Fault finding query- various components - UK Vintage Radio Repair and Restoration Discussion Forum

The Philpott · 4th Apr 2020, 12:21 pm

This is a central locking control module. A rogue current drain exists but I can't exclude the problem being the micro-switch which is elsewhere (and therefore drifting outside forum subjects)

I would like to ask-
1. Are the green 'resistor things' actually inductors?
2. Out of the following components where should they lie in the list of suspects?

-3 silicon diodes
-3 germanium diodes
-3 caps, One 100uF 'SME', Two 3.3uF (orange/brown in colour)
-2 transistors- BC 337-40
-11 inductors (?)
-2 relays
-Main chip- Toshiba 14 pin chip- TC4030BP 8536HB

(With 12v input 9v is present at the 'Zu' (closed) output terminal all the time- I have yet to fathom whether this is correct function.)

Dave

Station X · 4th Apr 2020, 12:38 pm

Gentlemen. Can we keep this thread on topic please. No discussions about vehicles in general or central locking systems.

Thank you.

TonyDuell · 4th Apr 2020, 1:14 pm

I would think the green things are resistors. It would be unusual to have a digital circuit with 11 inductors and no resistors.

The main IC may well be a 4030 quad XOR gate (in the 4000 series CMOS range). I have no idea what the difference between the 4030 and 4070 is, the Philips datasheets I have are indentical (apart from the number on the top) and I've seen ICs marked with both numbers.

How large is the excess current drain? Enough to suggest one of the relays is energised all the time? Or small enough that it's a leak through a capacitor or something?

Excess supply current could be a leaky decouplng capacitor (Is that 100uF across the supply, for example). It could be damage to the IC. That's what I would check first.

eaglework · 4th Apr 2020, 1:24 pm

I agree with Tony the green things are going to be resistors.
If its a single sided board you could consider reverse engineering the circuit to see if that is of any help in understanding how it operates.
All the components look to be standard with nothing exotic so you could consider testing each one after removing it from the PCB.
I had a similar issue on one of the family cars and it took some detective work even with OEM wiring diagrams to discover its was the alarm horn buried under the inner wing drawing 70ma when it should have been much less.

The Philpott · 4th Apr 2020, 1:48 pm

Thanks. The current drain is unknown but significantly high. It's very intermittent and coincides with one or more (remote) solenoids trying but failing to 'throw'.

(There is easy access to this module so my logic was to exclude this from the equation before looking for the more likely but more inaccessible gremlins elsewhere- which we won't mention)

Thankyou for allowing the thread Graham,

The PCB is indeed single sided although two of the diodes are hidden underneath the relays!

Dave

HamishBoxer · 4th Apr 2020, 2:13 pm

Just a point and with all respect to what Graham has said I had a problem with locking and just followed instructions and re set the key fob.

Going back to the resistors you queried,what do they read and would that tie up with the markings ?They certainly look like resistors.

What I should have said is it drawing too much current for certain,not just a red herring for another fault.

60 oldjohn · 4th Apr 2020, 2:51 pm

Quote:

Originally Posted by The Philpott

Thanks. The current drain is unknown but significantly high. It's very intermittent and coincides with one or more (remote) solenoids trying but failing to 'throw'.

Dave

I wonder if is something as simple as high resistance on the relay contacts, they look easily accessible to clean.

John.

The Philpott · 4th Apr 2020, 9:16 pm

This is an old stand-alone system, without IR transmit/receive, and outside of the controller itself is entirely electro-mechanical.
I will check and polish up the relay contacts first, then pull the largest cap. out of circuit and test it.

The system was powering up at random, so the current was not excessive as such, merely unwanted and discharging the battery.

Dave

Terry_VK5TM · 5th Apr 2020, 1:03 am

The smaller caps should be tested as well.

If there is no coating on the bottom of the pcb (as in waterproofing) it is possible that slight damp and associated dust could cause anomalous things to happen as the cmos inputs will be high impedance.

The Philpott · 5th Apr 2020, 1:16 pm

Large cap. tested out of circuit, the meter says it's OK. Ditto, the smaller caps.
The relay windings both come out at 69 ohms so there shouldn't be weakness through shorted turns. There is continuity through the contacts, but will clean them to be sure. The static contacts have a stippled appearance (like the top of a 'fruit gum') from new, I am reluctant to remove too much material from them as there must be a reason for the texture.

The underside of the pcb is not coated. I will check to see if any conductive deposit exists.

4th Apr 2020, 12:21 pm	#1
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Fault finding query- various components This is a central locking control module. A rogue current drain exists but I can't exclude the problem being the micro-switch which is elsewhere (and therefore drifting outside forum subjects) I would like to ask- 1. Are the green 'resistor things' actually inductors? 2. Out of the following components where should they lie in the list of suspects? -3 silicon diodes -3 germanium diodes -3 caps, One 100uF 'SME', Two 3.3uF (orange/brown in colour) -2 transistors- BC 337-40 -11 inductors (?) -2 relays -Main chip- Toshiba 14 pin chip- TC4030BP 8536HB (With 12v input 9v is present at the 'Zu' (closed) output terminal all the time- I have yet to fathom whether this is correct function.) Dave Attached Thumbnails

4th Apr 2020, 12:38 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,286	Re: Fault finding query- various components Gentlemen. Can we keep this thread on topic please. No discussions about vehicles in general or central locking systems. Thank you. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

4th Apr 2020, 1:14 pm	#3
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,208	Re: Fault finding query- various components I would think the green things are resistors. It would be unusual to have a digital circuit with 11 inductors and no resistors. The main IC may well be a 4030 quad XOR gate (in the 4000 series CMOS range). I have no idea what the difference between the 4030 and 4070 is, the Philips datasheets I have are indentical (apart from the number on the top) and I've seen ICs marked with both numbers. How large is the excess current drain? Enough to suggest one of the relays is energised all the time? Or small enough that it's a leak through a capacitor or something? Excess supply current could be a leaky decouplng capacitor (Is that 100uF across the supply, for example). It could be damage to the IC. That's what I would check first.

4th Apr 2020, 1:24 pm	#4
eaglework Pentode Join Date: Jun 2017 Location: Alton, Hampshire, UK. Posts: 159	Re: Fault finding query- various components I agree with Tony the green things are going to be resistors. If its a single sided board you could consider reverse engineering the circuit to see if that is of any help in understanding how it operates. All the components look to be standard with nothing exotic so you could consider testing each one after removing it from the PCB. I had a similar issue on one of the family cars and it took some detective work even with OEM wiring diagrams to discover its was the alarm horn buried under the inner wing drawing 70ma when it should have been much less.

4th Apr 2020, 1:48 pm	#5
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Re: Fault finding query- various components Thanks. The current drain is unknown but significantly high. It's very intermittent and coincides with one or more (remote) solenoids trying but failing to 'throw'. (There is easy access to this module so my logic was to exclude this from the equation before looking for the more likely but more inaccessible gremlins elsewhere- which we won't mention) Thankyou for allowing the thread Graham, The PCB is indeed single sided although two of the diodes are hidden underneath the relays! Dave

4th Apr 2020, 2:13 pm	#6
HamishBoxer Dekatron Join Date: Aug 2007 Location: W.Butterwick, near Doncaster UK. Posts: 8,931	Re: Fault finding query- various components Just a point and with all respect to what Graham has said I had a problem with locking and just followed instructions and re set the key fob. Going back to the resistors you queried,what do they read and would that tie up with the markings ?They certainly look like resistors. What I should have said is it drawing too much current for certain,not just a red herring for another fault. __________________ G8JET BVWS Archivist and Member V.M.A.R.S

4th Apr 2020, 9:16 pm	#8
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Re: Fault finding query- various components This is an old stand-alone system, without IR transmit/receive, and outside of the controller itself is entirely electro-mechanical. I will check and polish up the relay contacts first, then pull the largest cap. out of circuit and test it. The system was powering up at random, so the current was not excessive as such, merely unwanted and discharging the battery. Dave

5th Apr 2020, 1:03 am	#9
Terry_VK5TM Nonode Join Date: Oct 2010 Location: Tintinara, South Australia, Australia Posts: 2,339	Re: Fault finding query- various components The smaller caps should be tested as well. If there is no coating on the bottom of the pcb (as in waterproofing) it is possible that slight damp and associated dust could cause anomalous things to happen as the cmos inputs will be high impedance. __________________ Terry VK5TM https://www.vk5tm.com/

5th Apr 2020, 1:16 pm	#10
The Philpott Dekatron Join Date: Aug 2016 Location: Colchester, Essex, UK. Posts: 4,104	Re: Fault finding query- various components Large cap. tested out of circuit, the meter says it's OK. Ditto, the smaller caps. The relay windings both come out at 69 ohms so there shouldn't be weakness through shorted turns. There is continuity through the contacts, but will clean them to be sure. The static contacts have a stippled appearance (like the top of a 'fruit gum') from new, I am reluctant to remove too much material from them as there must be a reason for the texture. The underside of the pcb is not coated. I will check to see if any conductive deposit exists.