Cvr Replaced With 7805 Or 7806 Chip

This thread kinda went off track, discussing this topic.
Another Horn Question-74 Cj5

Lots of links to parts and stuff in that other thread.

I looked in my junk pile and found I had the parts to do this on hand.



The wire was scavenged from a dead computer power supply. IThe 7805 came from a temporary +/- 5V supply that was built on a scrap of vector board. It's a Motorola 78T05A, 1A fixed 5V regulator, TO-220 package. Not sure what the capacitor attached to the lugcame from - it's a 470nF film type, probably polyester with a 50V rating? The other capacitor is a similar film type at 150nF and 50V? I can easily measure the capacitance, but the voltage rating is a mystery. These brown Panasonic caps are NLA. Suitable.

Since this package is grounded through the tab, I clipped off the ground lead and straightened the other two leads (input and output). I then wrapped one lead of the capacitors around the remaining 7805 leads (470nF on input, 150nF on output) and positioned the parts for soldering.


Notice that I'm letting gravity help me here, with the soldered joint up where I can reach it and the parts dangling down where they will want to. This leaves one hand free to hold the soldering iron and the other holds the solder. The lug will be used on the tab to secure the other ends of the capacitors to ground.


Soldered to the IC, and ready to be attached to the lug. Sorry about the focus here - the camera should be able to focus that close, but something in the auto-focus picks objects in the background.


I put the wires through the bent lug now under the screw and soldered. Another of this type of lug is on the bench.



The wires and IC leads are tinned and the wire set on top, to be soldered with my third hand (I can't snap the pic, hold the wire and solder at the same time). All I did was hold the wire on the IC lead and touch the iron to it to make the joint. No need to try and wrap the wire around or such.


Some heat shrink around the joints completes the job. This is the same adhesive-lined heat shrink from 3M that I use to make splices in automobiles. It stiffens the connection between the wire and the IC considerable, and reduces the chance that vibration or other stress on the wires will break off the leads at the IC. You should still anchor the wires close to the IC, to prevent them flopping around.



Here's a picture of this lashup from another angle. I placed the heat sink compound in the foreground and now focus is good... Suggest you use a bit of this type of compound under the IC when it's mounted to the cluster or body steel.Note this says silicone, but it's not silicone grease. It contains some white mineral stuff (zinc oxide I believe) that makes a good heat-conductive bond between the IC and the mounting surface.I bought this tube at a hamfest 20 years ago (?) and there is plenty remaining.

All that remains is disconnect the existing CVR from 12V and connect the black wire to 12V, the yellow wire to the 5V output of the CVR, and mount the IC on steel somewhere that is a good ground.

 

After studying the camera manual, I took these:





I figured I better test it.



4.93 volts is ok. 1.4% voltage error. This is 12 volts in with a 100mA (50 ohms) load.

Same 4.93V with a 25 ohm load; could not run it long since the chip gets increasingly warm. Also same with different meters.

 

OK so this is to replace a burned out CVR in the fuel gauge
I see what you did , still the electrical parts used . is out of my range of thought

 

Thanks Timgr,...... I do admire your technical genius. Then , Ron's thought X 100, here.

 

I sincerely believe that this thread will be archived & used by others , to help them in their repairs.

Tim , please do not take this post as disrespect , but a layman such as I checked on some terminology definitions & I found my first search Hysterical !
......Particularly line # 9 * This abbreviation was familiar , 'Cuz I use # 4 in my Trade *

Forgive Me, please.

CVR


Acronym Definition
CVR Cover
CVR Cover (postal stationery)
CVR Cockpit Voice Recorder
CVR Concealed Vertical Rod
CVR Combat Vehicle Recconaissance (armored fighting vehicles; various locations)
CVR Change Verification Record
CVR Configuration Verification Review
CVR Circuit Validation Response
CVR Contraceptive Vaginal Ring (drug delivery device)
CVR CPAM (Congenital Pulmonary Airway Malformation) Volume Ratio (cardiology)
CVR Computerized Vehicle Registration
CVR Conversion Rate
CVR Cultivar
CVR Contingent Value Right (stock)
CVR Centre for Vision Research (York University, Toronto, Ontario, Canada)
CVR Certified Verbatim Reporter
CVR Central Valley Reefers
CVR Communauté de Communes du Vendômois Rural (French: Community of Municipalities of Rural Vendôme; Vendôme, France)
CVR Central Business Register (Denmark)
CVR Conservation Voltage Reduction (power industry)
CVR Circuits Voyages Renaux (French travel agency)
CVR Cardiac Valve Regurgitation
CVR Claye Véhicule Rétro (French automobile club)
CVR Cardiovascular Recovery
CVR Cost Value Reconciliation
CVR Compagnie Vinicole des Rivesaltes (French winery)
CVR Continuously Variable Regulator
CVR Controlled Ventricular Response
CVR Cell Delay Variation
CVR Conservation Voltage Regulation (energy conservation)
CVR Content Validity Ratio (Statistical analysis)
CVR Code de la Voirie Routière (French: Code of Road Traffic)
CVR Chemical Vapor Reaction
CVR Center Vertical Restraint
CVR Contributor Value Rating (sports statistic)
CVR Current Viewing Resistor
CVR Crystal Video Receiver
CVR Centralized Voter Registration
CVR Chapter-Verse Reference
CVR Change Verification Record (NASA)
CVR Computer Voice Response
CVR Classified Visit Request
CVR Converted Rights
CVR Centrale Virksomheds Registrering (number)
CVR Cost, Value and Risk
CVR Cost Variance Report
CVR Credential Verification Review (New York State Office of the Medicaid Inspector General)

 

It's in the thread I linked at the top. Or in the TSM.

 

Tim an I have been involved in a very lengthy discussion on this subject in this thread linked below.
There is discussion on what parts and where to get them and how to install them. Tims outline above is very spot on as to the assembly of the new parts needed and how to assemble the new Constant Voltage Regulator. The 7805 5 Volt chip will work just as well as a 7806 6Volt chip. ( The original CVR in the fuel gauge produced 5 Volts) But the gauges should perform without any ill effects from a 6 Volt 7806 chip. Jim
Another Horn Question-74 Cj5