VN05N removal (she's alive!)

deian · Unread post by **deian** » 03 Jan 2010, 00:37

just finished soldering, i just put the naked board on to hear some life, and it seems there is life out there, i could hear both electrovalves buzzing, had to open the door, then it buzzed, and then it stopped after 30 seconds, as it should,

in the soft mode i saw just now (no engine, so the height wasn't perfect) it wasn't that much different , i will try it more tomorrow after starting the engine to get the height corrected and a good bleed of the system, chances are it will need new centre spheres, i was kind of hoping to feel a noticeable difference, oh well, glad i got this far

but yes, it seems to work...

i'm not too sure the solenoid sounds are as smooth and healthy as they should be, they did change tone (higher) a little after a few seconds, is it possible for the solenoids to be half open, or stuck closed?

i need an oscilloscope, no idea how to use one, and no idea where to find one (bar the uni in bangor, i have no contacts there), and then i don't know how to connect it up

well so far, thanks for all your help and advice and support, great forum we have here, i won't show a picture of the soldering in case i jinx myself, it's not that much better but i did use less solder

oh did i say happy new year to you all?

Regards,
Deian

Unread post by **CitroJim** » 03 Jan 2010, 07:23

Well done Dei, great stuff!

An oscilloscope can be useful as it'll show duff diodes in an instant but your ears can also tell too...

This is a typical waveform with good diodes:

If the diodes are bad, the waveform will look "ragged" and show ringing on the transitions. Sadly I have no picture of a bad waveform...

Generally if the diodes are bad, you'll not hear a positive click from the valves when they turn off after 30s.

Basically you should hear, as you open the door, click-hummmmmmmm and as you close the door the hummmmmm should carry on for 30s and end with a click. If you don't hear the ending click, the diodes are likely to be gone. Note that the ending click is louder and more pronounced when there is good hydraulic pressure present.

Looking forward to the next instalment

Unread post by **Peter.N.** » 03 Jan 2010, 08:51

Well done deian

HDI · Unread post by **HDI** » 03 Jan 2010, 09:40

CitroJim wrote:Well done Dei, great stuff!

Basically you should hear, as you open the door, click-hummmmmmmm and as you close the door the hummmmmm should carry on for 30s and end with a click. If you don't hear the ending click, the diodes are likely to be gone. Note that the ending click is louder and more pronounced when there is good hydraulic pressure present.

Looking forward to the next instalment

That comment is very useful. Thats exactly what I hear on mine so hopefully the diodes are ok.

Scopes are indispensable , couldn't work without mine. The older types can be found on ebay for cheap now that the new TFT screen , very high bandwidth types are available. I would recommend Tektronix.
I actually just upgraded my old scope to a nice Telequipment D83 off ebay for £35 !!

Mandrake · Unread post by **Mandrake** » 03 Jan 2010, 10:29

deian wrote: in the soft mode i saw just now (no engine, so the height wasn't perfect) it wasn't that much different , i will try it more tomorrow after starting the engine to get the height corrected and a good bleed of the system, chances are it will need new centre spheres, i was kind of hoping to feel a noticeable difference, oh well, glad i got this far

If the engine hasn't been running for some time, there won't be any change in the stiffness when the electrovalves turn on - because the high pressure hydraulic supply is necessary to activate the main shuttle valve in the hydractive control block.

The electrovalve turning on doesn't directly open the main valve, it just connects a path between the high pressure supply and one side of the shuttle valve - if the pressure isn't available, nothing will happen.

If the electrovalves are humming happily, chances are you have fixed it, and it will work fine once the engine is running and state of the hydractive spheres have been verified

I think it's normal for the humming to sound a bit "raggy", mine always did, and the pitch and character of the noise changed quite a lot with small variations in battery voltage. As long as it's a continuous hum I wouldn't worry about it too much.

Regards,
Simon

xmexclusive · Unread post by **xmexclusive** » 03 Jan 2010, 11:34

Hi Dei

Glad you seem to have a working board now.
Can you clear up one point for me.
Which of the boards have you got repaired, your original or the one from Paul? What components have you actually changed?
When you checked the second board you mentioned that the BUZ11's on both boards were similarly heat damaged and you did not have a replacement. Sorry to push for detail but it would help complete things.

Regards

John

deian · Unread post by **deian** » 03 Jan 2010, 12:25

Hi,

the only thing i've changed on paul's board is the single burned transistor, that is it, less solder, and using a weller iron, I haven't attached the transistor to the backing of the 'wing' as the aluminium backing has come off the fibreglass (it didn't on mine), i think it could be better unattached for now (more airflow?), but if it breaks down again i know why now, i should note that the soldering i did last night took nearly two hours from detaching and reattaching, it really isn't a job for the faint hearted and patience is needed in abundance

i didn't change any buz11's I don't have any yet, not sure i will order some, I now have 2 vn05n's remaining.

when i checked both ecu's they were both checked AFTER I did the diode fix on the electrovavle cables

as for the damage on the BUZ11, here is a picture:

finally, here are the two identical boards:

i may well invest in an oscilloscope if they can be had for that cheap, i would certainly need one for the future

the electrovalves are happily humming, and there is a prominent click when they switch off, so all is good so far, gonna pack the board back up in the case, and plug it back in, and do some bleeding now and height correcting now

again, you guys have been great, your help is very much appreciated and if there's anything else i can explain to you then so let me know

it's all great fun for the "hobbyist" amongst us, i enjoy nothing better than to be messing about with electronics and mechanical stuff, i love fixing things, and i suspect almost everyone here enjoyed fiddling as much as i do, thats why these hydraulic citroens appeal to some of us so much.

oh and just for the record, i fudge things up often (as you all now know), and i believe it's ok to do so, there no other way to learn

Unread post by **Peter.N.** » 03 Jan 2010, 13:06

HDI

Sadly the fact that you can hear the the electrovalves humming does not necessaraly indicate that your diodes are OK. You should hear 'clonk - hum' when you open the door but you should hear another 'clonk' when the valve closes after about 30 seconds, if you dont it can mean that the valves opened but didn't remain open, which is what happens when the diodes need replacement.

Its very easy to check if the system is working, with a door open you should have 4" - 6" of movement on the suspension, assuming the centre spheres are OK, shut the door and keep bouncing, when the valve shuts you will be able to feel a distinct stiffening of the suspension and a considerable reduction in movement.

Peter

deian · Unread post by **deian** » 03 Jan 2010, 16:05

Well I put all back together, started the engine did some citrobeotics and a depressure (with the screw) and it does 'seem' different, I think the spheres need changing and a good dose of lhm cleaner... when the time is right (not in winter).

And the ride does seem more wallowy so I would say it works, it does make more of 'stamping' noise than a clonk or a click, when opening and closing so i assume it's working fine.

thanks for all your help. Hopefully this thread will be a reference for the future on how and how not to fix hydractive 2 ecu's

xmexclusive · Unread post by **xmexclusive** » 03 Jan 2010, 16:28

Hi Dei

Pleased it now is working.
From your photos I think the BUZ11 is good on the board that you are now using. The marks on its metal block are just from the original factory soldering. I do not think it matters about soldering the body of the VN05N's back onto the wing other than making sure that the metal block on the device is well clear of the ECU metal case. If you look carefully at the two "wings" for these components you will see that only the BUZ11/L4705 one is a heatsink comprising 1mm thick aluminium nearest the main pcb then a thin insulating layer and finally pcb copper film to solder the devices too.
On the VN05N side the wing is just 1 mm thick PCB fiberglass sheet with 3 thin pcb copper contact film oblong shapes to solder the devices to so cannot provide any real heatsinking effect.

John

HDI · Unread post by **HDI** » 03 Jan 2010, 17:04

Peter.N. wrote:HDI

Sadly the fact that you can hear the the electrovalves humming does not necessaraly indicate that your diodes are OK. You should hear 'clonk - hum' when you open the door but you should hear another 'clonk' when the valve closes after about 30 seconds, if you dont it can mean that the valves opened but didn't remain open, which is what happens when the diodes need replacement.

Its very easy to check if the system is working, with a door open you should have 4" - 6" of movement on the suspension, assuming the centre spheres are OK, shut the door and keep bouncing, when the valve shuts you will be able to feel a distinct stiffening of the suspension and a considerable reduction in movement.

Peter

I do hear exactly as you describe but I haven't done the travel check yet , will have the opportunity for that tomorrow. Thanks.