GP-300 Memory(?) Problem

[yagermeister]

I have a 16 Ch. VHF GP-300 that's having serious problems. Had it programmed and everything was working great, including a scan channel plus a bank of channels setup for Quik Call II signaling. Now the scan doesn't work, the Quik Call II channels seem dead and some channels are not where they are supposed to be. Had the programming checked, and everything looked O.K. Do these have an internal battery that needs periodic replacement or is the memory likely corrupted?

[Will]

The GP300/P110/GP350 do not have any "memory battery" in them.

Try to load your saved codeplug information into the radio.

[yagermeister]

We tried to load a saved codeplug but that didn't seem to help. As the channels were changed several times, an archive copy was kept (on 3 1/2 inch disk) each time, but no older copy so possibly the 3 1/2 inch backups are corrupted also. Have another GP-300 but it has the low bandsplit so we can't clone it.

[wavetar]

If the RSS doesn't have a problem with reading the radio, or your floppy back-ups, it's likely not a corruption issue. Going with the simplest deduction, it sounds like you may have a defective channel selector switch.

[WB6DGN]

Now the scan doesn't work, the Quik Call II channels seem dead and some channels are not where they are supposed to be.

My suggestion, replace the channel selector switch. That was a known common issue with these radios AND a very inexpensive fix.
Tom DGN

[yagermeister]

Would I have to take a channel selector switch off another radio, or can these parts still be found?

[WB6DGN]

Would I have to take a channel selector switch off another radio, or can these parts still be found?

The best choice would be to use a new switch if they are still available, which I suspect they are. I'd check with escomm who frequents this board. My experience with him has been excellent and he would be able to tell you if the switch can be ordered from Mot. As of about mid 2005, when I retired, the cost was about 15 dollars for a new switch. Of course, if it is no longer available, you could use a known good switch from another radio. Be careful, though. The switch can easily be damaged by improper removal. It is soldered on both sides of the board, as well as in the plated-through holes, and has the tendency to pull a contact out of the switch body if not properly removed. With a defective switch, that doesn't matter, but if you intend to reuse it, it requires much more care. The usual failure mode is to repeat channels 1 and 2 every third position and to "lose" the settings in between, though other strange combinations are possible. Hope this helps.
Tom DGN

[35echo]

Yagermeister,

4080710Z21 SWITCH, FREQUENCY $12.08 List

Still available on MOL

Regards,

Allen

[yagermeister]

What are the chances of ruining the radio while desoldering the old switch and soldering in the new one? If it's a tough job I may try to get an electrician friend to do it. He has a good soldering station wheareas I don't. Thank you all for your help. I would have never figured it was a bad switch, but more likely an IC that had gone bad.

[WB6DGN]

If you are not experienced in desoldering parts from a multi-layer board I would strongly recommend someone who is. As mentioned before, the switch contacts are soldered on both sides of the board AND in the plated-through holes. Pulling that trough-plating out could very well make your radio a "parts donor". The proper tool to use is a vacuum desoldering station. We did have one guy at the shop who would do it very successfully with solder wick but you wouldn't get ME to try it. Maybe someone on the board would volunteer his/her services for a reasonable amount. That would be the best way to go. My shop is a disorganized mess after a fairly recent move or I would offer. Maybe as a "last resort", but I am sure there are others here that will do it for you.
Good Luck,
Tom DGN

[yagermeister]

Got a new 16 ch. switch, and took the radio to a local commercial radio business. Just using some desoldering braid and a fine point soldering iron he had the old switch out and the new one installed in less than an hour. Very nice work. You can't even tell that it isn't the original swich by looking at the solder points on the board. He also did it for a very minimal charge. Now everything is working correctly again. Thank you very much for helping me solve this problem.
Forgot to mention that once I opened the radio up you could see the switch moving. The solder joints were O.K. but the switch itself had come apart.