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A very Merry Christmas to all my forum friends!
It's hard to believe that at this point, some of us have known each other for over 20 years!
Here's hoping everyone gets a new electronic gadget under the tree this year!
LC
ok well then that's not the problem.
I apologize if this seems pedantic but have you done a continuity test from the body of that transistor to the metal chassis of the radio?
LC
VSWR,
something you said in one of your posts prompted me to ask, what color is the heat sink compound you are using?
you said "top of the line CPU compound" and many times that type of compound is conductive.
if the compound you are using on that TO3 transistor is grey/silver, then i would...
ok that's the power supply.
Something is wired wrong, or a bad component, or maybe that transistor was mounted improperly and is making contact with the chassis?
(i would figure that would pop it but maybe not)
LC
Are you talking about the TO-220 transistor that is mounted to the shield wall of the PLL section?
if so, there is a TSB on this. It involves moving that transistor (TR36) and a resistor (R153) to another area where it can be connected to a heatsink.
move the resistor as well and solder it to...
Mike, what radio is that with the dual gate mosfet front end?
Brandon, dual gate mosfet front ends were the dream for many people about 20 years ago or so and there was a guy named Bill Good who designed a way to mod the 148gtl/2000gtl to use one.
I never saw one but apparently it worked very...
Hawkeye, what you are experiencing is common with this and similar board designs.
The info im giving you came from a Galaxy factory tech many years ago.
the symptom is a very noisy receiver that will exhibit an S meter deflection even with no antenna connected.
the problem is the antenna coil...
I played around with the schottkys and the 2999 transistor back when everyone else was, and while initially i thought i noticed a difference in the sound of the background static, i believe it was just a perceived change and they didn't really do anything special.
I stopped messing with them...
thank you for drawing that up Brandon!
Where did you get "Ltotal" value from?
was it just a random guess to use for the example?
now we need to see what value cap Carl put in there!
LC
best of luck finding enough 20LF6's these days.
if you can't find them, one option is to get a high current 6 volt transformer and use it for the filaments so you can run 6LF6's.
LC
the two lamps are wired in series as shown here:
this means that if one goes out they both go out.
here is a link to that schematic:
https://cbtricks.org/radios/rci/rci_2950/graphics/rci2950_cpu_dpt295040z_sch.pdf
Here is a pic of where the lamps are located. if you're not sure of your...
yep, it was known as the "supermod".
its a way to lower the deadkey while keeping the max modulation swing.
you should see two wires coming from the kit that go into the PC board where a diode was. its a rectifier diode.
the idea is that each additional diode put in series with this diode...
here's a snip of the schematic for anyone wanting to play along.
This is for the 69 base.
This shows that VR12 is for both pre-driver and driver, and VR10 is for both finals.
so it would seem that it's correct to set each of them for 100mA above quiescent current, but Nomad has me...
here ya go!
https://www.worldwidedx.com/threads/oh-no-mr-bill-rci2995dx-shorted-q66.265942/#post-811267
as always thank you to NomadRadio for these great tutorials!
LC
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