Stryker 955 AGC Timing Circuit

[drifter291]

Well here is the agc circuit that Shawn sent me from Stryker if anyone wants to play with it? I am not sure if the timing will help with the overload though. But there it is - The circuit is in the attached file

Report back your findings if you work on it.

 

[drifter291]

I have gotten another 955 a few days ago which was the same as the other one with the distorted ssb.

I tried a 100uf capacitor which seems to be the standard that people use on other radios for agc it didn't really seem to do anything at least to my ears.

On a whim I stopped by Radio Shack last night and looked around and got a 240uf capacitor. I installed it last night and it does seem to make a difference. I still get the distortion BUT doesn't seem to be as bad and when I back off the RF gain it seems even better. which is something that didn't even seem to help my first one unless the rf gain was turned about all the way back where you could hardly hear anything at all and still have distortion. I wonder if going even more 300 -400? uf would be even better?

I haven't messed with the resistor in the circuit as I am too afraid to do as it is so tiny I am afraid I couldn't solder something in and mess up the board.

 

[drifter291]

One other thing make sure you get the leads correctly or you will fry something

 

[fogdog]

Totally by mistake I figured out how to do this mod without even opening the radio case.

I live at about 140 above sea level on the coast and my radio picks up everything. So I was up Turkey hunting last week, and in the late afternoon I jumped in the truck and turned the radio on. The elevation was around 3500', but I was in a bad location. I was surrounded by mountains on every side.

Anyway's to make a long story endless, I tuned to 38 LSB, and heard some guys from Australia talking back and forth, and there was absolutely no background noise. I thought my radio was broke. I checked a few more channels up and down, and made 2 contacts to Those guys in Australia. At this point I really did think the radio fixed itself. I mean every frequency was quiet. Stupid me. I was hoping it fixed itself, but when I was leaving and slowly losing elevation and getting closer to civilization I realized the elevation, lack of electrical infrastructure, almost 0 people was the reason for no overload. Damm! Oh well now I know how a radio should sound.

 

[drifter291]

The thing is not every signal does it. I can have a very loud signal almost pegging the meter and no distortion whatsoever then another one may have it. I would say no big deal they are strong BUT I can have a signal of s4 and sometimes have the overload??

It does seem better with the AGC being slower now I did the capacitor at 240uf (as 100uf didn't seem to do anything) then I added a switch on the side of the radio so I can switch between the 240uf capacitor and a 470uf (I thought maybe since 240uf helped some that something higher might even help more) . I cant really tell the difference between the two though. I wonder about the resistor if it would make a difference but it is so small I am afraid to try that.

I have also seen mods for the Anytone 5555 early versions before the company fixed it and the mod showed the same capacitor in basically the same place to change but also showed a couple of other points to change a couple of resistors. The boards are very similar I would love to be able to figure it out. I have seen a couple of videos of the anytone doing the same thing and then seen with the mod and it sounded like it should.

I might just live with it for the time with the capacitor changed until maybe I can see someone come up with a mod for the stryker then maybe find someone to perform it completely for me. I ok with soldering regular size parts but the surface mount size scares me.