I was having problems with our hi-fidelity 6v radio in our 52 F1 build. It would work fine in the garage, but volume would cut in and out on the road under power.

I put a meter on the radio wire and was getting a little over 7.5 volts with engine rpm up. That seemed a little high and that spike seemed to cause the radio issue. I swapped out the regulator to another one and was getting around 7.3 volts with engine rpm up and the radio worked fine.

makes me think the voltage cut out on the first regulator either needs the contacts cleaned or adjusted. Anyone performed a regulator adjustment, how did you do it?

both regulators were NOS still in the box.

JB

 

It is very tricky to adjust generator voltage regulators. They should be pre-set very very close from the factory, even after all these years. 7.3 to 7.5 volts shouldn't make any difference to a radio. It should work over a very wide range of voltages.

A more likely defect today in my opinion would be excessive resistance in the grounds and connections of the truck itself. Make the effort to have absolutely clean and solid grounds and fresh cables of sufficient size. The generator itself must be grounded well to the block, theough the brackets and connecting hardware. Charging systems do not like any resistance at all in the circuit, it will cripple current flow. The regulator itself should have a solid ground reference as well. Ford eventually included a dedicated ground wire from the "G" terminal of the generator to the regulator baseplate for this reason. Could try some troubleshooting with a set of jumper cables, from battery post ground to different components and see if charge voltage changes.

Be really careful trying to clean voltage regulator contacts or make adjustments. Emery paper or sandpaper will get you going again, when stuck on the side of the road, but the comtacts move dozens of times a second with a "wiping" action, they have to be dressed with a spoon file carefully or they will stick, or burn. A straight point file won't ordinarily work. I use a crisp clean new dollar bill soaked in lighter fluid and drag it through the closed points to clean them once in a while. US currency is made of linen, and just abrasive enough.

If you insist on making adjustments use the procedures outlined in the shop manual. They are VERY touchy, and they should be brought down below the target voltage and then brought back up, sort of like tuning a guitar string, if that makes sense. The correct set point is also temperature compensated or corrected for, it might be quite a bit higher than ordinarily supposed. The manual will have the chart, It is a choppy DC waveform. Also use an analog type voltmeter, a modern digital unit either won't work at all depending on what and where you're measuring, or when it does work it probably reads too high leading to misadjustment and a low charge rate.

 

Thanks bud. The restorer put an fm/audio-in board in the radio and upgraded a few components. Maybe some of that stuff is more voltage sensitive.

right on with the grounds, we are still chasing down those issues. Lots of layers of primer and paint to contend with.

thanks for the advice

JB

 

But don't you have taking sandpaper and steel wool to freshly painted metal to get a good ground!

 

Electronics, from vacuum tube to solid state shouldn't be affected by a couple tenths of a volt. Maybe. The first question would be, does the device work at all on battery power? That's going to be considerably less than the charging system voltage.

 

If the radio is cutting in and out while driving down the road, you might also check the antenna connection particularly the antenna ground. Believe it or not the body sheet metal is part of your radios antenna system. Use an ohmmeter and check for continuity between the outside of you antenna connector while its disconnected from your radio. Have someone shake your antenna around a little bit. If the resistance changes, you might need to remove the antenna and clean up the surfaces the antenna grounds to. Also add a ground from the cab to the frame if you don't already have one.

 

If the radio cuts in and out I’d suspect a bad connection, not incorrect voltage. If the antenna cuts out, you’d get static. I’d say you have bad power connection that cuts out with vibration.

If the you had an over voltage condition happening, I’d expect a solid state radio to have a thermal shutdown, which would take a minute or 2 to reset. A tube type radio wouldn’t care at all. I work with tube guitar amplifiers all the time, they run just fine on a wide voltage swing. The tone and clarity changes, but they don’t cut out, even with voltages well below or above spec.

 

As I recall, you used old NOS condensers for static suppression on the gauges? Capacitors don't age well, and become susceptible to moisture intrusion. I'd remove them and see if it makes a difference.

 

typcailly an electrolytic cap will start deteriorating after 20 years or so, but the typical film or ceramic caps used in noise suppression can last almost forever. That said, anything is possible.

 

This is true but I bet they didn't use film caps for noise suppression. Paper/foil or something like that.

 

Thanks guys, it’s working great now so if it’s not broken don’t fix it. Will continue to watch it. The restorer was concerned the vibrator is pulling too much current.

JB

 

I’d think either ceramic or wax paper and foil. I’ve seen wax paper and foil caps run for 50 years, shift a bit in value but not short or open like an electrolytic cap. My 50s Hammond Organ has a few hundred of them still functing.

But it sound@3twinridges has the problem licked, that’s great.

 

If they are constructed anything like the ignition condensers, they are definitely suspect. They sure look very similar, a metal cased unit, only the capacitance or voltage is different. I have a bunch of NOS ignition condensers and they mostly fail the high voltage test. I've noticed the noise suppression caps are expensive for what they are, and kind of hard to find.