BigT-65

I am going to try your suggestions
Thanks

BigT-65

I just put my old mechanical VR back in the vette. I think my radio problems started after I changed to the electronic VR which was also not new. I am going to try it out shortly. It's 93 degrees outside and about 75 inside so I am not crazy about going out right now.

Gary's '66

Remember, if you should lose power to the radio turn on other accessories, heater fan (on high) and even headlights at the same time to see if power returns to the radio. Good luck.

Gary

BigT-65

I went out and drove around for about a half hour or so and the radio did not shut off. I actually went out twice once with the radio on and the other time with the USB on. The reason I took that mechanical VR out in the first place was that it stayed at +20 or more the whole time I was driving and the battery was not run down. I guess I will have to go buy a new electronic VR and see what happens with that. After I put the old electronic VR back in I will try it again and if it cuts off. If it does I'll put the headlights on and see what happens. Like a previous post said, these radios are a POS. and they do not have good bass. I wouldn't recommend that anyone buy one of these radios.

warrenmj

Sounds like quite a few are having the same issue I originally started this thread with. After 2 Harrison radios and numerous calls to them, I gave up on Harrison. They never mentioned others were having the same problem I had and never brought up voltage or the internal fuse. They kept saying it "must be a grounding problem" in my car. I just recently installed a Retrosound and it works great.

BigT-65

I am not yet ready to toss my Harrison radio. I am going to try one more thing. Since the radio works all day in the garage with the car not running, I have wired the red wire that normally goes to the ignition directly to the battery connection along with the orange wire. I am going out for a test drive in a little while. I will report back afterwards. I think this is going to work. Just have to remember to always make sure the radio is off when it's not being used.

BigT-65

This didn't work either. It always seems to take 3 miles or so before it shuts down. Maybe it's a heat issue.

toddalin

OK...,

What speakers are you using? It sounds to me like the impedience is a bit too low for the amps and this causes an internal thermal overload.

When I pulled the four Bose amps out of my '91 and replaced them with a pair of big JBL stereo amps (mounted in the right rear hatch where they can get hot) and interface unit (under the dash), the JBLs would shut down after a short while. I measured the Bose speakers at just 1 ohm each! (Which is probably why the Bose amps have a limited life span.)

I added a 1 ohm resistor in series with each speaker, and while this is not the optimal solution, it does keep the JBLs from shutting down unless I really crank them for an extended period on a hot day.

You can try to put a couple ohms in series with the speakers to see if this solves your problem. Use high wattage resistors (e.g., 20 watt rating) as would be used in a crossover network. Alternatively, use higher impedience speakers, or depending on your system, wire them differently for a higher impedience.

I bet this fixes it.

alexandervdr

A friend of mine had a problem with a brand new electronic VR spitting out too high a voltage.
Hooking up the radio to a separate and dedicated battery (does not need to be a big one) and drive around is another way to check if it's the voltage supply or something else. If the problem still's there, about the only thing left is the speaker system, although I could understand that to shut down the radio, but loosing the presets?

BigT-65

I am pretty sure it's not the speakers. The unit will play for hours in the garage with the car not running. I don't believe it's a loose wire, I have moved and jiggled every wire I could under the dash. I don't have any other electrical problems. The voltage spike sounds like a real possibility. Is there a device that can be placed in the circuit just before the power goes into the radio or right after it comes out of the regulator? Surely a good radio guy could fix this.

Gary's '66

Have you contacted Harrison about this issue and if so what did they say? Also, have you verified the voltage that you're getting from the regulator (l know you switched back to the mechanical unit) is not spiking over 15 volts? When the radio quit did you try turning on other accessories (headlights AND heater motor on HIGH) to see if the radio would come back on?

Gary

toddalin

If the impedience is too low for the amplifier circuit, the excessive current draw and related heat failure may not manifest itself in the garage. This is not to say that there is anything wrong with the speakers or the amplifier unit. Only that the amp was not designed to drive an impedience this low because the current requirement is too high.

Consider, when the engine is off or at idle, the battery is at 12.6 volts. When the car is running at speed, the voltage increases to ~13.8 volts or about 10%. Because the final stage of the power amplifier is probably supplied by the full voltage off the battery/alternator, it also increases by 10 percent and the current draw increases by 10%. Current = Voltage / Resistance

Next consider that out on the road, the engine is making noise, as is the suspension and wind. The result is that you turn up the volume (voltage), even if it doesn't sound louder, because it is masked by background noise. The increase in volume then further raises the current requirements and if the amp is not up to it, it goes into thermal protection (or burns out), even if this is some internal component (e.g., a voltage regulator), and not your "dedicated" thermal protection circuit that measures temperature on the "rail."

Thus, when the amp goes down, it is certainly possible that it can take down the internal power supply momentarily and screw with your settings.

Just for kicks, measure the d/c resistance across each speaker load at the unit with both wires disconnected from the unit. This is not the actual impedience, but will provide an indication thereof.

If it is voltage spikes, a big capacitor placed across the hot leads at the unit should suppress them and help the bass during the musical transients. These capacitors have come way down in price.

alexandervdr

This is what I would suggest:

1. connect separate battery to power the radio and drive around. If the problem is still there it's or the unit itself, or the speaker

2. if the problem is not there with a separate battery, then it's how the 12 V is delivered to the radio. Could be that the VR voltage is fine, but that it delivers spikes, and maybe your radio does not like that. Go buy one of these radio noise filters at RadioSHack. Not expensive and worth a try. If that did not help, consider a car charger for a laptop. These are actually regulated power supplies, and smooth out all incoming crap. Take one that does 12V and adequate amps. Radio Shack may have them , plenty on ebay like http://www.ebay.com/itm/Brand-New-80W-12V-Universal-Car-DC-Power-Supply-Cord-Charger-Adapter-for-Laptops-/261361658143?pt=Laptop_Adapters_Chargers&hash=item3cda5e691f. 80W may be rather low, I have seen 100W too. The Harisson radio says it can deliver 180 watts max power, but knowing how most manufacturers over rate their sound gear, take max power rather than continuous power, you may go a long way with 100W.

The point is that if you solve this problem, you will please many. Cause this issue has popped up frequently on this forum If I were not living 5000 miles or more from your place, I would join you and help you sort it out

warrenmj

This problem only seems to be happening with Harrison radios. It seems several of us have contacted them with the same issue, yet they were no help to me when I had the problem and it looks like they haven't been any help to others either. If the problem is inherent to THEIR radio, it seems they should have an interest in fixing it to make their customers happy, but that doesn't seem to be happening.

BigT-65

OK, I think we are finally onto something here. I contacted Vintage Audio Radio and K&C Harrison yesterday. Brandon at Harrison says that they have identified the problem as an incompatibility with HEI ignitions in Corvettes. They say that when Pertronix (they didn't mention the company name) changed their frequency in their units it caused the radio to cut off and on like it does. Now this is why I believe this is true. About 4 months ago my Pertronix II died. I called Pertronix and they told me that when I bought my unit they were recommending Pertronix II Igniter with a Flamethrower III coil. They later found out that this eventually fried the Ingiters. So they sent me a new unit. This took place at almost the same time I started having radio problems. Even though my radio has been out of warranty for about a year and a half, Harrison is going to replace it with one of their units that has been redesigned to remedy this problem. Do any of you other guys with this radio problem have HEI ignitions in your cars? If so, I think we have solved the problem. I will report my findings when I get the new radio put in the car.

BigT-65

ttt

warrenmj

I do have a Pertronix unit in my car, which is about 13 years old. Looking forward to hearing if this solves the problem.

BigT-65

On the way to my club meeting tonight I tried a little experiment. I completely isolated the radio from the car by hooking it up to a motorcycle battery. The radio still turned off and on repeatedly. So the signal is apparently not coming from the voltage regulator and must be traveling through the air, probably from the Ignitor ignition. This would also explain why it will play all day without the engine running and start screwing up while driving.

alexandervdr

If the antenna is grounded somewhere to the chassis, the radio is not totally isolated from the car.
But I assume the antenna is not grounded (I did not check how this is done in a C2, if someone knows...) , so a last simple test is to ground the radio to the car (have the minus of your motorcycle battery connected to the ground of the car). Just trying to eliminate the possibilities.

Milliamp

First lets break the problem in half, I heard a lot about the voltage regulator, is that the problem? Why not eliminate the cause and effect, first place a voltmeter in parallel with the radio and have someone watch it while you drive if it peaks at or around 15 vdc you then will know that the internal cb in the radio is taking you off line. There are things that you can install that would clamp the flow but I don't want to get ahead of my self. there are very many smart guys on this forum and I think most of them would agree that you try one thing at a time.
I seem to have the same radio and all I can get it to do is light up I am going to talk to Tx. tomorrow I have done all the trouble shooting that they told me to do so I can think its time to send it back. You guys are lucky at least you have music in the garage.