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I have a 148GTL that receives low on AM only. SSB reads fine. When I inject a S-9 signal into the antenna jack the radio's s-meter reads 9 s-units on SSB. When it is injected on the AM side it reads about 1.5 s-units. All the cans in the rx chain seem to peak ok and none of the slugs are...

I have a Cobra 29 LX LE that transmits fine. It has great modulation. PA works just fine. I have NO signal on the digital S meter and no audio coming thru the internal or external speaker. Not a mic issue. I can hook a signal generator to the antenna jack and hear no audio or signal. I have...

EPT360015C board this was on during a storm and may have been zapped. Here is what's happening. The radio turns on and as soon as it does the signal meter pegs out. It does Transmit full power and the tx/rx LED does toggle. The radio has great modulation as well. But it ONLY transmits on...

Picked up this unit at a garage sale for 7 dollars. It has no tx and would like to get it going because it is in excellent physical condition and has a very low serial number #60. When you key the mic, nothing happens. The green rx light stays illuminated and does not toggle to red or go out. I...

Weird problem with this one. I used my audio probe and traced back to where I lost my modulation. I have modulation coming up to and out of TR44 (2sc2166) collector going into the junction of C209 (820pf) and C338 (390pf) but that is where it stops. It is not getting to the input (base) of the...

I just picked up one of these with the 2290 final and was looking to re-align the radio. Does anyone have a service manual for this model. Thanks. -75

Picked up one of these modulators. The relay works when I key the radio into it but I get absolutely no power output. I have tried 2 to 4 watts input drive to the amp The receive pre-amp button works and amplifies the receive, so the transistor is ok. ..just no power out. The variable pot on...

I had this amp given to me for some work I performed. I wouldn't mind re-doing this amp but I cannot find any info on the net about it. I would like to know what tubes it uses, It only had one tube in it when I got it. Thanks.

I have a Cobra 29 LX made in China. The radio worked fine. I keyed it up and unkeyed it about 4 times in a row into a dummy load and it just stopped transmitting after that. Receive works fine. The PA works fine. The radio does go into tx mode on the display but has no RF output or modulation. I...

Has anybody tried replacing the stock IRF520's with the ERF2030+ in the 2970N2 PA section ?? They are advertised to be a direct "drop in replacement" but with more power. Just curious. Here is the quote: Replaces Finals & Driver Transistors in Cobra, Uniden, All DX Mobile Radios, Galaxy...

Maybe someone who knows these boards really well can shed some light. It's an early run Madison with the D858 PLL. Pulled this one out of the mothballs. Because it is in mint shape, I decided to put in new electrolytic capacitors (yes the problem was there before I recapped it). It receives...

I got this radio in on a trade without the side car speaker. The previous owner said it worked fine. It had output in all modes on the wattmeter so I took it in on trade. It wasn't until I got back home and hooked a speaker in the back that I noticed this problem because the wattmeter did show...

Hi. I just got a Cobra 2000 GTL in from a buddy for alignment. He had re-capped the radio himself, so all electrolytics are new. Everything aligned up ok until I got to adjusting L38 for balance power between ch1 and ch40. L38 coil will adjust but the carrier is not even between ch1 and ch40...

This radio transmits good in both modes. When I have the S/RF CAL SWR switch in the S/RF position the meter instantly jumps up to about a S-9 reading. It doesn't do that in the other 2 positions. The meter movement is ok. I have replaced the switch (it was nasty) ... D73, D79, D46, D45 were...

I'm a little confused on 7.8000 MHz entering the mixer IC5. Especially as it goes thru the coil before it enters the mixer. Reference schematics do not look correct to me. Here is Rick Jackson's re-draw of the Cobra 148GTL. He has the 7.8000 MHz entering IC5 on pins 11 and 13 (where the 34.XXX...

Well, this was a joke. I don't know who wrote the alignment procedure for this model radio but I thought I would share my frustration of wasting a few hours. The procedure says (TP3) output tx mode.... attach your scope to the junction of R6 and JP14 junction and adjust L16 on the scope for...

I picked up a Galaxy Pluto for free due to it not working. It was DOA. I replaced the regulator (TR51) with a 2SB817 and replaced TR50 with a TIP42C. The radio then came to life when I turned it on...but was in TX mode without keying the mic. Now, I have read that a faulty 4558D (dual op amp IC)...

OK... Has anybody ever experienced something like this??? I key the mic in AM mode. The carrier starts at 2w and rises to about 5w and then goes back down to just over 4w where it remains stable. I key it right back up and it does it all over again. SSB is fine for output (about 15w PEP) All...

I purchased this Cobra 2000 GTL on eBay as a parts radio. I know...I know...lol. It is made in Taiwan and the board number is PC-497AB. Initially the radio would only transmit very low on both AM and SSB. That is how it arrived. The radio has since been totally re-capped, electrolytic, ceramic...

I purchased a SHOCKWAVE 5/8 ground plane antenna and put it up on the tower (50' up). I'm using Times Microwave LMR-400 coax (100') to run to the shack. I tuned the antenna for use on 27.385MHz as I ONLY talk on CH38 LSB) using a AA-230 ZOOM RigExpert antenna analyzer. The SWR was 1.06:1 on...