Another radio falls victim of Bob's CB shop

[Handy Andy]

Then go back to the radio...

I'm quite sure that "sawtooth" waveform seen as output was from the final that is damaged, and the one unscathed may still be waiting for it's order to start working - remember what was uncovered so far.

Matched pair of a claimed "Match pairs" ARE REQUIRED if you run one single "EN1230 or EN369" part - else run two bias'ers to allow for each MOSFET to run on their own.

We found only one bias line feeding one ERF2030 - but the outputs were tied.

So by photographic evidence, the one ERF2030 that looks unscathed, the radio may have been operating only on one final MOSFET this whole time.

Review the work done to it. You may still have an operational ratio, becasue one finals Gate never got hooked up - it may have just been in a "free running" state running in proximity to the other final as a mirror of it - it may still work, although a "bit tempered".

 

[Low_Boy]

I bought three transistors. Two have the same gate threshold voltage. Those will be the two I use.

 

[Handy Andy]

Just remember when copper is heated - after it cools, it is even more fragile and brittle - exercise care when re-working that area - that discoloration shows tempering - so the copper foil in those traces has lost it's ductility.

 

[Low_Boy]

I can not find what they did. Replaced 2 finals. PEP. 80W from 2W 80W from 5W Avg 13W from 2W and 18W from 3W.

 

[Low_Boy]

We got it looking a bit more presentable. Doing about 60 low 70 high. Still seems like a lot of power but.... still is a bit over modulated.

 

[Handy Andy]

Wow, It's Alive!

Ok, settle down, let's get the patient back on the table before it leaks RF all over the floor and walls...

 

[Mk121]

Nice work low boy. It definitely looks better than before.

 

[Low_Boy]

Tomorrow the victim will get it's test run.

 

[Low_Boy]

Wow, It's Alive!
I

Ok, settle down, let's get the patient back on the table before it leaks RF all over the floor and walls...

I tried like crazy to get the burn mark off the board but no luck.

 

[Tokin]

Isn't big cheap watts what the people want?

 

[Rwb]

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I’ll play devil’s advocate here, Maybe you’re just overthinking this thing here, I know there’s the arguments for and against the “matched” sets. While I’m not saying they aren’t important, I am saying does it really matter in this case?

I know we want this perfect signal, we don’t want anything introducing harmonics or distortion into our signal. But is everything else going to be absolutely perfect to the point that an unmatched set will cause chaos? I love Magnum but it’s not like this is the Rolls Royce of radios we’re talking about here. You could argue that too, it needs all the help it can get and not something else to introduce an issue with.

But again, does it really make that big of a difference? Is the juice worth the squeeze? Is it worth all this time and effort for the end result?

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