Tachometer Circut Boards
Thread Starter
Cruising
Joined: Oct 2005
Posts: 12
Likes: 0
From: New Holland, PA - U.S.A.
Tachometer Circut Boards
I earlier submitted a question on my tach issue, and the conclusion was that I needed a new circut board. Thanks for the Help.
Many have said to buy a good board and watch where you get it from. One individual even bought from a big Corvette Parts supplier and the board was bad. Where is a good place to get a circut board? I found this on E-Bay and was wondering if any one has purchased from him and would recommend. (I have a 1975 Corvette)
Tach Circut Board
Many have said to buy a good board and watch where you get it from. One individual even bought from a big Corvette Parts supplier and the board was bad. Where is a good place to get a circut board? I found this on E-Bay and was wondering if any one has purchased from him and would recommend. (I have a 1975 Corvette)
Tach Circut Board
Racer
Joined: Jul 2005
Posts: 499
Likes: 1
From: Winnipeg Manitoba
This name has come up before, but I can't seem to find it by searching.
I don't recall if the feedback was good or bad.
1) It looks like he's using the standard tach chip and recommended circuit.
(National LM1819 or equivelant)
If he's got the std chip and is following the data sheet,
then the worst he can do is solder joints.
2) Ask him if he copied the 75/76 circuit directly, or if he corrected the design problem that leads to the burnt spot.
(75/76 used a zener to protect against overvoltage,
problem is reverse battery will immediately burn out a trace!)
3) His troubleshooting information appears to be correct and from it,
I would say he knows what he's talking about.
4) If your board is an original 75/76 with a burnt trace, it might be repairable. Jumper the trace and replace the zener diode on the input.
EDIT: Out of curiosity, I asked Gardner my questions about his boards.
1) He uses the std chip.
2) He's updated the 75/76 boards to eliminate the common problem of the burnt trace.
I don't recall if the feedback was good or bad.
1) It looks like he's using the standard tach chip and recommended circuit.
(National LM1819 or equivelant)
If he's got the std chip and is following the data sheet,
then the worst he can do is solder joints.
2) Ask him if he copied the 75/76 circuit directly, or if he corrected the design problem that leads to the burnt spot.
(75/76 used a zener to protect against overvoltage,
problem is reverse battery will immediately burn out a trace!)
3) His troubleshooting information appears to be correct and from it,
I would say he knows what he's talking about.
4) If your board is an original 75/76 with a burnt trace, it might be repairable. Jumper the trace and replace the zener diode on the input.
EDIT: Out of curiosity, I asked Gardner my questions about his boards.
1) He uses the std chip.
2) He's updated the 75/76 boards to eliminate the common problem of the burnt trace.
Last edited by Kilroy1024; Jan 10, 2006 at 09:36 AM.
Pro
Joined: Mar 2003
Posts: 553
Likes: 1
From: Valparaiso IN
Originally Posted by Kilroy1024
4) If your board is an original 75/76 with a burnt trace, it might be repairable. Jumper the trace and replace the zener diode on the input.
.
.
Which Zener is the one to replace?
Racer
Joined: Sep 2004
Posts: 482
Likes: 1
From: Brandon Manitoba
I bought a tach board from Ecklers to fix my burnt 80 board. The board from them did not cure my problem. Emailed them 2 times about the situation with no reply. My advise, buy from somewhere other than ecklers. Brent
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Racer
Joined: Jul 2005
Posts: 499
Likes: 1
From: Winnipeg Manitoba
Originally Posted by OldSchool
Which Zener is the one to replace?
A picture of the board pulled out of my 76 can be found here:
http://members.shaw.ca/gvn/1976.html
No gaurantee that the board was the same for the whole year.
The zener is the black round component connected across + and -.
Datasheet specifies 18V/1W 2N2476 or equivelant.
As stated, Mike Mercury often has input to these threads.
He can repair and calibrate your tach if you don't want to tackle it yourself.
Getting the pointer off and cleaning the face can be a bit tricky.
Oh yeah, and I can't say this enough: DO NOT TOUCH THE FACE!
The ink can smear. If you want to clean it, use an air compressor.
Q-Tip smudges on the black areas can be cleaned with a Q-TIP.
Better yet, leave it.
I've been gathering tach info to post on a webpage,
Which I will get around to someday.......
Last edited by Kilroy1024; Jan 10, 2006 at 08:47 PM.
Burning Brakes
Joined: Jul 2003
Posts: 868
Likes: 5
Originally Posted by jdmick
Usually "Mike Mercury" here responds that he fixes them. Might want to PM him.
The Ecklers boards are junk....not only do not work some have a really bad design on the back side that has metal linings for all three holes that the studs stick through...all three metal holes touch the metal coil.Most of you know that you can't have a signal,positive and a ground TOUCHING!.The gardner boards are the best.
BOOMER'S 75 Vette-email me about this I can help
Jason
VetteInstruments@aol.com
