I understand the conformal coating can make the repair extra hell. I use needle probes to poke through for readings, and hot air gun to heat/soften the coating and scrape it off.
TBH the board is a piece of junk, nobody puts a MCU ceramic oscillator right next to the SMPS primary. Skinny traces and more glue please.

Customer seems to keep trying people to repair it for $0.99 or something. If someone already was in there, I don't take on the repair because it can be such a mess.

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Thanks for the additional info Redwire .

I normally pop board onto my pre heater to loosen the glue , but this was quite hard heat resistant stuff & couldn't poke the meter probes through .

Next one i see ,cost will double

[stj]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

some conformal coating disolves with white spirit.

[zen]

Re: Graco ST MAX II 495 PC PRO , paint spray machine help

Great tip STj , will try that next time .