I was thinking about swapping out a 2sc1969 with a erf7530.is this a direct drop in? Im kinda new at this.have done a dual erf2030 on another radio. was going to do it on a galaxy 959.thanks for any info.
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
erf7530 mod
- Thread starter chrlkeaton
- Start date
I have dual irf520's in my 959, There pretty straight forward to install. I think CBTricks has the conversion itemized, you can also pull the schematic on a new export with the dual or single mosfets, the boards are all the same just with the components labeled different. The irf520's are $0.75 a piece and they do a clean 35 watts (from Mouser)
As far as the erf7530 i have never looked into it.
I would get a PowerBand RFX-75.
Considering the trouble and materials; they can't be beat by going this route.
I would also keep the power output on it down low when setting it up - to keep it from premature failure.
http://www.cbtricks.com/miscellaneous/accessories/power_band/rfx_75/index.htm
Considering the trouble and materials; they can't be beat by going this route.
I would also keep the power output on it down low when setting it up - to keep it from premature failure.
http://www.cbtricks.com/miscellaneous/accessories/power_band/rfx_75/index.htm
Attachments
WARNING WARNING WARNING DO NOT ATTEMPT TO TRY WITHOUT READING COMPLETELY FIRST.
To chrlkeaton: I have done what you are looking into.
It depends on your skill as a tech. If you are pretty handy with reading schematics and a soldering iron it isn't that hard, but if you are not good with both or either then don't try it.
HERE ARE SOME THINGS THAT ARE INVOLVED NOT ALL STEPS INCLUDED. I TAKE NO RESPONSIBILITY OR LIABILITY IF YOU CHOOSE TO TRY TO FIGURE OUT THE REST OR ALL STEPS NEEDED. THE STEPS ARE ONLY FOR AN EDUCATIONAL IDEA OF WHAT IT WOULD TAKE TO DO THE PROJECT AND ARE NOT COMPLETE FOR A SPECIFIC REASON.
I preferred to have the erf7530 as part of the main board rather than a RFX75 myself. One way to go about it is. You can leave the galaxy bias circuit with pots and remove jumpers 101 & 102 add a coil to drain of Q48 then to mirror board. If you get the idea then you may be ok. The job is not for the faint of heart and you will need a larger heat sink like the style of the one that comes on the magnum s-80 series radios or it will get too hot. Do not put the dead key over 15 watts either. What the end result will be is a irf520 driving a irf520 then driving the erf7530. You will need to stretch coils near the ant, L36 and maybe L29, L30'& L31. If you are serious and have a little talent it is very possible. Also you will need to replace D88 D89 D16 & D17 with schotkey diodes like 1n6263 for stability. Good luck if you try this.
WARNING WARNING WARNING DO NOT ATTEMPT TO TRY WITHOUT READING FIRST. HERE ARE SOME OF THINGS THAT ARE INVOLVED NOT ALL STEPS INCLUDED. I TAKE NO RESPONSIBILITY OR LIABILITY IF YOU CHOOSE TO TRY TO FIGURE OUT THE REST OR ALL STEPS NEEDED. THE STEPS ARE ONLY FOR AN EDUCATIONAL IDEA OF WHAT IT WOULD TAKE TO DO THE PROJECT AND ARE NOT COMPLETE FOR A SPECIFIC REASON.
To chrlkeaton: I have done what you are looking into.
It depends on your skill as a tech. If you are pretty handy with reading schematics and a soldering iron it isn't that hard, but if you are not good with both or either then don't try it.
HERE ARE SOME THINGS THAT ARE INVOLVED NOT ALL STEPS INCLUDED. I TAKE NO RESPONSIBILITY OR LIABILITY IF YOU CHOOSE TO TRY TO FIGURE OUT THE REST OR ALL STEPS NEEDED. THE STEPS ARE ONLY FOR AN EDUCATIONAL IDEA OF WHAT IT WOULD TAKE TO DO THE PROJECT AND ARE NOT COMPLETE FOR A SPECIFIC REASON.
I preferred to have the erf7530 as part of the main board rather than a RFX75 myself. One way to go about it is. You can leave the galaxy bias circuit with pots and remove jumpers 101 & 102 add a coil to drain of Q48 then to mirror board. If you get the idea then you may be ok. The job is not for the faint of heart and you will need a larger heat sink like the style of the one that comes on the magnum s-80 series radios or it will get too hot. Do not put the dead key over 15 watts either. What the end result will be is a irf520 driving a irf520 then driving the erf7530. You will need to stretch coils near the ant, L36 and maybe L29, L30'& L31. If you are serious and have a little talent it is very possible. Also you will need to replace D88 D89 D16 & D17 with schotkey diodes like 1n6263 for stability. Good luck if you try this.
WARNING WARNING WARNING DO NOT ATTEMPT TO TRY WITHOUT READING FIRST. HERE ARE SOME OF THINGS THAT ARE INVOLVED NOT ALL STEPS INCLUDED. I TAKE NO RESPONSIBILITY OR LIABILITY IF YOU CHOOSE TO TRY TO FIGURE OUT THE REST OR ALL STEPS NEEDED. THE STEPS ARE ONLY FOR AN EDUCATIONAL IDEA OF WHAT IT WOULD TAKE TO DO THE PROJECT AND ARE NOT COMPLETE FOR A SPECIFIC REASON.
The schematics you will need to complete the steps if you choose to do so will be the radio's final section change to mosfets and the schematic of RFX75.
http://www.cbtricks.com/miscellaneous/fet_papers/mosfet_conv/graphics/6900xxx_am_fm_mosfet.pdf
http://www.cbtricks.com/miscellaneo...band/rfx_75/graphics/rfx75_schematic_rev4.pdf
If you compare both designs you should be able to figure it out. One more hint in the radio remove the 560 pf silver dipped mica at c199 and do not change c200 which is a 103 disk.
http://www.cbtricks.com/miscellaneous/fet_papers/mosfet_conv/graphics/6900xxx_am_fm_mosfet.pdf
http://www.cbtricks.com/miscellaneo...band/rfx_75/graphics/rfx75_schematic_rev4.pdf
If you compare both designs you should be able to figure it out. One more hint in the radio remove the 560 pf silver dipped mica at c199 and do not change c200 which is a 103 disk.
If you do need to replace a burnt 1969, there is a drop in.
for example from ST microelectronics: 2ST1480FP seems to be slightly better than 2sc1969 and is a drop in.
But if you want more power, you would be more happy with a small external power amplifier.
for example from ST microelectronics: 2ST1480FP seems to be slightly better than 2sc1969 and is a drop in.
But if you want more power, you would be more happy with a small external power amplifier.
If more understood that, there would be one hell of a lot less 2 and 4 pill high output radios sold.
Wha?
This is a cheap AND available replacement for the 1969?!?
First time I heard that
you should mention the reason that your RFX75 doesnt put out the rated output so that you dont give someone the wrong impression.
LC
It should be. The requirement is to match or exceed the required specs of 1969.
Such as collector-base voltage, collector current, transition frequency at least three times CB frequency, and desired power dissipation.
The package needs to be TO-220 if drop-in is required.
Thats why 2ST1480FP is a viable drop-in replacement.
Vcbo: 80v
Ic: 5A
Pd: 25w
Ft: 120MHz
Yet, TO220 is not a good package for RF. At 27MHz low power its passable, but the market for this is not enough for semiconductor business.
Another alternative is something like ON Semi MJD44H11 parts. Should give better performance, and probably cheaper, but would require board layout for TO-252 package.
(transition frequency is also called gain-bandwidth product, unity gain frequency)
TO-220FP has no metal around mounting screw. Only metal is on back mounting surface.
TO-220FP is for application requiring that case be electrically insulated from heat-sink.
TO-220 has better thermal dissipation, but requires a plastic washer for screw when it must be insulated from heat-sink.
Power dissipation is typically one-third less with FP package compared to full metal.
But still higher power than 1969 part.