Power Stage Part Numbers Topic is solved

Navy · Post by **Navy** » 05 Dec 2021, 11:19

Hi everyone,

My RHD 1994 850 20v with ECC power stage has failed. I have been trying to locate one for nearly a year now but it's become impossible to match the part numbers. My power stage has 9144355 W409 99A04461, I have seen several second hand power stages for sale but all have different part numbers 9166694 / 9144354. From what I can see they look similar but the electrical connectors are reversed (assume for LHD) but otherwise identical.
Anyone know if all power stages for ECC funtion the same and if it's just the LHD and RHD fitment thats the issue?
Currently in London it's freezing and my wife is fed up using a hot water bottle in the car.

Thanks for any advice in advance.
Andre

Post by **RickHaleParker** » 05 Dec 2021, 11:48

9134933 4DRS Chassis 223919-, 5DRS Chassis 124635-

9144355 4DRS Chassis -223918, 5DRS Chassis -124634 : ( Supersedes 9144354 )
9144354 4DRS Chassis -223918, 5DRS Chassis -124634

FCP Euro has new 9144354 for $133.99 plus shipping. Would be the last one you buy with FCP's warranty. The net cost on any replacement would be the cost of shipping both ways.

9166694 is for the 70 series.

Can you get one open? The circuit should be rebuildable and it should be a simple circuit.

Navy · Post by **Navy** » 05 Dec 2021, 12:32

Many thanks for replying,

The 9144354 appears to be for LHD compared to mine the electrical connections are reversed.
I am hoping (keep cost down) if 9166694 or 9134932 could potentially work as their connections are also reversed that would be ideal.
I guess, I am asking which part number I could take a chance on that may work with some adjustment (lhd/rhd).
I have opened up my power stage several times now and tested the mosfet out of situ and It appears to be functioning correctly. I have changed a diode which was corroded and checked as much as I can with a microscope. Other than a fault with a IC I have no idea what's wrong with mine and I've decided to draw a line under it.
I can still change the mosfet if need be.
Thanks again
Andre

Post by **RickHaleParker** » 05 Dec 2021, 13:19

How about a high resolution picture of the PC board. So we can see the component part numbers are. Figuring out how to source the parts, rebuild them or clone the PC board might be the cost effective way to go.

Navy · Post by **Navy** » 06 Dec 2021, 12:04

Thank you so much for replying.
I reluctantly passed the power stage on to a man who said he may be able to repair it and hopefully tomorrow I shall have it back and working. Tbh I am not sure mobile phone repair and high voltage resistors are the same....similar perhaps!
I am concerned that any repair will be safe as there is always 12v into the power stage (KEY OUT).
I will see the outcome tomorrow and if no luck then pictures will follow.
I would rather buy a used working power stage and adjust it to fit my car.
Many thanks for replying
Andre

Post by **RickHaleParker** » 06 Dec 2021, 15:30

Navy wrote: ↑06 Dec 2021, 12:04 I am not sure mobile phone repair and high voltage resistors are the same....similar perhaps!

In a electronic course you spend a whole semester on one equation, Ohms law. Because if you are well versed in the basics you can fix anything electronic. If he is well versed he can fix it and perhaps make it more reliable.

Navy · Post by **Navy** » 07 Dec 2021, 10:52

Many thanks for all your help.
Ok. we had a storm pass over England this afternoon and it absolutely chucked it down. 10mins of driving and every window was nicely fogged over. So I hopped onto the Tube and collected my repaired power stage (Ahem!) £15 quid lighter I hot footed it back to the car and plugged it in.......
Yipee!! it stil doesn't work.
I have opened it up and taken a picture as per your request but I really think I need another pc board. Also, notice how he repaired the diode I bought...dear..dear........dear.
I would really like your thoughts on this
Regards
Andre

Post by **RickHaleParker** » 07 Dec 2021, 13:15

In a pinch you can hook the blower motor up directly to a 12V on a switch. It will blow full blast when the switch is on but you will have heat and it will hold you over until you figure this out. You can slow it down by adding resistance in series with the motor. A Rheostat or a Potentiometer that can handle the current would give you variable speed.

Are you sure its not the blower motor? A flaky blower motor might be what keeps knocking out the controller. Easy to test just apply 12V directly to the motor. Debris restricting the fan would produce a higher current. That would over heat the the output transistor. Voltage spikes from worn brushes could punch holes in the output transistor.

I do not see any ICs on the board. Looks a pure analog circuit changing resistance on the power supply line to the motor to slow it down the motor.

Have you checked the inputs to make sure you are getting the right signals. Looks like Yellow-Brown, Violet-White and Gray-Red are the speed control lines. Different patterns - different speeds.

Post by **scot850** » 07 Dec 2021, 20:01

Of the 3 part numbers you have listed further up the thread, this one is still listed new at GCP.se in Sweden.

https://www.gcp.se/en/?s=9144354

This is around 100 pounds + shipping.

Volvo were for ever changing and updating part numbers over the years.

Neil.

Navy · Post by **Navy** » 08 Dec 2021, 10:07

Many thanks again for all the replies.
Scot850, many thanks for finding a new blower resistor. That's a great price too however, I read somewhere from a chap in Australia part number 9144354 is lhd and he too was worried about fitment as like myself his resistor is 9144355 rhd in Aussie.
If your link was a identical part number then It would already be on it's way to me. I think since I can't get a rhd resistor I will go for a lhd (probably one from a V70) and try to make a fit. It will be a cheaper loss if it goes belly up.
Thanks again for taking the time to post the link...

Rick,
I removed the blower a few years back and greased the bearing and cleared the dead leaves out. This time I double checked the blower on a bench and she was spinning up nicely. I greased the bearings again and cleaned her up.
Sorry for being a novice but I tried bridging the blue 12v and black ground and the motor ran great but the socket started to heat up and the pins began to glow at which point out came the bridge. I know you must never burn your bridges but that scared me especially as the blue and black wires became warm too. Not sure if I did something wrong or maybe I should use the ground on the car body???
I have attached a picture which hopefully you can see the two IC's. I think there is something called a Zenner diode down in there too.

Regards
Andre