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runamoc Samba Member
Joined: June 19, 2006 Posts: 5601 Location: 37.5N 77.1W
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Posted: Sat Jun 09, 2018 2:20 pm Post subject: Re: Request for tach hookup clarification |
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FL-Frank wrote: |
“A picture is worth a thousand words”.....
Is this diagram correct for wiring the tach with a diode, the “doubler”, an IC voltage regulator, and a capacitor?
If not, what corrections are needed?
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The schematic for the chip shows a capacitor on both the input and output to ground. So, I not sure. The site you link will work but this looks like a better deal.
https://www.ebay.com/itm/E-Projects-10uF-50V-105c-...xypNtSlP60 _________________ Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Sun Jun 10, 2018 9:02 am Post subject: Re: Request for tach hookup clarification |
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Second capacitor added to the diagram.
Whats the best way to connect the positive leads of the capacitors to the wires which continue on to the regulator and the doubler?
Also, in order to avoid drilling additional holes in the chassis for ground connections, can I use the same existing hole to connect all 4 ground leads?
_________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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runamoc Samba Member
Joined: June 19, 2006 Posts: 5601 Location: 37.5N 77.1W
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Posted: Sun Jun 10, 2018 10:48 am Post subject: Re: Request for tach hookup clarification |
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Quote: |
Whats the best way to connect the positive leads of the capacitors to the wires which continue on to the regulator and the doubler?
Also, in order to avoid drilling additional holes in the chassis for ground connections, can I use the same existing hole to connect all 4 ground leads? |
Put the capacitor leads with one of the wire ends into the butt connection and crimp.
Not sure of your year Ghia but my '72 has this ground array on the driver side hood spring support 'thing'. Maybe you have some open spots.
_________________ Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Sun Jun 10, 2018 2:24 pm Post subject: Re: Request for tach hookup clarification |
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Thanks, it’s a 1964 and has only one factory hole on the driver’s side hood spring bracket (or whatever its called). Like I said, I really don’t want to drill more holes...will stacking the 4 ground connections at this location suffice?
_________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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runamoc Samba Member
Joined: June 19, 2006 Posts: 5601 Location: 37.5N 77.1W
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Posted: Sun Jun 10, 2018 6:52 pm Post subject: Re: Request for tach hookup clarification |
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Quote: |
will stacking the 4 ground connections at this location suffice? |
Yes. Not sure if that's a screw or a bolt with a nut. If it is you can put connections on both sides. You can also put some under that nut holding the flasher too.
Yellow crimps can hold two wires. Some on here swear by those thin brass crimp connectors that were OG. I think Thomas&Bates crimp connectors are by far better electrically than that. They are usually not sold in the LAPS though. _________________ Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Mon Jun 11, 2018 9:38 am Post subject: Re: Request for tach hookup clarification |
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runamoc wrote: |
Quote: |
will stacking the 4 ground connections at this location suffice? |
Yes. Not sure if that's a screw or a bolt with a nut. If it is you can put connections on both sides. You can also put some under that nut holding the flasher too. |
Thanks, pictured is a M5 x 0.8mm thread 16mm long pan head machine screw with a flat washer under the head and an external tooth lock washer between the ring connector and the chassis. On the back there’s a split lock washer and nut. So if I size up to a 25mm length screw, it should easily accommodate the 4 stacked connections or 2 on the front and 2 on the back of the bracket. _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Fri Jun 15, 2018 10:39 am Post subject: Re: Request for tach hookup clarification |
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This morning I fabbed a harness to add the inline voltage regulator and the two capacitors, and connected everything as per my previously attached diagram (the one with the two capacitors).
Although I was very hopeful this would resolve the previous issue of the tach reading too high....Now the tach needle doesn’t move at all
With a multimeter and the engine running...
6.21 v at terminal 15 on the back of the ignition switch leading to the VR through the capacitor
0.0 v at the + inbound post on the doubler
0.0 v at the + outbound post on the doubler
0.0 v at the + post on the back of the tach
I know the doubler and the tach were functioning before I wired in the VR and capacitors, so it would appear that this new issue has something to do with the VR and/or capacitors. I’m wondering if the problem is being caused by the way I connected the 3 wires to VR. Since its lead are so close together, crimping isn’t a viable option. So, I used narrow shrink tube to join each of the VR’s three leads to their respective wires, followed by a larger diameter shrink tube encasing the VR and the wire connections. I gave the wires several good tugs, and nothing budged.
Since it looks like I’ll have to dismantle the whole thing and start from scratch, what is the best way to connect the 3 wires to the VR leads? There is only about 1 mm space between the leads, and they’re very rigid. I didn’t want to risk breaking them by attempting to bend them to separate them further. _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD
Last edited by FL-Frank on Fri Jun 15, 2018 11:24 am; edited 1 time in total |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Fri Jun 15, 2018 11:16 am Post subject: Re: Request for tach hookup clarification |
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I just disconnected my VR and capacitor harness, reconnected the tach as I originally had it, and the tach reads again. Too high, but at least its not dead.
Multimeter readings at idle are now....
6.21 v at terminal 15 on back of ign switch
6.21 v into doubler
12.13 v at + terminal on back of tach
Now what? _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Sun Jun 17, 2018 9:43 am Post subject: Re: Request for tach hookup clarification |
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I also read the voltage this morning with lights off and on. Although the voltage at the ignition switch dropped to 5.5 v with the headlamps turned on, the doubler was still delivering 12.13 v to the tach with lights on.
On Friday afternoon, I called and updated the folks at NHS on the situation, and they volunteered to send me a tested and known to read accurate 6 v tach that I can install without the doubler. The thought is with both tachs connected simultaneously, if the second or “control” tach reads accurately, then we’ll know something is amiss with the 12 v tach in the dash. If the control tach also reads high, then the problem lies elsewhere...possibly the Pertronix ignition. If it gets to that point, I’ll probably have to swap in a set of conventional points to see if that corrects the high reading issue. _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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VeloMikey Samba Member
Joined: March 19, 2012 Posts: 655 Location: So Cal
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Posted: Sun Jun 17, 2018 10:10 am Post subject: Re: Request for tach hookup clarification |
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FL-Frank wrote: |
Thanks, it’s a 1964 and has only one factory hole on the driver’s side hood spring bracket (or whatever its called). Like I said, I really don’t want to drill more holes...will stacking the 4 ground connections at this location suffice?
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First, you can ground a million things to that screw. Lets turn it into a ground "lug". Take out the Philips head screw and turn it around so the threads face forward. Put the serrated lock washer and nut on without any wires connected. Now stack all you ground wires on the nut and put anther nut on the treads. You have just created a ground lug and you don't have to fumble with the Philips head anymore. Keep stacking the grounds between the two nuts on the threaded lug. If that screw is not long enough, replace it with a longer screw or bolt. It the hole is threaded, drill it out so you can slip the bolt thru and put a nut on it.
Take the tach to the motor compartment and hook it up with a new clean wires. Colors don't matter. Get three piece 24" long. Hook the + on the tach to the + on the coil. Hook the signal wire up to the - on the coil and hook the ground up to the neg side of the battery if it is in the motor compartment or to a good ground like the generator stand. Start the car, does it read correctly? How about hooking the tach up in a 12v car the same way to see if truly is correct "in the field" not on the bench. _________________ '58 Ghia 2387cc with a Berg / Folts 5 Speed
Ghia Build Thread https://www.thesamba.com/vw/forum/viewtopic.php?t=768748 |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Fri Jun 22, 2018 2:42 pm Post subject: Re: Request for tach hookup clarification |
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The “control” tach from NHS arrived today...they actually sent two, one 6 v to be connected without the doubler, and one 12 v to be connected with the doubler.
I first hooked up the 6 v control tach, and had it in my lap so I could watch it and the original dash mounted tach while I test drove. The control tach worked perfectly....accurate readings throughout the rpm range regardless if lights were switched on or off. The dash mounted tach still read way high and dropped down when lights were turned on.
Next I hooked up the 12 v control tach through the doubler and test drove again. It worked perfectly...accurate readings throughout the rpm range regardless if lights were on or off.
I called NHS with the results, and their conclusion is
There is nothing wrong with my cars wiring
The doubler appears to be working correctly
The original tach they sent me is faulty
So, I’ll send the original one back to them along with the 12 v control tach so they can swap the movement from the control tach to the original tach.
I really hope this is the final resolution to the problem, even though I’m getting pretty good at removing and installing tachs _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Fri Jul 06, 2018 11:59 am Post subject: Re: Request for tach hookup clarification |
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The latest edition of the tach from NHS arrived today. 5 minutes to install it and connect the wires....and...finally...it works correctly!
This project certainly tested my patience, but it was worth it in the end!
_________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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c21darrel Samba Member
Joined: January 22, 2009 Posts: 8211 Location: San Dimas
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runamoc Samba Member
Joined: June 19, 2006 Posts: 5601 Location: 37.5N 77.1W
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Posted: Fri Jul 06, 2018 2:41 pm Post subject: Re: Request for tach hookup clarification |
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_________________ Daily driver: '69 Baja owned 44 yrs - Plan B: '81 Rabbit Diesel LS Deluxe - Plan C: '72 Ghia
Yard Art: 2 Sandrails
Outback: '69 Ghia - '68,'69,'70,'72 Beetle - '84 Scirocco, GTI - Pair of '02 Golfs-
VW Wiring = It's just wires |
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FL-Frank Samba Member
Joined: August 08, 2015 Posts: 823 Location: Jupiter, Florida
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Posted: Mon Sep 24, 2018 11:32 am Post subject: Re: Request for tach hookup clarification |
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Update....
A couple of weeks ago, the tach mysteriously stopped working. After checking all connections, I reported the problem to NHS and they asked me to send it back to them for diagnosis. The following week they contacted me to say the board was toast, and that they were sending me a replacement tach.
The replacement arrived and When I installed it, same issues as I originally had with inaccurate readings. NHS worked with me on the phone to try to adjust the tach to read correctly, however, we could only get it fairly close and the needle fluttered quite a bit.
Meanwhile, I saw a link to Pertronix Tech Support Bulletin on another post that recommends using an inline resistor rather than the inline diode.
http://support.pertronix.com/kb/faq.php?id=34
I replaced the diode with the resistor today, and voila! The tach now reads accurately at idle and up and down the rpm range. The needle no longer flutters, and the sweep is silky smooth. _________________ “Tinker Toy” 1967 Savannah Beige Beetle Sedan...........Mostly Original Survivor
“Fritz” 1964 Gulf Blue Karmann Ghia Coupe...Complete Pan-Off Restoration SOLD |
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Sofia74 Samba Member
Joined: August 30, 2015 Posts: 565 Location: WV
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Posted: Sun Nov 01, 2020 2:44 pm Post subject: Re: Request for tach hookup clarification |
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This post has been very helpful but I have a NHS specific question. I haven't heard back from them yet so I thought I'd throw it out here.
My tach has three tabs - labeled green, black and red. And I know I need power, coil and ground.
Am I right in thinking:
green - coil
black - power
red - ground
I see online that it looks like different companies use different color coding.
Wondering if anyone has any experience with NHS color coding. Still bugging them as well... |
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VeloMikey Samba Member
Joined: March 19, 2012 Posts: 655 Location: So Cal
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Posted: Sun Nov 01, 2020 4:11 pm Post subject: Re: Request for tach hookup clarification |
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Red is positive or hot
Black is ground
Green is negative side of the coil _________________ '58 Ghia 2387cc with a Berg / Folts 5 Speed
Ghia Build Thread https://www.thesamba.com/vw/forum/viewtopic.php?t=768748 |
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Sofia74 Samba Member
Joined: August 30, 2015 Posts: 565 Location: WV
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Posted: Tue Nov 03, 2020 3:31 pm Post subject: Re: Request for tach hookup clarification |
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Thanks. Sure wish I understood why red is power sometimes and black is power sometimes and maybe they could have used brown for ground...?
But thanks. Exactly what I needed. |
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VeloMikey Samba Member
Joined: March 19, 2012 Posts: 655 Location: So Cal
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Posted: Tue Nov 03, 2020 5:51 pm Post subject: Re: Request for tach hookup clarification |
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Sofia74 wrote: |
Thanks. Sure wish I understood why red is power sometimes and black is power sometimes and maybe they could have used brown for ground...?
But thanks. Exactly what I needed. |
VW used red for constant hots like horns, dome lights and clocks and black for switched hots like the coil.VW used brown for earth or grounds.
You can wire your tach up with a black to the Pos(+) from the ignition switch, a brown to the ground and a green to the negative side of the coil.
VW used grey with a red stripe for the dash light.
Today's standard for tachs is red is hot, black ground, green coil and white for the lights. That is pretty much it for all gauges. The sender wire is your color choice. _________________ '58 Ghia 2387cc with a Berg / Folts 5 Speed
Ghia Build Thread https://www.thesamba.com/vw/forum/viewtopic.php?t=768748 |
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