How can I "bench test" a Sapphire 1 radio?

[amishman]

I am buying an old Sapphire 1 radio and at this time, my single cab is not wired for the radio and is 12 volt and all. Knowing this radio is a 6 volt radio, I understand I need to buy a 12 volt to 6 volt drop device to eventually use this is my ride. Before I do that though since it will be some time before I install in my ride, I want to test the radio to make sure it works. I have connected radios before in newer vehicles but do not want to blow up my sapphire so wanted to make sure grounding and all is done right. So, here are my questions.

#1
Is there some ac adapter or box that I can buy at Radio Shack that allows me to power 6 and 12 volt devices on a bench? Please offer info on what I need to buy on this to power the radio. I would prefer a box that offers 6 and 12 volt so I can test more than just one 6 volt Sapphire. I may have a 12 volt radio later on that I want to test also.

#2
Proper wiring? I believe the Sapphire has 2 or 3 wires coming out of it (at least that is what the picture looked like; I don't have the radio yet). Probably one "positive" lead, one "negative" lead, and one speacker wire. Not 100% sure on this. I think there are different grounds. One type you just connect the "negative" lead to some ground screw iin your ride? Other type I guess to the negative on the battery. Not sure so just want to make sure I ground the radio proper. So "positive" to positive power, "negative" to negative/grouund source (what would that be?), and speaker wire to speaker. I guess I also need to connect a small external antenna to get a signal also?

#3
Any difference when I install it in my single cab? Do I just find a positive coming off the fuse box, find some negative to ground it to (where?), and it should work?

Any help for me would be great!

Thanks in advance. I just want to make sure the radio works before storing ot for later install.

[NAES]

buy a rheostat (SP?) from the Shack and turn it all the way down and connect up your radio, speaker and battery.

When your ready to go, turn the radio on, connected to a speaker and then turn the rheostat up a little at a time and see if it fires.
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[Fish]

I use my old 12 volt / 6volt battery trickle charger to test stuff all the time. As long as you don't try to draw too many amps you're ok. Or you can buy a "6 volt Power supply" at radio shack for ??
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[EverettB]

Yep, I use my 6-volt battery charger, set on the low setting.

I would ground the body of the radio too, either from the back of the radio or twist a wire onto one of the poles because those might ground out on the dashboard when mounted.

Connect the ground wire to the ground of the battery or to a ground source on your car. It doesn't matter which. Normally it would go to a ground screw on your Bus, not the battery.

The speaker wire goes to the positive on the speaker, then just connect the ground on the speaker to the same ground as the radio.
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[dstefun]

[amishman]

I thought the AM Sapphires only drive one speaker in the single cabs that was mounted under the dash. I have one of the the 5" speaker brackets to connect the speaker to. Question is, if I have only one speaker, but I have two brown speaker wires coming out of the radio. Do I just use one? Which one? Need more info on how to connect both brown wires if they supposed to be connected someplace. Does one connect to the + on the speaker and the other the "-" ?

Thanks

thomas

"2 brown wires (looks like lamp cord) - speaker connections"

[Scotts 63 23]

Amishman,

Your Sapphire I drives one speaker. Connect the two wires (brown lamp cord) to the two terminals on the speaker. You're done...

Scott

[coad]

You can also just go buy a cheap lantern battery (the big boxy batteries) for 3-4bucks. They're 6V and will power the radio

[Scotts 63 23]

[amishman]

More questions. I just purchased a 6/12 volt battery charger. Figured I could use it anyway down the road. My unit has one 6 volt setting, 6 Amp 6 Volt, and two 12 volt, 2 Amp and 6 Amp. My question is will the 6 Amp 6 Volt setting be OK for the Sapphire 1 or is that too much? I do not want to blow up the radio. 2nd question, the radio I have came without the fuse and fuse holder. I will buy a generic one tomorrow. What fuse should I get. 2 Amp OK or 6 Amp or ?? Need guidance on this. I guess if 6 Amp is too much, I will have to buy the latern radio like someone suggested and try that.

BTW, when running a radio on the Battery Charger, should I see anything on the built in ampmeter? I would think that only shows something if connected to a battery but wondered if I should still get something on the Ampmeter when driving a radio.

Thanks

Thomas

[dstefun]

[amishman]

More battery charger issues. I am not having any luck testing a different radio using this battery charger method. Battery chargers have an automatic shutoff so when the battery is all the way charged, it shuts off. I have a feeling this is why this is not working to power my radio. I grabbed my multimeter and turned it on to read DC voltage and thought if I had the battery charger turned on to either 6 or 12 volt mode, I would get a reading of 6 or 12 volt on my meter. I get nothing. Like it is getting no power. So either my new battery charger is DOA or maybe it does not work unless it reads some juice from a battery? Kind of new to this so seek assistance. So from you users of the battery charger method, how did you get past this problem or am I not on the right track here.



Thanks

Thomas

[dstefun]

My battery charger is ages old so I don't have that problem, but yes, the newer ones that shut themselves off probably need a load on them to work, and the radio just isn't enough of a load. Try connecting the charger across a headlight bulb - that should be a good load.
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[j.pickens]

dstefun,
You are giving some excellent info. there.
One word of warning, though.
Be sure the radio is well grounded with a wire which will not come unattached.
The quickest way to blow out these radios is to power them, and then intermittantly disconnect the ground. This creates a capacitive charge which will blow the transistor(s) in a fraction of a second.
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[amishman]

I do not follow the bulb recommendation. Can you explain how I do this. I happen to have a extra break light bulb lying around that I could use. would that work. What do I do?

thomas

[amishman]

Couple more questions... Is the negative lead on a battery considered the same as a "ground"? Therefore, when I am bench testing my radio, and do not have a metal surface in the car to connect the ground wire to, if I connect a wire from the ground to the negative on the battery, is that OK?

Lastly, how many AMPS do I actually need to just power the radio to confirm it works. I see Radio Shack has these small AC to DC adapters and they are all low amps but all I want to do is test or play the radio at low volume so would a 1AMP 6V DC Adapter work for me. I would think yes but do not know if there is a minimum amp the power needs to be at for the radio to power.

Thanks

thomas

[Scotts 63 23]

Connect the negative lead on the battery to the threaded post on the back of the radio.

Just get the lantern battery. They're cheap. I've had mine for a few years and have tested quite a few radios. It's very straight forward with the connections and they are easy to find.

Scott

[amishman]

Thanks for all the help. I tried the 6 Volt Latern Battery option and it worked for me. $5 for the batery. I have no other use for the battery now but I guess as long as it has some shelf life, will use it later again.

Thanks

Thomas

[Scotts 63 23]

Amishman,

I throw my 6 volt battery in my backpack at swaps to test radios. It kind of freaks out a vender when they tell me the radio works and I whip out my battery...

Scott

[EverettB]

This is a super old thread but I wanted to add some information:

I was recently testing two 60/61 Sapphire Is with the trapezoidal buttons and I noticed both of them do not work well off my battery charger.

A hum was produced and the speaker was booming in/out, like it had massive feedback.

Both worked fine when tested with a normal 6-volt vehicle battery.

My later Sapphire Is, 62/63, worked fine off the charger.
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