I installed a AM converted to newer electronics radio in my 68 bee. The radio was done by instrument specialties and is supposed to have modern electronics, Am/FM and MP3 ports in the back. I removed a working factory AM radio that I had no issues with playing outside the fact of lack of good AM stations, I could listen with no trouble on long trips. With all of that said the new radio is installed and I am having an issue with after about 30 minutes of cruising around it makes a pop that you can hear through the speakers that basically seems to let the radio cut off and right back on. That allows the radio to switch from FM back to AM. it will also make the pop with the MP3 player plugged in, but since the MP3 overrides the radio feature it only pops and goes back to playing. My only thought is maybe after cruising the voltage regulator / alternator let the voltage drop to an amount that might effect the radios electronics? I contacted Instrument Specialties and they asked me to let in play in the car, as they would only be able to bench test it so I let it play in the car not running with a battery charger on to keep the battery from dying and it played with no issues for about an hour and a half. So it is something that happens while it is being driven. I have tried to shake all connections it makes no difference have even rechecked them to make sure they are tight. They are just the factory connections to power the radio and the speakers. I had thoughts of adding the blue mopar performance voltage regulator that provides 14 volts at all times , but don't want to cook my battery on long trips. The regulator that is on the car is a newer electronic style that looks like the 68-69 style. I will say that when first running the car the amp gauge does show positive amps when you first start driving more so than after you have been on the road for a while. It never goes into the negative and I don't have any issue with dead or low battery issues.
Anyone got any thoughts?

Contact member Bigmoney lewis here.he does radios.Probally can answer your questions.Rocky

I would temporarily get a second 12 volt battery of any size, even a gell cell out of a UPS or 12 volt power tool pack, and use this second battery to power the new radio with the intermittent “pop” problem.

This isolates the new radio from the old car electrical system and helps you narrow down whether the problem is in the new radio wiring or elsewhere.

I would run the new radio with the second battery at rest first to see if with nearly no vibration the problem still occurs. Then recharge the second battery and go for ride over increasingly rough roads.

I am going to say you have a capacitor or diode breaking down and momentarily shorting. The question is where???

Factory stock or upgraded charging and ignition systems ?

The charging system is factory alternator that was tested before installing, was a reman unit when purchased so had local parts store check it before installation a couple years back. the ignition system is all Rev-N-ator box, coil, ready to run firecore distributor and firecore plug wires wires.
Matt

It sure sounds like your power going in is getting interrupted while driving ,but not while sitting still. An issue like that is almost never in the radio itself .
It sounds like you have already traced your 12v power red wire going in to the radio and inspected it all the way for any signs of corroded terminals, splices or loose connections all the
way up to the fuseblock on the firewall . We do the exact same FM conversions here at Wards Classic Car Radio Repair , probably 500-600 conversions over the years , and
have had one or two customers who had underdash wiring issues that created such a problem as you described.

Greg

• Go into the glove box and remove the cover to the fuse block
• Disconnect the battery
• Remove the single screw holding in the fuse block
• Easily pull out the fuse block toward U
• Flip the the fuse block over
• Make sure all of the 0.25" tab connectors are tight for each terminal especially the radio terminal, here U might have to slightly squeeze connectors for a snug fit
• Now flip the fuse block back over with the fuses pointed up
• Pull out the radio fuse and slightly pinch the terminals together
• Reinstall the radio fuse and fuse block

Just my $0.02...

Ok ran the radio in the car tonight on ACC while not running. Let the radio run for about 40 minutes and had no issues at all. Then went for a short ride with my son, maybe 15-20 minutes without issue. It in the past it seems like it has to run for about 30 minutes to give any trouble in the radio. I will say that once it happens if you continue to let it play it will continue to happen fairly frequent. If you turn the radio off for a while, say 5 minutes it will take some time before it starts to pop again. So I really don’t know am at a loss. It may not be a fair comparison but the old AM radio would play basically none stop with no issue or pop sound.
I do appreciate all the help and advice, but I would just like to pin point this issue if possible just not sure exactly how. The thought about a diode or something shorting sort of makes since but I’m not sure. It just doesn’t seem to make a difference from the road or anything like that nature.
Matt

Now after your extra testing if it were me I would do those things that Sinitro suggests, then do the second battery that I suggested.

If it is not road vibration it could also be hotter conditions either inside the radio or in the car wiring. You could narrow this down by testing in the cool of the night or hottest part of the day, perhaps even run the car heater.

In radio repair at the circuit board level it is very common to either
heat (small nozzle on an adjustable heat gun)
or cool individual components ( freeze spray can)
to find annoying intermittent faults.

Some multimeters like the Fluke 87 have max/min recording so that you could connect such a meter to your 12 volt supply lines and see if the car wiring momentarily drops to a low level.

Good Luck.

I had the opportunity to drive the car for an extended amount of time this weekend. When you first start to drive the car it takes about 30 minutes of driving and playing the radio to make it pop through the speakers, and that changes it from FM back top AM. If you let it play from there without turning it off it will continue to pop more frequent the longer it continues to play. If you turn the radio off for say 10 minutes and then back on it will play for about 20 minutes without popping again. so I am not sure what really to say beside if it plays continually it will start to pop frequently, if turned off and back on it seem that it does not. I also changed my voltage regulator out on the firewall to make sure that might not have something to do with the trouble , but it changed nothing.
Does anyone know if the voltage limiter on the gauge cluster has any effect on the radio? I know I get a decent amount up and down on my fuel gauge unless I run the headlamps so I am thinking that might be the voltage limiter on the back of the cluster.
Thanks for the reply's and help. Matt

Voltage limiter has nothing to do with the radio. As to fuel gauge operating differently with the lights on I would make sure the dash is well grounded. All the voltage limiter does is turn 12v into 5v(+/-) so you don't fry the gauges.

I think the best way to test was as stated. Run a separate power source and then drive the car.

Sounds like something is heating up and starting to fail in the radio.

Back inteh day I'd open it up and hit things with freeze spray to see if it stopped then replace the part that did.

X2.

With these new conversion boards , the manufacturers recommend using 4 ohm speakers , instead of the factory original 8 ohms .
Although I do run 4 big 8 ohm house speakers for extended periods of time when doing the bench tests before sending back to the customer,
and I have never had an overheating problem with the AAR boards . The same may not be true wit the Aroura boards I don't know .
Also the amount of vol will of course increase the amount of heat over time.
I would look at the impedance of your speakers next , and see what you have.

Greg