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Another Saturn bias issue

Is it possible that the very low resistance you measure between the base and emitter is due to the VR's being set to zero? I know there is still a 1ohm resistor that should be showing up, but maybe reverse the ohm meter leads so its not letting the B-E junction share some of the meter current.

If this explains away the low resistance, I think Bayou might be right about the bias diode's Vf.
 
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Got it...

Output now:
AM carrier - 1w up to 12w
AM swing - 55w PEP
SSB - 45w to 50w

Reworked entire driver/final section, replaced all three bias adjustment VR's, triple checked solder work.

Factory bias network still intact, except I used 4148 diodes for bias diodes.

Radio reports on the air is "It's loud hawk and has a strong carrier".

Thank you guys...

Now I'm gonna write down the steps to do the bias as y'all said on my personal Saturn. My Saturn works great as it is, but I'm gonna use mine to experiment with this bias rework y'all posted.
 
I have one of the china component testers,

They work ok with small transistors but don't have enough voltage or current to properly turn on larger transistors & useless for pill style devices,

You can test several with widely varying hfe on the china tester but they often give the same output power when tested in a rf test jig at proper voltage & current,

hfe for a 2166 is tested @ 10v & Ic of 100ma, you won't see much gain with low voltage & only 6ma of collector current.
 
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bob85 said:
I have one of the china component testers,

They work ok with small transistors but don't have enough voltage or current to properly turn on larger transistors & useless for pill style devices,

You can test several with widely varying hfe on the china tester but they often give the same output power when tested in a rf test jig at proper voltage & current,

hfe for a 2166 is tested @ 10v & Ic of 100ma, you won't see much gain with low voltage & only 6ma of collector current.
Click to expand...
Now I need to figure out what current my little china tester runs at. I guess I never really thought of that. This BSIDE ESRPro2 runs on a 9v battery. It is currently at 8.6v, it goes for a long time, until the battery gets down to 7.8v or so.

My 2166's hfe tests at 71 with that battery. I will have to continue to test that transistor as the battery gets lower to see if the results hold steady.

This is from the 2166 datasheet, so either my tester battery should have been dead two years ago or I have a really healthy 2166 in my parts bin.
1765918832186.png
 
Your tester may work ok but the lcr7 style testers just don't have enough grunt to work correctly with high power components.
 

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