Printed Circuit Question 79 K10

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

79K10Step

Junior Member
Joined
Sep 24, 2022
Posts
25
Reaction score
15
Location
TN
First Name
Bert
Truck Year
1979
Truck Model
K10
Engine Size
350
My problem is left turn indicator light is not working. All other gauges and lights working fine as most are new. On the back of the Printed Circuit Board the copper ribbon wire has a break in it wide enough that I will need to make a jumper. Question is how can I attach a jumper to this copper ribbon - Solder another piece of ribbon - silicone glue that conducts etc... I have some old Circuit boards just trying to figure the best way to fix as the copper ribbons on the PCB are very thin?
 

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
933
Reaction score
3,791
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
I believe LMC has circuit boards for your truck in stock now for less than $60. I had a 1980 GMC with the same left signal indicator issue.
 

ChuckN

Full Access Member
Joined
Nov 8, 2022
Posts
1,322
Reaction score
4,026
Location
Bellinham, WA
First Name
Chad
Truck Year
1981
Truck Model
C10
Engine Size
350
My problem is left turn indicator light is not working. All other gauges and lights working fine as most are new. On the back of the Printed Circuit Board the copper ribbon wire has a break in it wide enough that I will need to make a jumper. Question is how can I attach a jumper to this copper ribbon - Solder another piece of ribbon - silicone glue that conducts etc... I have some old Circuit boards just trying to figure the best way to fix as the copper ribbons on the PCB are very thin?
When I took apart my cluster to do the tach conversion, mine had a printed circuit failure at one point. He had taken a couple small screws drilled through the back of the green plastic, and homemade a couple terminals out of them, one on each side of the part that had gone bad. He put a jumper wire from one terminal screw the other other to bypass the broken part. It looked sketchy as hell. But it might have been fine.

I second the recommendation for just getting a new printed circuit. They’re cheap overall and if you are missing any gauges or a tach that you would like and are missing, would be an opportune time to do it since you’re already in there.
 

Rickf

Full Access Member
Joined
Jul 29, 2017
Posts
571
Reaction score
713
Location
Grafton NH
First Name
Rick
Truck Year
1974, 1954 & a 1937
Truck Model
K20
Engine Size
350
If plan "A" (new printed circuit) isn't an option, then what about going directly from the plug to the bulb?
 

Kiely

Member
Joined
May 27, 2019
Posts
41
Reaction score
44
Location
Michigan- Wyandotte
First Name
John
Truck Year
1974
Truck Model
C10 Custom Deluxe
Engine Size
454-4bbl
An easier fix is to use copper foil like they use doing stained glass lamps. The back side is sticky so it is easy to get it to stick to the circuit boar. To completely secure the fix, solder a little spot on each end of the repair.
 

RustyPile

Left on own accord
Joined
Oct 7, 2017
Posts
901
Reaction score
1,124
Location
Elkhart, TX
First Name
Nick
Truck Year
1983 GMC
Truck Model
1500
Engine Size
350 SBC
When I took apart my cluster to do the tach conversion, mine had a printed circuit failure at one point. He had taken a couple small screws drilled through the back of the green plastic, and homemade a couple terminals out of them, one on each side of the part that had gone bad. He put a jumper wire from one terminal screw the other other to bypass the broken part. It looked sketchy as hell. But it might have been fine.

I second the recommendation for just getting a new printed circuit. They’re cheap overall and if you are missing any gauges or a tach that you would like and are missing, would be an opportune time to do it since you’re already in there.
That would work very well only if the broken trace were a ground path.. The broken trace the OP has can't be repaired using that method.. I've repaired several broken traces by soldering a "bridge across the broken spot. Scrape the coating off down to shiny copper, but don't further damage the trace or cut through the plastic. Use a short piece of solid (not stranded) 20 - 28 gauge bare wire. Tin it very good and solder it across the break.. Don't use 100 watt "gun". A small 40 watt iron used for electronic work is best.
 

79K10Step

Junior Member
Joined
Sep 24, 2022
Posts
25
Reaction score
15
Location
TN
First Name
Bert
Truck Year
1979
Truck Model
K10
Engine Size
350
Thanks to all of you for the good suggestions. The reason I had not gone for the new circuit option was twofold - one the PCB's have many different options (knowing LMC has 78-80 w/out tach) excluding the obvious tach option which I don't have for example mine has 4wd indicator some don't mine has a clock some don't etc.. The second concern I have is attaching a new one and messing up something that works. I will try to jump it and if that fails I will go for a new one. I will not use my propane soldering iron or my strong electric one as suggested. A direct connection to the bulb from the plug may work also. Thanks again
 

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
933
Reaction score
3,791
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
I had an oil pressure gauge that wasn't reading on one of my trucks not long ago. I traced it to a bad Sending Unit Female Terminal/circuit board connection behind the gauge. So, with other jobs coming up and not wanting to tear the dash out again, I ran a wire from the main terminal attached to the gauge directly to the sending unit. Done and done.
Now, if I never get back to replacing that board and sell the truck, eventually someone else down the road will for whatever reason, have the dash opened up and have a "WTF" moment.
 

tadslc

Full Access Member
Joined
Jan 20, 2020
Posts
120
Reaction score
134
Location
Birmingham, AL
First Name
Tad
Truck Year
1981
Truck Model
C10
Engine Size
350 Blueprint
I believe LMC has circuit boards for your truck in stock now for less than $60. I had a 1980 GMC with the same left signal indicator issue.
I bought one of those circuit boards from LMC and was very disappointed in the quality. Typical Chinese junk. After I installed it 1/2 the lights didn't work. Found nothing was really wrong with my old one so I just cleaned it up and reinstalled.
I'd do whatever it took to get your original board working.
 

Goldie Driver

Full Access Member
Joined
Mar 19, 2018
Posts
4,042
Reaction score
6,634
Location
Houston, Texas
First Name
Britt
Truck Year
1980
Truck Model
GMC K1500 Suburban
Engine Size
350
If the PCB is torn this probably won't work. If not, it might.


I did not know they made this stuff and did solder some stranded wire ( what I had) to repair mine.

I would agree the OE is thicker and better made.
 

Attachments

  • 20220325_192056.jpg
    20220325_192056.jpg
    100.5 KB · Views: 52

GTX63

Full Access Member
Joined
Nov 27, 2022
Posts
933
Reaction score
3,791
Location
Tennessee
First Name
Ty
Truck Year
1985
Truck Model
K10
Engine Size
350
I bought one of those circuit boards from LMC and was very disappointed in the quality. Typical Chinese junk. After I installed it 1/2 the lights didn't work. Found nothing was really wrong with my old one so I just cleaned it up and reinstalled.
I'd do whatever it took to get your original board working.

I have access to enough donor vehicles that I can still go with used OE as a first choice. If I lived more urban or didn't have room for cadaver trucks, I'd use places like LMC or fill in the blank often, and yes, sometimes with a grain of salt. We used to joke in the old days about trucks built on a Monday vs Friday. The modern aftermarket supplier has a quality on par with Walmart. I have aftermarket electronic parts that has lasted for years and other stuff not so much. That is now the state of most consumables.
 

greyghost

Full Access Member
Joined
Jun 15, 2022
Posts
50
Reaction score
15
Location
kansas
First Name
vic
Truck Year
1981
Truck Model
C10
Engine Size
250
aluminum duct tape hvac guys know...somebody makes repair kit for rear window defroster grid that i think is a conductive paint fixes broken grid lines ingenious product
 

bucket

Super Moderator
Staff member
Super Moderator
Joined
Aug 3, 2010
Posts
30,446
Reaction score
28,348
Location
Usually not in Ohio
First Name
Andy
Truck Year
'77, '78, '79, '84, '88
Truck Model
K5 thru K30
Engine Size
350-454
aluminum duct tape hvac guys know...somebody makes repair kit for rear window defroster grid that i think is a conductive paint fixes broken grid lines ingenious product

I believe it might be Permatex that offers the defroster repair kit.
 

Forum statistics

Threads
44,169
Posts
950,808
Members
36,286
Latest member
goodwrenchca
Top