My Grundig G3 had developed the sync detector issue, as it is from the first run SN# 472. It seemed to work well when I got it, but over time, I guess due to the component values settling, the sync got worse and worse, and finally settled into the usual 1 khz low. Since I purchased the unit on eBay, there was no warranty, and it is the 3rd unit I've had, and I didn't feel like trying to work something out with Eton. Everything else is great about it, sensitivity and selectivity, and the MW is clear, strong and as birdy-free as I suppose it can be. So, surgery time!
Plug in the correct 8v 200ma ac adapter, and take out the batteries. Unit disassembly is strait forward. 6 screws on the back (the ones with the arrows) are removed, and one in the battery compartment. DO NOT REMOVE THE ONE THE SCREW HOLDING THE WHIP ANTENNA!!! Once apart, remove the 7 (I think) screws holding the button and display board. You'll have to maneuver the halves around to get to all of the screws, there are wires from the VCO, speaker, and the whip, and the ribbon cable from the button board is short. Refer to pictures posted for what final disassembly looks like. I pulled the button matrix out and fitted it where it would be when the radio is assembled. Tune to a strong station (I live in the ATL metro, so I used WSB 750) and turn on the sync.
Now, locate c113, a small white variable cap to the left of the ribbon cable, and turn it until the voices are clear! I would suggest using headphones for this. Peak using the S-meter, and check both upper and lowers sidebands. Reassemble the radio.
After the repair, ssb performance is still quite good. ECSS is still possible, and effective. Nothing else seems to have changed performance-wise. The sync will occasionally loose the lock and start wailing, but turning off the sync and turning it back on will correct this. I guess time will tell, but I think this is it! I'll be watching the group if anyone has questions or comments. I'd like to hear how this works for others!
Chris
Chris - This is good information. I see you also posted this at the Yahoo Grundig_G3 group. I'm sure the folks there will be very interested in this fix, since quite a few G3 units seem to achieve sync lock only at 1 kHz low or 1 kHz high.
Eton should give the G3 more "sync width" -- in other words, allow it to lock over a range from 1-2 kHz below to 1-2 kHz above the carrier frequency. This is the way most other radios with sync behave.
Posted by: Gary | April 22, 2010 at 10:44 AM
Incidentally, how easy is it to replace a speaker on a portable radio?
I have a radioshack analog tabletop whose FM reception is just as good as my S-350-DL (32.99 at the Shack). Nice durable casing too. But the speaker sound is just horrible. To those who know - is this an easy upgrade?
Posted by: Carlos | April 23, 2010 at 04:37 PM
Gary- I get the feeling that Eton was trying something new and different with the G3 sync, but fell short. It would have been easy to emulate the sync circuit on the 2010 or 7600gr, unless there is a limitation on the chip that the radio uses.
Carlos- Provided you can find one the same size, it should be a very easy fix. Should be easy to find speakers that can handle more power, and maybe test some with different ohm ratings, it can only help battery life presenting a smaller load.
Posted by: Chris | April 23, 2010 at 10:15 PM
Thanks for posting this Gary and Chris! I just purchased a G3 at a local RadioShack and discovered this problem on a 8xxx series serial number. In about ten minutes I was dead on frequency again with sync working as it should again.
Posted by: Dave, K9DV | August 01, 2010 at 03:01 PM
Thanks for the info!
I screwed up mine somehow while fixing it, but the pictures helped me fix it.
Posted by: CVSoft | January 29, 2011 at 03:33 PM
Thanks a lot for this. I have a recent one in the 10xxx region, and it suffered from this problem. Now it syncs to even the weakest stations on the MW band.
The variable capacitor was incredibly small, to the point where I didn’t have anything I could use to tune it. I got a cocktail stick and used a knife to get a straight flat end on it. Using that it was fairly easy to tune it. All it needed was a slight turn anti-clockwise.
Posted by: Martin Payne | June 30, 2012 at 05:42 AM
Hi.My Grundig G3 is suffering this weird symptom: When I get the AC jack connecte it does not show the AC icon. At first I was able to get it connected by moving the jack around or pressing it hard, but after a while it just does not show the AC any more. Therefore I just have to run it on batteries. Does any one know what the cause may be? or how to fix this problem. I just love my litlle radio and don't know what to do about this.
Posted by: Edgar Allan Valencia | October 21, 2012 at 04:40 PM
I have a problem with my G3 not running on batteries. It works fine on the adapter, but when I try to turn it on with the adapter disconnected the radio appears to reset. I've tried this with new batteries and the same problem occurs. Any ideas? Thanks!
Posted by: David Stewart | September 04, 2013 at 09:33 AM
I have the exact same problem. It defeats the purpose
of purchasing a mobile radio.
Posted by: Ralph Henman | May 10, 2016 at 04:14 PM
Con el tiempo necesitaréis cambiar varios condensadores electrolítico trabajando por encima de su valor. Tenedlo en cuenta.
Posted by: Javi | May 20, 2023 at 12:56 PM