Search found 6 matches

by rumblefish
Tuesday 11th Jan 2011, 3:27
Forum: CB Radio Modifications
Topic: PTBM070cox board rx improvement
Replies: 2
Views: 7829

Re: PTBM070cox board rx improvement

thank you for the reply, I have replaced all of the electrolytic capacitors. I'm in the process of replacing the smaller disc capacitors. I plan on replacing all of the transistors with new ones.I was searching online for a replacement for the 2sc710;s in this rig. there are a total of 6 2sc710 tran...
by rumblefish
Saturday 8th Jan 2011, 5:10
Forum: CB Radio Modifications
Topic: PTBM070cox board rx improvement
Replies: 2
Views: 7829

PTBM070cox board rx improvement

This is a general electric model 3-5869a 40 channel base station. the tx audio on the radio is excellent. the problem is the rx performance. the sensitivity and selectivity dont seem to be on par with most unidens or cobra radios for that matter. :banghead: Is there anything to be done internally to...
by rumblefish
Monday 30th Apr 2007, 2:25
Forum: CB Radio Modifications
Topic: cobra 139xlr
Replies: 4
Views: 7622

139xlr

thank you for the speedy reply rick!! I've replaced the 1730 with the 2999.the improvement is quite noticeable to the ear. 1-s unit receive gain on the cobras meter. fringe stations are readable now :D . now its time to replace the diodes. thanks steve.
by rumblefish
Sunday 29th Apr 2007, 22:21
Forum: CB Radio Modifications
Topic: cobra 139xlr
Replies: 4
Views: 7622

139xlr

I think tr-1 is a 2sc945. it is not replaceable with the 2sc2999. isn't tr-1 part of the noise blanker circuitry? I will replace the diodes mentioned and post results. thanks for the help rick. steve
by rumblefish
Saturday 28th Apr 2007, 5:56
Forum: CB Radio Modifications
Topic: cobra 139xlr
Replies: 4
Views: 7622

cobra 139xlr

I'm attempting to install a receive kit in this radio. upd858 chip. board number is PC-176AB. I believe that tr-5 is the rf amp to replace with the 2sc2999. I'm not sure about the noise blanker diode numbers or the am detector diode numbers that are to be changed to the 1n6263's. If somebody has the...
by rumblefish
Friday 27th Apr 2007, 2:41
Forum: CB Radio Repair and Troubleshooting
Topic: SBE power Mike
Replies: 1
Views: 4206

sbe mics

most of the sbe mics are set up for relay switching, really not worth the effort to try to re wire. best results on the cbs 1000 for a desk mike was the d104 lollipop style in the amplified form. best all around mic i have used is a handheld dm-452 echo power mic. seemed to do very well :D
steve