KAD32 Supercharger issue - First sign of insanity

[Somerset Taz]

I've decided to start a new post on this issue. Over the past couple of seasons my Bavaria 29 Sport's port KAD32 has burnt out two supercharger controllers. After the first one I checked the wiring and had the clutch replaced. All was well - for a time - then mid season the controller failed the supercharger was on permanently and the breaker had popped. Whilst out of the water I rechecked and cleaned the wiring, had the alternator tested and fitted an isolator switch in the white cable on the supercharger clutch (both engines). All was ok for a time last season then, towards the end on the season, I noticed that whilst the supercharger was switched on (i.e. isolator switch to on) the supercharger was on permanently again and that the breaker had popped, again.

I think the supercharger controller has been fried (again!) - there's a short between pin 31 and S1. I'm in danger of falling into the "first sign of insanity - making the same mistake and expecting a different outcome"!
So I assume something other than the new clutch or alternator is frying my controller, but now I can't test the whole setup as I don't have a serviceable controller. Any tips on how to check the system, kick down sensor etc without a controller please? I'm not going to just swop bits from one engine to the other and risk the other engine's controller.
Also and possibly connected(?) on the same engine there's an irritating gremlin with the tacho. When running single engine the tacho reads ok but when the other engine is running too the tacho drops to about 1100 and stays there. Could the gurus suggest a possible cause of that issue so that I can fix it and eliminate it from possible link to my supercharger issue. This relatively simple system is driving me nuts! Cheers.

 

[BruceK]

You are not going insane. Its a poor design and the simple and cheap answer so it never happens again is fit a relay between the black box and SC so the black box only ever triggers the relay and the relay protects the black box from over current. There is already one in there for the starter motor, you'd have thought they'd do the same for the SC .... doh

 

[Somerset Taz]

Thanks Bruce, it's a relief that someone thinks I'm not going mad!

(Being lazy) Can you recommend a part number or type for the relay please and is there a simple wiring schematic I can refer to, to ensure I get it right first time?

Very many thanks Taz

 

[Somerset Taz]

You are not going insane. Its a poor design and the simple and cheap answer so it never happens again is fit a relay between the black box and SC so the black box only ever triggers the relay and the relay protects the black box from over current. There is already one in there for the starter motor, you'd have thought they'd do the same for the SC .... doh

Hi Bruce - apologies for being lazy - I've had a think about the relay and it's quite a simple thing to do - I can use the duff controller to test my relay wiring as it's going to be switched to ground all the time. Regards Taz

 

[FatherTed]

The Speed Control Relay can be fixed, it's usually just a £5 transistor that blows. Don't throw anything away, PM me if you want me to take a look at it.

 

[volvopaul]

I've decided to start a new post on this issue. Over the past couple of seasons my Bavaria 29 Sport's port KAD32 has burnt out two supercharger controllers. After the first one I checked the wiring and had the clutch replaced. All was well - for a time - then mid season the controller failed the supercharger was on permanently and the breaker had popped. Whilst out of the water I rechecked and cleaned the wiring, had the alternator tested and fitted an isolator switch in the white cable on the supercharger clutch (both engines). All was ok for a time last season then, towards the end on the season, I noticed that whilst the supercharger was switched on (i.e. isolator switch to on) the supercharger was on permanently again and that the breaker had popped, again.

I think the supercharger controller has been fried (again!) - there's a short between pin 31 and S1. I'm in danger of falling into the "first sign of insanity - making the same mistake and expecting a different outcome"!
So I assume something other than the new clutch or alternator is frying my controller, but now I can't test the whole setup as I don't have a serviceable controller. Any tips on how to check the system, kick down sensor etc without a controller please? I'm not going to just swop bits from one engine to the other and risk the other engine's controller.
Also and possibly connected(?) on the same engine there's an irritating gremlin with the tacho. When running single engine the tacho reads ok but when the other engine is running too the tacho drops to about 1100 and stays there. Could the gurus suggest a possible cause of that issue so that I can fix it and eliminate it from possible link to my supercharger issue. This relatively simple system is driving me nuts! Cheers.

If the clutch is permanently engaged it’s the kick down switch that’s failed .

 

[Somerset Taz]

Thanks Paul,
I have the kick down switch off the boat and I can rig it up to power and see if it's failed on - and update the thread. I can't test it on the boat as the controller is u/s (a permanent short between pin 31 and S1) meaning the SC is always going to be on irrespective of any other input.
As suggested by BruceK I will be wiring in a relay to protect the new controller. I will also be cross-checking the SC clutch resistance (both ways) against my other engine to rule out the new clutch as a possible culprit. Hopefully it is the kick down sensor and not some phantom wiring issue. It would be great to nail it to one issue. Thanks again for your help. Regards Taz

 

[Somerset Taz]

Thanks to the 3 Wise Men!

Update: The problem with my Supercharger (SC) has been solved and fixed with the help of the three wise men!

Volvo Paul, thank you - It turns out that the proximity sensor was u/s as you predicted. Not wanting to cough up £200-300 for a volvo replacement I eventually sourced a Pepperl and Fuchs alternative and with an easy DIY mounting modification and then splicing the cable to the original connector got it to work (£50 from Kempston Controls see attached photos).

BruceK, thank you. Wired in a relay as you suggested – works a dream and now that the controller is remote from the SC coil, any issues with the coil in the future should not fry the controller.

Father Ted, thank you – my new best friend! Father Ted has modelled the SC circuitry and can diagnose controller issues. Best of all he knows how to repair those that get fried. He fixed both my u/s controllers and provided sage advice during my quest to source an alternative proximity sensor. Check out his excellent You Tube video demonstrating the KAD SC circuitry.

A note on the SC clutch coil. As a little experiment I managed to build/rewind a SC coil and insert it into the housing from the one that was burnt out. A little fiddly, but with a little patience it can be done in a couple of hours. Also, when I spliced my DIY coil to the original Volvo lead I noticed that the integral diode was u/s. It had shorted and this gave a 0 ohm reading on my coil when my rewound coil was perfectly ok at 3.4 ohms. Moral of this is before thinking your SC coil is u/s check the diode. A DIY diode replacement costs pennies – much cheaper than a full SC clutch kit from Volvo!

Sorry for the long summary, but a happy ending is worth sharing.

 

[Mr Googler]

Thanks to the 3 Wise Men!

Update: The problem with my Supercharger (SC) has been solved and fixed with the help of the three wise men!

Volvo Paul, thank you - It turns out that the proximity sensor was u/s as you predicted. Not wanting to cough up £200-300 for a volvo replacement I eventually sourced a Pepperl and Fuchs alternative and with an easy DIY mounting modification and then splicing the cable to the original connector got it to work (£50 from Kempston Controls see attached photos).

BruceK, thank you. Wired in a relay as you suggested – works a dream and now that the controller is remote from the SC coil, any issues with the coil in the future should not fry the controller.

Father Ted, thank you – my new best friend! Father Ted has modelled the SC circuitry and can diagnose controller issues. Best of all he knows how to repair those that get fried. He fixed both my u/s controllers and provided sage advice during my quest to source an alternative proximity sensor. Check out his excellent You Tube video demonstrating the KAD SC circuitry.

A note on the SC clutch coil. As a little experiment I managed to build/rewind a SC coil and insert it into the housing from the one that was burnt out. A little fiddly, but with a little patience it can be done in a couple of hours. Also, when I spliced my DIY coil to the original Volvo lead I noticed that the integral diode was u/s. It had shorted and this gave a 0 ohm reading on my coil when my rewound coil was perfectly ok at 3.4 ohms. Moral of this is before thinking your SC coil is u/s check the diode. A DIY diode replacement costs pennies – much cheaper than a full SC clutch kit from Volvo!

Sorry for the long summary, but a happy ending is worth sharing.

2 wise men….and one unlucky sod that has replaced many things before finding a cheap fix

 

[FatherTed]

Father Ted, thank you – my new best friend! Father Ted has modelled the SC circuitry and can diagnose controller issues. Best of all he knows how to repair those that get fried. He fixed both my u/s controllers and provided sage advice during my quest to source an alternative proximity sensor. Check out his excellent You Tube video demonstrating the KAD SC circuitry.

Electronics repair is something I have done for more than 30 years, so I put my mind into testing the controller and mapping out the circuit diagram in order to repair them as a hobby and to keep them out of the waste bin.

Here is the video showing how I test it. If anyone wanted to replicate the setup I can let you know what the parts are.

 

[petem]

Thanks to the 3 Wise Men!

Update: The problem with my Supercharger (SC) has been solved and fixed with the help of the three wise men!

Volvo Paul, thank you - It turns out that the proximity sensor was u/s as you predicted. Not wanting to cough up £200-300 for a volvo replacement I eventually sourced a Pepperl and Fuchs alternative and with an easy DIY mounting modification and then splicing the cable to the original connector got it to work (£50 from Kempston Controls see attached photos).

BruceK, thank you. Wired in a relay as you suggested – works a dream and now that the controller is remote from the SC coil, any issues with the coil in the future should not fry the controller.

Father Ted, thank you – my new best friend! Father Ted has modelled the SC circuitry and can diagnose controller issues. Best of all he knows how to repair those that get fried. He fixed both my u/s controllers and provided sage advice during my quest to source an alternative proximity sensor. Check out his excellent You Tube video demonstrating the KAD SC circuitry.

A note on the SC clutch coil. As a little experiment I managed to build/rewind a SC coil and insert it into the housing from the one that was burnt out. A little fiddly, but with a little patience it can be done in a couple of hours. Also, when I spliced my DIY coil to the original Volvo lead I noticed that the integral diode was u/s. It had shorted and this gave a 0 ohm reading on my coil when my rewound coil was perfectly ok at 3.4 ohms. Moral of this is before thinking your SC coil is u/s check the diode. A DIY diode replacement costs pennies – much cheaper than a full SC clutch kit from Volvo!

Sorry for the long summary, but a happy ending is worth sharing.

Chapeau for finding a green replacement!

 

[petem]

Electronics repair is something I have done for more than 30 years, so I put my mind into testing the controller and mapping out the circuit diagram in order to repair them as a hobby and to keep them out of the waste bin.

Here is the video showing how I test it. If anyone wanted to replicate the setup I can let you know what the parts are.

Great video

 

[New Boater]

Hello Taz,

Is there any way you can share your relay instal with me? Bearing in mind I am a van driver and have next to zero electronics knowledge!!

I can solder though so I have a fighting chance.

Just blown a speed control module. Will get another one (and will check clutch) but would love to avoid future failure.

Cheers

NB

 

[Somerset Taz]

Hello Taz,

Is there any way you can share your relay instal with me? Bearing in mind I am a van driver and have next to zero electronics knowledge!!

I can solder though so I have a fighting chance.

Just blown a speed control module. Will get another one (and will check clutch) but would love to avoid future failure.

Cheers

NB

Hi NB, firstly I would recommend asking FatherTed if he is still repairing Controllers. If he is, and can repair yours, it will save you a fortune! I would also point you to my recommendation to check the diode that is part of the supercharger lead. I've attached a couple of diagrams/schematics for the relay. I managed to squeeze the relay into the engine control black box. Since fitting the relay I've had no issues. Regards Taz

 

[New Boater]

Thanks Taz,

I can’t download the PDF so will try it on the PC when I get back.

Great help mate. Cheers again.

I am going to buy myself a nice soldering iron and a pair of specs and stuck in to repairing things instead of throwing them away.

Better get a fire extinguisher too.