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it is late but it is twards the back of the radio between the two tuning cans tr7 think i beleive it is a 1764. dont quote me on that. i would replace with a 2sc2999 if you can get it. i will double check later to confirm this. MIke

wondering what is the best tube tester to get or most poplular for working on radio equipment. want ot make an investment for my shop and dont want to waist my money on one that wont do the job. Thx, Mike:biggrin:

4.7k resistor change. just found out that you will want to change the 4.7k oum to a 10k pot. you will want to set the Vgs voltage to about 2.7 to 3.0 max. if you do the 4.7k it runs between 3.2 and 3.6 and the final runs too hot. i blew a couple erf2030s the other way and now it seems to...

what driver are you using to run the irf520? i have some irf540 here i was giong to mess with. and since the mosfet likes volting can it be done on the cobra 25 and 29. call me dumb but i here about this volting stuff what exactly is volting and how is it done?

Hey guys i just wanted to chime in here i would recomend not jumpering d8 it can cause your radio alot of problems. if you remove the antispiking diode it can blow out you audio chip and fry your mod transformer. i have seen it too many times. besides i get just as good of results without...

Yep i used to jump the diodes until i found out what happens and it realy dosnt get you much. i had this radio laying around and got the transmit side to work but the receiver dosnt open up until u start pumping about 81uv into the receiver. on the brite side i got the new ERF2030 mod working...

I am working on a Cobra 25 nw st. It had carrier with no tx modulation and no rx. i traced the transmit problem to a burnt d10 diode and burnt modulation transformer. i replaced both items plus the audio chip. no transmit works fine but i have very poor rx i have to turn my monitor up to 85...

did you check youe modulation transformer i have had one fry and caused an audio problem. mine was caused by someone soldering a jumper on D10 and caused the radio to self distruct. it blew out the audio chip and it wouldnt rx that well. just a thought. you can usaully tell because the...