Any advice appreciated guys.
Can a 2SC2290 transistor be replaced with a 2SC2879???
I looked at the data sheets for both & the voltages are all identical between Collector/Emitter/Base.
The only difference I can see is the collector current is higher (5A more) on the 2879 (the 2290 is 20A) & the input power is higher on the 2879 (can take 10w PEP)
Will I need to upgrade the driver & re-align the TX coils???
The radio is the Cobra 200 GTL DX (Rev 3)
Many thanks.
PA transistor swap - advice needed.
PA transistor swap - advice needed.
You're 5 & 9 - what's your QRZ again???
- speedracer6g
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I was looking at the data sheets for the two transistors. The only Difference i see is the collector output capacitance is about 200pf higher wich isnt a big obstacle i would think, however the higher drive that it requires is a different story. You may want to look into upgrading the driver to a mosfet like the irf520. You may be able to get the extra drive you need just from that. I would think it would be possible because the mosfets have a higher gain and you should be able to squeaze 10 watts drive pretty easy out of it. I will look into it myself because that would make a nice upgrade to go from 60 pep to 100pep. The only other problem may be heat.
Mike
MIKE
Mike
MIKE
- speedracer6g
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It's the RD16HHF1 Mike & whilst the drive is lower than that needed to get full output from the 2879, the IMD figures are lower & I'd guess they'd run cooler not being driven hard - that's the logic of the swap, not the higher output (but if I get more as a by-product then it's a bonus!)
ATB
Steve
ATB
Steve
Last edited by Animal on Sunday 1st Jun 2008, 6:05, edited 1 time in total.
You're 5 & 9 - what's your QRZ again???
They can be swapped but the resistor/capacitor feedback between the collector and emitter usually need to be changed to allow for a somewhat greater feedback, or the 2sc2879 can self oscillate. I dont have the exact values for the resistor and cap handy, but I will see if I can give you a recommendation later.
Re: PA transistor swap - advice needed.
Try and stay with 2290 as 2879 will be more trouble they it is worth.
Rick.