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cobra 148 mosfet irf 520

rainmaker

Member
Jul 5, 2011
7
0
11
has any one tried using the irf 520's insted of the erf 2030 ? I tried using them and had bad luck. i know i need to up grade my regulator since it blowed but what else is wrong i wonder? I changed bolth tr 36 & 38 with the 520s to make it more complient. I fallowed the instructions to the lettter off of cbtricks. but i did find that it dosent state exactly witch side of r180 to solder it to. i assume the leg side of the vr adjustment. any one got an idea or a better lay out for this mod? :bdh:
 

There is no real electrical difference between those two components.

Did you install the correct companion device ('EN-369FN') with the MOSFET?

inside_en369dr.gif


You can make the companion device yourself (been there; done that).
Or you can buy them pre-made too.

CBTricks MOSFET Experimenter's Information Notes

http://www.cbtricks.com/miscellaneous/fet_papers/ekl/graphics/erf2030_148gtl_mod.pdf

The MOSFET replacement is not a direct replacement, as I am sure that you are already aware of that.

Have gotten MOSFET devices thru the mail that had failed.
They are extremely sensitive to static! . . .
 
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cobra 148

that the same set up i looked at for the mod. i just used the 520s insted of the 2030s i went back and checked my work and replaced one of the mosfets and the am regulator that blowed. now I have lost voltage @ tp 7 & 8 during TX. hum. now whats wrong ? is there realy much difference in the 2030 vs. 520 ?
 
that the same set up i looked at for the mod. i just used the 520s insted of the 2030s i went back and checked my work and replaced one of the mosfets and the am regulator that blowed. now I have lost voltage @ tp 7 & 8 during TX. hum. now whats wrong ? is there realy much difference in the 2030 vs. 520 ?

There is no difference between the IRF and the ERF. They still need to use an insulator and heat sink compound. I would remove the MOSFET and check voltages on the board.
 
148 insolators

yup i installed new ones to be safe. this is one of the new 4 pin 148's same but diferent. I have 14 volts at idle @ tp 7 & 8 and checked d44 still no am power but i do have ssp power. only 15w. pep.
 
They are close enough... Chip at RCI says that the ERF2030 is kinda in between the IRF510 and the IRF520. I am not sure as I have not reviewed the specs sheets on all of them. But I DO know that people have used the IRF510, IRF520 and the ERF2030 in the same application with similar numbers on the meter.
 
I hope your 148 had blown finals to begin with. Makes no sense to do that to a working 148 in the first place.
 
148 no voltage @ tp7&8

it was working but it had 2 2166's it and i wanted to up grade my radio.
now i half to find why ive lost voltage at this point.
 
The 2166 is the driver, should have a 1969 final. Just put one of those in and be done. Such a fine radio does it really need an "up-grade"?
 

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