2510 power seems to be dropping. Final or driver?

[Rogerbird1]

HI,

It is normal to see a lower PEP when adding an insulator.

The only explanation I have for it, is that with the insulator, you are no longer suceptable to the "RF Feedback Ground Loop" Problem, which I believe may have been causing 'false' PEP readings (higher than Actual) due to the generated noise on the signal by the ground loop.



I had one customer that had the same issue of 'fading' output power, and After installing the Insulator he complained of the lower power reading than he was used to..I explained my theory to him and he did some on air testing and found that a regular neighbor contact of his actually reported Higher readings from the repaired radio than from before.



Your previous problem may have been a defective final or some other circuit problem that you corrected when you re-installed the replacement final.



For a little more power, try paralleling C127 with a 680pf capacitor,

or try the 'Better High power mod' without changing the 477 final.

I find this usually will compensate for any measured power loss after an insulator install.



Roger




</p>

 

[Rogerbird1]

HI,

It is normal to see a lower PEP when adding an insulator.

The only explanation I have for it, is that with the insulator, you are no longer suceptable to the "RF Feedback Ground Loop" Problem, which I believe may have been causing 'false' PEP readings (higher than Actual) due to the generated noise on the signal by the ground loop.



I had one customer that had the same issue of 'fading' output power, and After installing the Insulator he complained of the lower power reading than he was used to..I explained my theory to him and he did some on air testing and found that a regular neighbor contact of his actually reported Higher readings from the repaired radio than from before.



Your previous problem may have been a defective final or some other circuit problem that you corrected when you re-installed the replacement final.



For a little more power, try paralleling C127 with a 680pf capacitor,

or try the 'Better High power mod' without changing the 477 final.

I find this usually will compensate for any measured power loss after an insulator install.



Roger




</p>

 

[Rogerbird1]

Yep, the 497 is a direct replacement for the 477.

No need to replace the 2086.



You may want to consider the "Better Hi power mod",

I have done part of that mod without replacing the final or the pre driver, and noticed a marked improvement.



Roger




</p>

 

[Rogerbird1]

Yep, the 497 is a direct replacement for the 477.

No need to replace the 2086.



You may want to consider the "Better Hi power mod",

I have done part of that mod without replacing the final or the pre driver, and noticed a marked improvement.



Roger




</p>

 

[Detail man]

Put insulator behind stock final 477 and had a strange occurence. Previously the radio seemed to have dropped from max of about 35w pep to about 25pep. After installing insulator radio malfunctioned like a bad final. It got extremely hot and chared C116 and L123 was really hot. I replaced final with used 477 I had around and and c116and now it functions ok but max out is roughly 18 to 22w pep am and ssb.

It has variable power and the mike gain mod from Rogerbirds site. Think the driver could be weak? Voltages on driver and final are correct and bias is set properly.

Possibly coupling cap weak?

Or is all this about the norm. Radio did used to be a lot peppier. Just wanted some advice before makin wholesale changes.

All help is appreciated.



Detailman






</p>

 

[Detail man]

Put insulator behind stock final 477 and had a strange occurence. Previously the radio seemed to have dropped from max of about 35w pep to about 25pep. After installing insulator radio malfunctioned like a bad final. It got extremely hot and chared C116 and L123 was really hot. I replaced final with used 477 I had around and and c116and now it functions ok but max out is roughly 18 to 22w pep am and ssb.

It has variable power and the mike gain mod from Rogerbirds site. Think the driver could be weak? Voltages on driver and final are correct and bias is set properly.

Possibly coupling cap weak?

Or is all this about the norm. Radio did used to be a lot peppier. Just wanted some advice before makin wholesale changes.

All help is appreciated.



Detailman






</p>