Very Weak Modulation Galaxy DX77 HML

[wildchild455]

Definitely sounds like it is in need of a TX chain alignment. Off the top of my head, I believe it's L44, L43, L42, and L40.

Replace TR51 with a TIP36C.
Replace TR50 with a TIP42C.
Replace TR41 with a TIP42C.

These transistors are much beefier than the originals. They are also more cost effective too. This isn't necessary, but helpful, and you will see more output, if the radio is aligned properly.

The TX chain alignment is necessary, though. As Robb suggested, you'll need something that can produce a steady 1khz tone, a ceramic or plastic screwdriver, and a good wattmeter. Adjust those 4 cans and that should net you more output, IF they are out of alignment.

My Superstar 3900G had the same issue as yours until I did a good TX alignment on it, now it does 50W PEP on SSB and has excellent forward swing on AM.

Good luck.

~Cheers~

I did try t adjust but it still did the something there's got to be some component that's going bad or getting weak and hasn't gone all the way out maybe radios can sometimes make a preacher cuss when things go bad.
I don't have any type of alignment equipment a tone generator a scope all I got is a watt meter a dummy load and a digital VOM
Bad thing is there's not a shop within 65 miles of where I live to take it to I dont knoew might start looking online and ship it off to a tech to get it repaired my old hands and eyes aren't what they use to be

 

[Robb]

I don't have any type of alignment equipment a tone generator a scope all I got is a watt meter a dummy load and a digital VOM

That is all you need to do the peaking of the coils. That, and a nylon/plastic tip tuning tool - that is a MUST.

Tone generation? All you need is you computer speakers and this:

http://www.freesound.org/people/klangfabrik/sounds/28636/

Be SURE to adjust the driver and final first using your VOM/DVM (preferred) for the mA reading.

 

[wildchild455]

I tried but no luck still got same problem am at a loss here on this one

 

[wildchild455]

I tried but no luck still got same problem am at a loss here on this one

Update contacted a friend that had some old radios and he had a 2SC2538 pre driver took it out installed it and its some better it looks like that the driver is kinda weak going to order those two parts tomorrow
Thanks to all

 

[Robb]

Peak the coils after you replace your parts. There will be a huge difference in the modulation product when this is done. As a rule; not an exception. If you don't have a nylon tip tuning tool, make one out of a piece of scrap hardwood. It might take a little time to make/do, but the finished product is definitely worth it.

Remember to peak the the coils in SSB mode at a low power setting after the driver and finals have been adjusted as it makes the greatest difference even if you only use AM most of the time . . .