Dino DIY - Voltage Regulator testing / AMMETER flicker | FerrariChat
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Dino DIY - Voltage Regulator testing / AMMETER flicker

Discussion in '206/246' started by synchro, Apr 13, 2008.

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  1. synchro

    synchro F1 Veteran

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    #1 synchro, Apr 13, 2008
    Last edited by a moderator: Sep 7, 2017
    My Ammeter has a twitchy movement to it and flickers quickly in one direction or the other, especially around the zero point. I wasn't sure if this was due to an "electrical event" that I recently had or not but wanted to investigate and I longed to the smooth movement behavior that it should have.

    I telephone our local NWR-FCA club Technical expert, Carlo Durante, at Alfa of Tacoma (our go-to-guy when tough problems arise) and explained my situation. He stated that it may be the gauge or a remote possibility is that the contacts on the Voltage Regulator are pitted. While I can't due much about the gauge, I can easily test the Voltage regulator and clean the contacts.

    My Euro Dino has the black Voltage Regulator mounted on the fuse box/relay panel in the front of the car (USA cars typically have a three wire, red Marelli unit mounted under the dash).

    Pin 15 is from Power switched through the ignition ON and I measured 12.68 Volts so it was OK
    Pin 67 goes to the Alternator field and the wiring shows 0.3 ohms so that line is OK
    Ground is from casing via the black wire and measures 0.2 Ohms to the battery GND connection so is also OK
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  2. synchro

    synchro F1 Veteran

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    #2 synchro, Apr 13, 2008
    Last edited by a moderator: Sep 7, 2017
    Using a flathead screwdriver, remove the Voltage Regulator and unscrew the canister case's two phillips head screws.

    Angelo Wallace's translation of "the Ferrari Dino workshop manual" talks about two transistors and diiodes but they are not in this old style unit.
    The Dino Voltage Regulatort is simply an electromechanical switch. I examined the contacts and there was a very minor black marking on the contact points, not very pitted at all, but could use a little cleaning up
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  3. synchro

    synchro F1 Veteran

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    #3 synchro, Apr 13, 2008
    Last edited by a moderator: Sep 7, 2017
  4. synchro

    synchro F1 Veteran

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    #4 synchro, Apr 13, 2008
    Last edited by a moderator: Sep 7, 2017
    To Test the Voltage Regulator, I'll apply DC voltage and hope to see it switch at around 14.5 to 14.75 Volts. The function of the Voltage regulator is to provide zero volts to the alternator field coil up to this range (14.5 to 14.75 Volts) which causes the alternator to charge the battery, and above that it provides a positive voltage to the field coil which halts the alternator from charging the battery.

    An easy test setup uses standard Batteries, but you must measure the voltage between Pin 15 (Power) and the case (Ground) and observe/listen for when the relay "clicks" indicating the change.
    Mine switched at 14.6 volts which is operating correctly.

    I cleaned up the contacts, reassembled and then reinstalled the unit in the car knowing it was working fine and the car's wiring was good. Unfortunately this means the problem is in the dash mounted Ammeter gauge.

    I then called Joey at Mo-Ma about his Ammeter gauge upgrade and shipped it to him at:
    Mo-Ma
    1321 2nd Street Northwest
    Albuquerque, NM
    87102
    (505) 766-6661

    I'll know more in a bit when he has the unit to work on.
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  5. jselevan

    jselevan Formula 3

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    #5 jselevan, Apr 13, 2008
    Scott - sorry to hear of your twitchy amp meter. However, old-style electromechanical voltage regulators will, by their nature, result in discontinuities (on-off) and "twitchy" amp meters. After all, unlike a modern transistor regulator, the electromechanical regulator is an on-off device. Either it charges the battery (plus amp meter movement) or the battery discharges (negative amp meter movement). There is no gradual "seeking" of a zero current condition. It is referred to as a "Bang-bang" feedback control system.

    My comments may be without merit if your amp meter, heretofore, was as smooth as silk. I would be surprised if that was the case. It is more likely that if you had a smooth amp meter, then something was wrong to lead to a smooth amp meter, rather than the opposite.

    I invite others to discuss this issue. It is interesting, as old-style electromechanical regulators are not seen often. They are most commonly seen today in old Jaguars, the true Vanna Whites of the automotive world...they look great but do nothing. After all, a moving violation in a Jaguar is an oxymoron.

    Jim S.
     
  6. John Corbani

    John Corbani Formula 3
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    #6 John Corbani, Apr 14, 2008
    Scott, Jim,
    I had an electromechanical regulator when I bought car. It died and I replaced it with an electronic unit from Pep Boys. Chrysler had a 3 terminal regulator back a ways. Works fine. It did nothing to remove the "kick" of the ammeter when anything turns on or off. Turn signals, fans, etc., cause the kick as did the regulator. Actually the regulator did not cause much trouble because it switches on and off so fast once revs are up. The speed gives the effect of a smooth action. Basically the problem is an old meter. Once upon a time the meter probably had a heavy oil in the pivots to dampen the pointer swings. Oil may be evaporated by now. Nowadays a special silicone oil is used and it does not evaporate. An instrument service company might be able to add oil if they can get into the movement. If not, just live with the twiches as I have learned to do. Mechanical regulators can be adjusted fairly easily but the best thing to do is just replace them if problems show up. Learned that on English cars a long time ago.
    John
     
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  7. synchro

    synchro F1 Veteran

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    #7 synchro, Apr 14, 2008

    I have two Dinos; Euro and USA (see profile pics) The Euro is the one in this topic with the flickering that I sent in to Mo-Ma for repair (and the USA one never had that flickering movement).

    This last weekend I swapped the USA ammeter into the Euro car aqnd it was quite smooth. Did it just to go on a drive (it was the FIRST day this year that it has been sunny and above 70 degrees.
    Photos from the drive:
    http://www.ferrarichat.com/forum/showpost.php?p=137627859&postcount=963


    Yes, Carlo said the regulator was a low probability as a source of this problem, but hey I'll try anything - plus while I'm there I might as well right an Fchat DIY article to help others out in a similar situation.

    Joey at Mo-Ma said that there are internals in the AMMETER that could be affected after a bad electrical event but I'll find out more when I get it back - ETA is a week or so ...
     
  8. rwk360

    rwk360 Formula Junior

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    #8 rwk360, Apr 15, 2008
    Interesting and to me, timely thread. My L-series had a heretofore smooth operation of the ammeter, and in the last two mos or so has begun this twitching movement, which also appears to be rpm dependent (tends to disappear at higher revs). Since (knock on wood) I've noticed no other electrical symptoms or issues, I surmise that I probably have no problem (?).
     
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  9. John Corbani

    John Corbani Formula 3
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    #9 John Corbani, Apr 15, 2008
    Don't jump to conclusions just yet Robert. My flickering is a resut of something going on or off and the ammeter "bouncing" after the fact. If the ammeter bounces for no reason, the alternator brushes might be going bad or some other malady. It is usually worse at low speeds and cleans up with time or temperature or revs. Dinos know all the ways to have problems. Just pick them off one at a time. I have been.
    John
     
  10. synchro

    synchro F1 Veteran

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    #10 synchro, Apr 15, 2008


    I re-read my rsponse and I may have missed your point - that we should not take the gauge movements too literally and we should not demand high accuracy from these 1970's (1960's ?) instruments. If so, then I truly agree.

    Apologies if I've mis-interpretted your response.

    Sincerely,

    Scott
     
  11. jselevan

    jselevan Formula 3

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    #11 jselevan, Apr 15, 2008
    Scott - no problem. I did not sense anything untoward in your reply. Indeed, the amp meters are good for knowing 1) charging, 2) charging a lot, 3) discharging, 4) discharging alot. That's about it. Not much better than an idiot light.

    Jim S.
     
  12. synchro

    synchro F1 Veteran

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    #12 synchro, Aug 11, 2015
    Bump
     
  13. dino clay

    dino clay Karting

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    #13 dino clay, Aug 13, 2015
    stop!!!! 1st check the connections to the amp gauge!!!!
     
  14. synchro

    synchro F1 Veteran

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    #14 synchro, Jul 24, 2019
    Excellent precaution.
    Also, I bought several of those rubber boots from Superformance intended for the distributor exterior wires and found they fit the two Ammeter rear connections very well. (Distributor Wire Rubber Cap: 212-28919 http://www.superformance.co.uk/246/ignition.html)
    Nice insulation and protection against accidental shorts

    Great research, Thank you

    I see Superformance sell them. The image is small but it looks like the Fiat not the Marelli because it is missing the reinforcing baseplate
    ( Alternator Regulator Black Box Type 24618065 http://www.superformance.co.uk/246/electrical.html )

    AutoRicambi also sellls them for $179 USD
    https://autoricambi.us/products/voltage-regulator-oem-original-external
     
  15. TonyL

    TonyL F1 Rookie

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    #15 TonyL, Jul 24, 2019
    Scott, several years ago I had similar issues with the charging circuit, namely high charging current, overloading of the wiring and massive gauge flicker.

    I did a few things

    1. cleaned the gauge terminals and fitted nyloc nuts.
    2. cleaned the alternator fuses and fuse carrier + terminals
    3. Renewed & Insulated the alternator cable to the fuse box with heat resistant sleeving. (mine had signs of heat damage from the exhaust, brittle cable and high resistance)
    4. Remade all the terminal connections with new spade / ring terminals
    5. cleaned the earth connection to the voltage regulator
    6. ditched the old mechanical VR and fitted the electronic one. Huco 130723 14v [much better than the Sf unit and cheaper]


    With item 6 I removed the old mechanical VR cover, made a small modification by cutting out a small section from the base and refitting over the new electronic unit. You cannot see the mod and so looks original but with the added benefit of modern electronic control.

    No more charging issues & stable ammeter needle, more importantly the wiring stays within limits

    Tony
     
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  16. synchro

    synchro F1 Veteran

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    #16 synchro, Aug 1, 2019
    I was rumaging around in a box of spares from my Italian version Dino and found two of the Voltage Regulators that Rob refer to; the Fiat and the Magnetti Marelli
    Please find photos of top and bottom

    If the MM was a later version then the added base was a change from the original design.
    Note that the MM here also has the large, white "2" painted on the shell as in others' posted photos above.


    If anyone needs one of these PM me as they are in good condition with OEM stickers still intact but I sold that Italian version Dino so can't use them


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  17. HMB-Dino

    HMB-Dino Formula 3
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    #17 HMB-Dino, Aug 1, 2019
    Can't figure out how to PM since the switch to this format. But I'm interested in the FIAT one, so perhaps you can PM me..
     
  18. synchro

    synchro F1 Veteran

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    #18 synchro, Aug 4, 2019
    Have the Marelli left for $50 + s&h
     

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