Schematic, TACHOMETER pcb

[Sully69]

Question for Gary Lewis:
I was searching this morning (Google internet search) & found an old thread on FTE about some tach problems. While reading I discovered that a user had sent you a con schematic for a tach. As I am unable to decipher it (too blurry) on my phone, I'm wondering if you still have a copy I can get or that you can post for me. I have an EVTM for my '80 f150 but it doesn't have that schematic. I have a diode on my con that broke somehow. JY near me have some trucks but they tell none have tach's.

Sully

[1986F150Six]

You might also want to get in touch with Ford F834 [Jonathan]. He has experience with the inner workings of the tachometers.

[Gary Lewis]

I'm not finding a tach schematic in my files.  But, is it the tach itself or the connection you are needing?

Perhaps if you gave me a link to the post on FTE it would jog my memory?

[Sully69]

Gary it is the schematic for the pcb. Since nobody local (JY) has any trucks with tachometers I thought I'd buy all new components and fix the one I have

It's an old thread from 2014, I took a shot in the dark, hoping you might still have it.
It was sent to you from "eddiec1564"
The link is below "Factory tach from hell" Post "33 or 34" I believe.

https://www.ford-trucks.com/forums/1341172-factory-tach-from-hell.html?highlight=Factory+tach+hell

Sully

[Steve83]

What do you mean by "con"?  Haynes has a few film circuit layouts, but there are at least 2 for most years.  I have some pics of clusters I've collected over the years, but I doubt I have an '80.

Why don't you post several pics of your cluster, and its film circuit, and any problems you see on it?  We might be able to help you solve them.

[Gary Lewis]

I think he means the tach's printed circuit board, and he's wanting the schematic.  I haven't found it, yet, but I have enlarged the one from the FTE post.  Let's see what this looks like.  And, I added it to the page on Electrical/Tachometers where it is bigger.

Will those work?

[Sully69]

Steve83
"con" seems to be what my phone thinks I want to say when I type in "pcb". Sorry, thought I caught them all but guess I didn't.

Sully

[Sully69]

Gary
That's exactly what I needed, I didn't dl it because I thought it was blurry from.....
I don't know why, just thought an original would be clearer. Thanks, I spent 1/2 the day yesterday in the attic going through boxes looking for wiring diagrams etc.

Thanks again
Sully

[Gary Lewis]

Glad it helped.  Please let us know how the repair goes.  You might have a new profession.  

[Sully69]

Gary,
Back in olden times, after I left the military, I went to school to learn a "trade to fall back on" (as my dad said). I spent 2 years learning electronic technology which, in the '70s, was mostly vacuum tube technology although there were transistors involved. I also went to college & got a Bachelor of Fine Arts degree (music major), all while working days as a mechanic. When rumors of home computers started. I had to go back to learn about them.
I actually learned about 'puters before joining military by hanging out in the basement of MIT learning code from some real strange characters, most looked like they hadn't seen sunlight in years.
A hobby of mine is picking up old receivers, amps, speakers and such things and upgrading the components to today's standards. Love the sound of amps etc from the '60s & '70s.
Sorry about the long winded post lol.
Thanks again, you seem to be a massive wealth of information!

Sully

[Gary Lewis]

I can understand that background.  In the early 60's I got in to amateur radio, and things were all tube then.  (I remember well the 5 tube superhet circuit with the 35W4 and 50C5 tubes.)  Then in the mid-60's I went to college and learned to program on IBM mainframes.  In the early 70's the company I was working for bought a supervisory control & data acquisition system (SCADA) with a PDP-8 computer running it, and I wound up in charge of it - to the point that I troubleshot it to the chip and replaced the chips - which were RTL and TTL.  Then I got into building computers using Intel chip sets, like the 8085 and its peripherals, and even wrote my own operating system for the computer.

So electronics and I are old friends.  I have a scope and a lab power supply, but no longer have the logic tester I once had, which would have made testing the tach easier.

Anyway, if I remember correctly there are tach chips out there.  Might one of those be used to easily repair one of the Bullnose tachs?

[Sully69]

After looking at the clearer schematic, I pretty much decided it would be easier to do just that, build my own board or faster....find one on fleaBay. I dont like getting electronic pieces from there but if its broke, i hope it's an easy fix. I found one there that has ic control although I can't see but a piece of the chip. It's the one without the big cover on the back. My time is worth more than the $50 the seller wants.
Thanks for the help and the info gentlemen.
Sully

[85lebaront2]

Sully, back in olden times (late 50s-early 60s) my dad, an electrical engineer (BS from Severn River Tech, MS from MIT circa 1947) was teaching me about electronics. I used to be quite familiar with the RCA receiving tube guide and dad oversaw me build my own Archer receiver and amplifier. Stereo was just getting really big then, probably 1962, Multiplex was just starting out and dad replaced his Radio Craftsman HiFi system he had built into a cabinet with a nice record changer (33 and 78 only). Thing had a electromagnetic woofer and I don't really remember much on the tweeter other than it looked like a miniature bullhorn. He went to Sears and bought one of their integrated units, stereo with record changer in a nice blond cabinet. There was one of our FM stations that would give a false multiplex signal due to the frequency, Sears finally added a stereo on/off to the balance control.

When I was building my system, dad told me to start with the best turntable, then a good amplifier and finally the speakers. His advice was that a noisy turntable would just be amplified and reproduced through top line speakers, where a fair set of speakers could still sound very nice if not overdriven. I still have the LAB 80 I bought then, a later Dual 1019 and my late wife had a Benjamin Miracord 50H, which I also still have.

To show you what a nerd I am, several friends and I won first place, Group Senior Physics at the 1963 District Science Fair in Norfolk VA for "Construction of a Cyclotron" NASA Langley helped us with the high vacuum equipment, and WNOR 1230 AM donated an old transmitter tube for the oscillator. VEPCO ran us in a 3 phase 440 VAC service to power our motor/generator to give us the high voltage DC we needed. We had a bank of 5 or 6 GE Pyranol? capacitors in parallel. Discharging them was fun, a broom handle with two big nails and a load of copper wire wrapped around them, damn arc would jump to the second nail at about 1" away with a very load bang.

[Ford F834]

I have many tachometers from the junkyard. The general problem with the early, non-integral-circuit type (with the closed back) is that the needle works get sticky, particularly when cold. I have not found a solution to this. Anything I have applied to the needle shaft makes it worse, or does nothing. I have some sticky/non-operative tachs that I could send you as PCB donors.

I am also going to attempt to repair to very rare 80/81 4,000rpm medium duty tachometers with sticky needles by switching the PCB on a properly functioning 6,000 rpm tach. This will leave a couple PCB’s left over if you want to mess with them. I also have some working, integral circuit (open back) tachometer units if the goal is just to get a working OEM tach.

[Steve83]

Sully69 wrote

...I type in "pcb".

It's certainly a printed circuit, but since it's not on a board, I refer to them as "film circuits".

Sully69 wrote

A hobby of mine is picking up old receivers, amps, speakers and such things and upgrading the components to today's standards.

Ooooooohh...

I've been looking for someone to help me (i.e.: do all the hard electronic-design work ) build a few electronic projects.  One is just a couple of pots immersed in silicone oil, but IDK how to shop for them to get the right range/angle/torque for the application.  The idea is a remote oil-damped pendulum (instead of a float) to drive a common fuel gauge.  The other (much harder) is converting a nice Kenwood linear turntable with rare random-access to USB/PC control & output, to make ripping LPs easier.  I have several turntables, and the original repair/service manual with all the diagnostics, but I don't have the skill to read & understand it, or to build a USB interface, or to write the driver.

Gary Lewis wrote

...there are tach chips out there.  Might one of those be used to easily repair one of the Bullnose tachs?

I had planned to just swap the guts of an '87-96 tach onto the back of the '80-86 face.  But then I just swapped bodies, and it became moot for me.

[Gsmblue]

I broke down and bought a tach on eBay. This means the one I have that doesn’t seem to work unless it is 100F outside will be looking for a new home. If anyone wants it I am happy to send it to you free of charge.

Looks like I will be swapping them out next weekend...

[1986F150Six]

 I remembered this had been addressed previously.
 
Selected post  Aug 02, 2018; 2:02pm  Tachometer update [new internals for enclosed type] - not inexpensive, but available.  


1986F150Sixonline

742 posts
 
https://www.rccinnovations.com/index.php?show=menu-tach-all

Scroll down to the 19th tachometer.  

[Rembrant]

That same guys does the 80-86 Ammeter to Voltmeter conversions. I plan to send him my spare this winter to have it done.

https://www.rccinnovations.com/index.php?show=menu-trucks-all

I was looking at a spare cluster at the junkyard the other day (with gauges, but without tach) and I was going to grab it, but I already have a spare cluster so didn't bother. However, I did grab the lens which was decent, and the little manual trans filler plate (in case anybody is ever looking for one).

[Gary Lewis]

I'm glad you grabbed the manual filler as those getting hard to find.  Does it say "Unleaded Fuel Only"?  I know of someone who might be able to use one that doesn't as his dashboard seems to be doing its best to send him that message.  

[Rembrant]

Gary Lewis wrote

I'm glad you grabbed the manual filler as those getting hard to find.  Does it say "Unleaded Fuel Only"?  I know of someone who might be able to use one that doesn't as his dashboard seems to be doing its best to send him that message.  

Gary, no there is no text on the filler plates. My truck has the "Unleaded Fuel Only" text, but it's on the main cluster black fascia panel (I think). I have a US cluster here that does not have the "Unleaded Fuel Only" text on it.

Did some of them say Unleaded Fuel Only on the little filler plates? I'd send somebody one if they needed it...that's why I grabbed it.