Circuit Board Repairs?
Thread Starter
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
I see 6 semiconductor parts on that circuit.
2 signal doides behind the cap in the circle
1 IC mc14069u hex inverter
1 zener diode?? with the blue stripe
1 rectifer diode wth the silver stripe
1 transistor ??
From my experience the transistors are the hardest to replace as the parts # is some sort of in house general motors #. You need to find a good part and figure out what it is NPN,PNP,gain,pinout or in some cases trace the circuit.
The timer you have shown does not look like the timer for a C3 ,is it from your 89? If so, you may have better luck asking your question in the C4 forum.
If you want I can look at your timer but sending stuff across the boarder is a PITA.
Cheers
Dale
2 signal doides behind the cap in the circle
1 IC mc14069u hex inverter
1 zener diode?? with the blue stripe
1 rectifer diode wth the silver stripe
1 transistor ??
From my experience the transistors are the hardest to replace as the parts # is some sort of in house general motors #. You need to find a good part and figure out what it is NPN,PNP,gain,pinout or in some cases trace the circuit.
The timer you have shown does not look like the timer for a C3 ,is it from your 89? If so, you may have better luck asking your question in the C4 forum.
If you want I can look at your timer but sending stuff across the boarder is a PITA.
Cheers
Dale
Thread Starter
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Courtesy Light Delay Timer ?
Those aren't diodes, thos are ceramic capacitors. the diode is the small black cylindircal device in the front with two leads and the silver line. t5hose type of caps don't usualy fail, they look dirty to me, not bad. i could replace every componant on the board in about 10 mins. i'll be happy to look at it if you'd like, i'll send my address later,, no charge. C.
Hey Chris:
Did the Courtesy Light Delay Timer show up in the mail yet? Let me know....
Safety Car
Joined: Jun 2002
Posts: 4,770
Likes: 2,515
From: Buckeye, AZ
St. Jude Donor '12-'13
I agree with others above....if you know the diode is bad why would you pay someone to do the repair? Boards made in the era were typically only single layer. You can safely desolder and fix with a low wattage iron.
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
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Thread Starter
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Advanced
Joined: Nov 2007
Posts: 51
Likes: 0
From: Louisville ky
I have a fuse popping (dash lights/parking lights), my battery light and a buzzer go off with acceleration/deceleration, and my temperature gauge does not appear to be working. I suspect it may be the center console circuit board. What is the best way to check this before I start taking the center console out and buying parts unecessarily? Man I hate electric problems...
Thread Starter
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
I have a fuse popping (dash lights/parking lights), my battery light and a buzzer go off with acceleration/deceleration, and my temperature gauge does not appear to be working. I suspect it may be the center console circuit board. What is the best way to check this before I start taking the center console out and buying parts unecessarily? Man I hate electric problems...
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Here is the schematic for the C4 light timer, firgure it out? 
, both circiuts i looked at operate, well, strangly. discreet analog circiut design is an art, but they do work. this one had some cold solder joints and the output transistor was questionable. So it will be replaced, and off it wil go. You'll be happy with this one pete, works perfect. 
(zener is 5.7v btw, for you elec gurus)
, both circiuts i looked at operate, well, strangly. discreet analog circiut design is an art, but they do work. this one had some cold solder joints and the output transistor was questionable. So it will be replaced, and off it wil go. You'll be happy with this one pete, works perfect. (zener is 5.7v btw, for you elec gurus)
Last edited by RunningMan373; Jan 18, 2008 at 05:43 AM.
Burning Brakes
Joined: Aug 2004
Posts: 837
Likes: 2
From: Derry NH
I feel dumb now. I have an EE degree, but none of my jobs have ever required circuit analysis. I used to enjoy it, also...
Thanks for exercising that part of my brain where zener diodes once held a special place!
Thanks for exercising that part of my brain where zener diodes once held a special place!
Melting Slicks
Joined: May 2007
Posts: 3,246
Likes: 4
From: Bay Area CA
Ok, all done. interesting thing, i was going to change the output transistor, but on testing, the original one has about 40% less on resistance, and stays significantly cooler. Tested at 3 amps for 30 mins, stays just warm. good. Also changed the electorlyt Cap, they do go bad.
on resistance for new trans gives about 1.65Watt of power disipated
on resistance of original trans gives about 1.08Watt of power, means it stays 40% cooler. Stayed withthe original trans, it's a very good part.
Here she is, ready to ship.
on resistance for new trans gives about 1.65Watt of power disipated
on resistance of original trans gives about 1.08Watt of power, means it stays 40% cooler. Stayed withthe original trans, it's a very good part.
Here she is, ready to ship.
Thread Starter
Slingshot
Joined: Dec 2001
Posts: 3,817
Likes: 24
From: Charlotte NC
Thank you, thank you!
WOW ! Your the MAN, Chris. I sincerely appreciate all your help with solving this C4 electrical problem. I'm sure that many others on the Forum will benefit from your fine work here. WELL DONE
