L series clock

Cliff R · Post by **Cliff R** » Fri Dec 02, 2011 5:38 am

Is there anyone out there keen/interested enough with a spare L series clock who would like to unclip the back panel of the clock to open up the electrics and maybe let me know the colours of the resistor which is to the right hand side of the 3 push buttons.
Next to the right hand push button is a diode (clear/red looking thing) then the resistor I need to know the colour of or better yet its value for someone who knows what they are looking at. There is another resistor and diode and a couple of capacitors beside this but it is this first resistor (the biggest one) I am interested in.
Mine has overheated at some point and its colours and now stuffed so I dont know it rating.
Unless of course someone has a scematic diagram for the clock in which case this will/show the value of the resistor.
I know going to a wreckers to get another one would be easier but I like a challenge (sometimes anyway)

revmax · Post by **revmax** » Fri Dec 02, 2011 4:03 pm

must be common problem my old L seris did the same.
I have a wreck out the back and will have a look at some time soon but if someone else knows please post.

GOD · Post by **GOD** » Fri Dec 02, 2011 5:21 pm

The colour bands on mine are burnt, but the multimeter says it's 75 ohms.

Each of the components also has a label printed on the PCB. That resistor is R750, which seems to mean 75x10^0. The other, undamaged, resistors on the board have similar labels corresponding to their measured values.

Dane.

Post by **Alex** » Fri Dec 02, 2011 5:27 pm

i tried to fix mine once, as soon as the soldering iron touched it, the tracks all lifted from the board.

that clock was the bain of my life for a little while when i was trying to fix it!

alex

FROG · Post by **FROG** » Fri Dec 02, 2011 5:28 pm

What causes the frying? Is it too small a rating for the job its doing ?

Or is another component failing ?

just wondering if it was possible to fix the underlying problem

Post by **Alex** » Fri Dec 02, 2011 5:47 pm

i think its the solder joints getting old and drying out, hence not conducting the current as well making the resistor work harder?

i got mine working and youd be suprised how hot that bloody resistor gets!

YouTube · Post by **El_Freddo** » Fri Dec 02, 2011 10:20 pm

Alex wrote:i think its the solder joints getting old and drying out, hence not conducting the current as well making the resistor work harder?

Yeah I agree with that! I've soldered a mate's one up. I've been lucky with mine so far.

Any joints that look cracked, just re-heat the joint and add a little bit of solder if needed...

Cheers

Bennie

Cliff R · Post by **Cliff R** » Sat Dec 03, 2011 6:29 am

Thanks everyone for your comments.
Definately looks to be a common problem.
I will try a 75 Ohm resistor and see what happens.
Should have looked closer myself and I would have noticed the R750 2W marked on the board - Doh !!

Cliff R · Post by **Cliff R** » Sat Dec 03, 2011 12:16 pm

What's this world coming to. Dick Smith doesnt sell resistors any more !!
Have to go through my collection and see what I have.

Battlewagon · Post by **Battlewagon** » Sat Dec 03, 2011 2:04 pm

Try Jaycar for the resistors.
They have an online store somewhere.

Silverbullet · Post by **Silverbullet** » Sat Dec 03, 2011 2:08 pm

Yeah Dick smiths have moved to consumer electronics, they don't sell DIY electronics stuff anymore. Jaycar is the place for all things Dick smiths used to be.

YouTube · Post by **El_Freddo** » Sun Dec 04, 2011 9:37 pm

Cliff R wrote:Thanks everyone for your comments.
Definately looks to be a common problem.
I will try a 75 Ohm resistor and see what happens.
Should have looked closer myself and I would have noticed the R750 2W marked on the board - Doh !!

Are you sure the resistor is dud? The common problem is a solder joint that's "dried out" and not keeping the connection properly or at all.

I'd try soldiering the joint near the resistor, plug it into the subi and see if it works, if not then go down the replace the resistor route.

Cheers

Bennie

GOD · Post by **GOD** » Sun Dec 04, 2011 10:28 pm

^ What Bennie said. SHould have mentioned that in my first reply.

I've resoldered mine once or twice before, but it keeps overheating that resistor. If you're keen maybe try two x 1500 ohm 2W resistors in parallel or get a little bit fancy with heatsinks. Or get a watch

Dane.

Cliff R · Post by **Cliff R** » Fri Dec 09, 2011 8:26 am

OK so the clock saga continues.
During the week I collected 4 L series clocks. My original one (92 model) an 88 model, a 91 model and a 93 model.
All are the same except the 88 model which has the same wiring but a different plug.
On all the clocks the wiring is red (lamp) blue (battery) yellow (accessories) and black (ground)
I am not electrical by trade (just by interest) but to my way of thinking if I was to connect 12vdc positive up to the blue (battery) and the yellow (accessories) and negative to the black (ground) the clock should work.
Before I go and do this is my way of thinking right ?
I cant find in either the Gregorys or the Haynes manuals any reference in the schematics to clock wiring so cant think of any other options.
The 12vdc can be supplied by either a dual tracking power supply good from 0 to 30vdc or a mini lab with a digital regualted power supply. Either way the voltage can be controlled very accurately.
Any thoughts before I blow something up ?

YouTube · Post by **El_Freddo** » Fri Dec 09, 2011 4:22 pm

Cliff R wrote:Any thoughts before I blow something up ?

Nope, you've got my permission to blow something up!

What you've said above with the wiring seems correct, including the battery trick - but I ask, why not just hook it back in the subi and give it a go??

Cheers

Bennie

FROG · Post by **FROG** » Fri Dec 09, 2011 5:36 pm

GOD wrote:I've resoldered mine once or twice before, but it keeps overheating that resistor. If you're keen maybe try two x 1500 ohm 2W resistors in parallel or get a little bit fancy with heatsinks

Dane.

thats what I was interested in! The two resistors in parallel , be interested to see if that cools things down , resistors are cheap and would be good for a definate fix and not hard to do

Cliff R wrote:OK so the clock saga continues.
During the week I collected 4 L series clocks. My original one (92 model) an 88 model, a 91 model and a 93 model.
All are the same except the 88 model which has the same wiring but a different plug.
On all the clocks the wiring is red (lamp) blue (battery) yellow (accessories) and black (ground)
I am not electrical by trade (just by interest) but to my way of thinking if I was to connect 12vdc positive up to the blue (battery) and the yellow (accessories) and negative to the black (ground) the clock should work.
Before I go and do this is my way of thinking right ?
I cant find in either the Gregorys or the Haynes manuals any reference in the schematics to clock wiring so cant think of any other options.
The 12vdc can be supplied by either a dual tracking power supply good from 0 to 30vdc or a mini lab with a digital regualted power supply. Either way the voltage can be controlled very accurately.
Any thoughts before I blow something up ?

Jeez you found three others, that gives you opportunity to blow things up and still have a clock

El_Freddo wrote:Nope, you've got my permission to blow something up!
Cheers

Bennie

I concur just follow proper OH and S

Cliff R · Post by **Cliff R** » Fri Dec 09, 2011 6:22 pm

Blast !!
Typed in a nice long update reply to everyone and it didnt go through.
Probably better for all concerned as I can touch type and all my e mails are generally a one page document.
Here is a re typed basic message as a 2nd attempt.
Tryed plugging the clocks into the car and (see below for results)
Also by the time we get 4 kids under 10 into bed it is dark so the power supply in the garage is a nicer option.
Plugged all 4 clocks into the car and they all provided a very faint display. Pushed the various clocks buttons (Set/Minute/Hour) and the display got brighter (normal) and when the minute button was pushed the display brightened and the hour figure ticked over an hour at a time. (no idea why)
Tryed all the clocks on the power supplied and the same thing happened.
Two options I can think of at the moment.
1. all 4 clocks are stuffed
2. my cars wiring has a problem
Point 2 is not really an opiton as the same symptoms exist when I use the power supply.
I am still looking for a schematic for the clock showing how it fits into the cars wiring system.
Will pick a clock (any clock) and resolder everything.
Noted from the 88 model clock that the 75 ohm resistor was originally blue in colour, 1st band is Violet, 2nd bank is Green, 3rd band is Black and the 4th band appears to also be Black. This 4th band colour does not make sense as is should be nothing or silver or gold. Maybe originally it was gold ?

L-nutter · Post by **L-nutter** » Sat Dec 10, 2011 7:13 am

Hi Guys,

I went through this about 5 years ago, so forgive the brain if it's a bit rusty

I had 2 L's with poor clocks so went to the effort to install 75 ohm 5 watt resistors in place of the 2W ones. The resistors were still quite hot in normal operation considering that the higher wattage should have mean they were less hot!

They both worked great for about 2-4 weeks until the same thing happened again. I think the end diagnosis was that the clock itself was just drawing too much current but would love to hear if you get yours going !!!

Your correct about the 4th band, it should be generally silver or gold, but i've found resistors in cars are not always marked as expected.

From memory too, the red wire (lamp) is just to dim the display, i think it was 'normal-daytime' brightness when this was 0 volts....does this sound right?

last bit...had a mate with an 85 L with the amber clock and was never a problem!

Cheers, Dougie

Cliff R · Post by **Cliff R** » Sat Dec 10, 2011 9:17 am

Interesting !!
I think I can get a hold of a couple of 85 model clocks so may do this early next week.

YouTube · Post by **El_Freddo** » Sat Dec 10, 2011 10:04 pm

L-nutter wrote:...had a mate with an 85 L with the amber clock and was never a problem!

Well, to add to this, I've got an '88 L series that I've never had a clock issue with. I got the subi at 297k km, it's now at 462k km with many hours off offroading amongst it.

Still going strong.

Also, if you get a clock with an amber colour number set, apparently you can change the filter to the green one and vice versa.

Really I think it's just the luck of the draw.

Cheers

Bennie