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Tue Nov 02, 2010 1:14 pm

I purchased a Saphire 6v stock AM Dash Radio from a vendor on Samba for my 64 Vert. Not sure from whom now. I did it 6 months ago. I was told it was bench tested. When I got it I tested it to make sure it powered up. I installed it last night and only get static. I has 6.2v going to it. It is grounded. Has a new antenna hooked to it and I verified it is hooked to a the speaker in the dash properly. All I get out of it is lights and a wooshing sound at max volume. Does anyone know what I did wrong or is faulty? Could the speaker be bad? Could the antenna be unhooked inside. It sat on a shelf for 6 months.

Tue Nov 02, 2010 2:09 pm

I'm in the same boat. I purchased a refurbished one...paid big bucks. Only get static at high volume setting. Search for the radio brochure/instructions. It has a procedure for tuning the radio using a small screw driver through one of the case holes. I still need to try that. I also have a new antenna & speaker, and wiring is correct.

Tue Nov 02, 2010 4:10 pm

ThorpS18 wrote: It has a procedure for tuning the radio using a small screw driver through one of the case holes.

If you have already made sure that the antenna and cable are new/good, then this is what you do. Scroll the dial until you find the weakest station, then using the screwdriver turn the dial on the backside of the radio. Hopefully you will be able to bring in the weak station better and in affect make all of the other stations come in more clear.
Oh btw, I would make sure that you are outside, not under anything and have a mostly clear day outside. I had the same problem with the Motorola in my 58 and was able to get good reception that way, but if only for some crappy talk radio stations. :wink:

Tue Nov 02, 2010 7:43 pm

Only get static. Could be the antenna. have you bench tested it? Yes you will have to hook some sorta antenna and speaker to it on the bench. At nite you should be able to get an AM station.
As far as adjusting the little screw near the antenna connection. Tune to the nearest 1400 AM radio station and then tune that littel screw for a stronger signal.

Sun Aug 25, 2013 11:21 am

I am looking for an answer to my reception issue, and ran across this thread. My problem is that the radio works, but the volume is so low, you can only hear 2 stations, and they are very quiet. However, if you leave the radio on, and walk out to the antenna and touch it, the radio booms to life, very loud, very clear. And you can find some ten stations, as opposed to the two you find when someone isn't holding the antenna.

This is with a six volt Sapphire am radio, antenna mounted to the outside of the car, plugged directly into the Sapphire. Thank you!

Sun Aug 25, 2013 11:27 am

I will cover a base in advance. It is not feasible for me to have someone jog alongside the car and hold the antenna, even though that may be the obvious solution. :wink:

Sun Aug 25, 2013 3:51 pm

You need to adjust the antenna trim as stale air mentioned above. The stations will not only come in clearer but will be louder as well.

stale air wrote: ThorpS18 wrote: It has a procedure for tuning the radio using a small screw driver through one of the case holes.

If you have already made sure that the antenna and cable are new/good, then this is what you do. Scroll the dial until you find the weakest station, then using the screwdriver turn the dial on the backside of the radio. Hopefully you will be able to bring in the weak station better and in affect make all of the other stations come in more clear.
Oh btw, I would make sure that you are outside, not under anything and have a mostly clear day outside. I had the same problem with the Motorola in my 58 and was able to get good reception that way, but if only for some crappy talk radio stations. :wink:

Look for more detailed instructions for your particular radio here in the radio manual archives. Most manuals have a antenna trim adjustment procedure.

http://www.thesamba.com/vw/archives/manuals/radios.php

Sun Aug 25, 2013 3:57 pm

Your radio probably has an antenna trimmer that tunes the radio to the antenna on the back of the radio. See step 8 at the bottom of the page. This is for a Sapphire II. (See Technical Section)

Sun Aug 25, 2013 5:18 pm

make sure you have a good ground between antenna base and car body...repaints can be a problem

Sun Aug 25, 2013 10:44 pm

I saved many radios with nothing but antenna trimming.
Don't forget to pull the antenna out all the way first.

Sun Aug 25, 2013 11:52 pm

Thanks everybody! That helps tons!

Mon Aug 26, 2013 6:01 am

I just became a member of "the antenna trimming club." It made for a substantial difference on my 6 volt Sapphire 1 radio. Thanks for the suggestion.

Sat Sep 06, 2014 12:17 pm

Volksworld,
Why is a good ground from antenna base important?
My wife's 66 bug has a Sapphire radio which appears to be factory.
A PO has installed a new antenna and when I raise the antenna I can tune in about 4 AM stations but the volume is very weak.
What if anything can be done to increase the volume?
I did trim the antenna with the small screw labeled antenna trim.
Thks,
Dwight
(caretaker of my wife's recently acquired 66 bug)

Sat Sep 06, 2014 1:09 pm

You may need to take the radio to a repair shop with the equipment to make internal adjustments or repair.

Sat Sep 06, 2014 6:51 pm

A related question; when cruising and listening to the am radio, I notice that intermittently, the volume increases significantly at times. It seems to somewhat correspond with higher engine rpm's, but also happens sometimes when the rpm's are not as high. It will get REALLY loud, and then the volume will drop off and be very quiet, and then later, the volume will surge again. Any idea?

Sat Sep 06, 2014 7:30 pm

AM radios are design with an automatic gain control circuit, AGC. If the circuit is not working you will experience the symptoms you described. If the AGC circuit is not working, as you drive the signal strength varies which causes the loudness to very.

Sat Sep 06, 2014 11:04 pm

I have a couple spare am radios. How might I identify and repair the AGC circuit?

Sat Sep 06, 2014 11:53 pm

panicman wrote: I have a couple spare am radios. How might I identify and repair the AGC circuit?

The AGC circuit parts are D1, C13, R13 and CE2A. CE2A is the first part to test or replace.
With the radio off, D1 should be about 0.3V with the DMM diode test function.
With a strong station the CE2A voltage is much lower than 0.99V.
Pull out the antenna, the voltage on CE2A should be 0.99V.
Test a good radio and record the two voltages.

Sun Sep 07, 2014 10:11 am

Great! Thank you. I may come back in the future with pictures to confirm I am looking at the right capacitors, diode,and resistor.

Fri Nov 28, 2014 4:58 pm

So, the diagram that matches my Sapphire I is the 1963 model (credit to theSamba for the diagrams):

So, is the acg circuit on this diagram C22, C21, R23, and M3?

It looks like I could just get those parts and directly replace them.

I don't have a "good" radio to make comparisons with. I pulled one of the extra radios out and have managed to identify the caps, resistor, and diode that make up this circuit, and I can certainly solder new ones in.

Any reason this wouldn't work?