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UGH!!!! I need to get my head above water!!! That's better than saying I need to remove it from.......
So, I think that schematic is wrong by labeling VR10 in that location. In the alignment guide VR10 is for TX Meter. On that schematic the TX meter adjustment is labeled VR9. I should have...
As an update, I broke out the trusty Knight VTVM and measured the input to VR10 (TX meter adjustment) to compare it to the wattage output of the radio. On an AM carrier I read 4.2vdc at VR10 and the voltage dropped to 3.3vdc over 15 seconds while the carrier remained steady. While I do not...
So I have a Cobra 25 LTD Classic side mic (old school) and I am looking at some pics of the 21. The 25 has a few things that the 21's do not such as a NB, RF Gain and CH9 switch and I am not seeing a 21 with them. The 21's have a variety of things like a Loc/Dist switch, Dimmer knob, and even...
Hi Everyone,
I have an op with a 2950DX and mostly uses it on AM. When he 1st keys up the meter will display 4 bars and display 3-4 bars of red on modulation. After about 30 seconds of use (not continuous) the meter will no longer show modulation. It wil contiinue to show the carrier power...
I'm going to look at this tomoorow but you know.... I am using the alignment guide for that version 148 and I noticed that the alignment guide for the more recent (China) versions have you align the oscillator on 19.
Good Day Men,
I have a 148 from Malaysia (1992) on the bench for aligment. I have removed the glue and I will say, this one had more corrosion than I am used to. I had to replace a few resistors, caps and 1 diode becasue they were so corroded. The radio was way off frequency when I started...
So here is the update for now. The attenuator is bad. The relays act a lot like a solenoid and one of them is bad. I did order a replacement off eBay and it should be here this weekend. We shall see. These HP higher end generators are built like a spaceship. Holy smokes is it impressive......
Ok, so the life of a hobbiest. I am aligning a radio and having trouble with the receive alignment. I play with everything but it turns out that my HP 8660C signal generator is not working correctly. When I go from -80dB to -70dB the signal drops out. It's a battleship of a piece of...
A little update here. I had a few minutes today at the bench. Also, see attached for a better schematic that shows this circuit and a pic of the board.
When in TX mode I get 65mA at the meter (about 1/2 way). Based on the schematic, should I get a similar reading at D5 or at D316? I will...
Hi Everyone,
I hope you all are safe as these storms blow through!!
I have a Cobra 29LTD Classic, 4-pin side mic, PC-900 board) in for alignment and everything works except the meter shows nothing on RX. The RX did align fine (-12db sinad @ -113db). The RF Gain knob and alignment adjustment...
Good Day Everyone,
I picked up a Pride 150 in great condition (inside pic attached). I tried it out on air and a local op siad it sounds great on AM but bad on SSB. His comment was that it sounds like it's not biased correctly. There are 2 varicaps on the inside and I am wondering if it may...
Ok, so I had this same issue with my 30 amp supply. It's a TP30SWII. It was only powering a 150 watt amp and it did not do this at 1st. Something internally became loose, not broken though. I am anticipating that it is the transformer or an inductive coil as there are no moving parts except...
I think at this point I am going to pull all of the parts in this area and test them. I will replace all of the easy ones like resistors and caps. I'll even throw the 612 from the 2950 in it. Then I'll test it out. One other thought. This is the radio that had a broken L3 inductor for...
Well, it's fixed..kind of :) Tramd was correct that the USB crystal was the issue. I was able to use a known good crystal and the radio aligned perfectly. Now, for the final repair, I need a 11.2858 crystal as the good one went back in my radio.
Thanks so much Tramd!!!
Very interesting!!!! So it is possible that because the USB crystal is bad that is causing the AM TX issues? I will swap in a good USB crystal and try that. Actually, based on some memories of alignment proceedures referencing USB and AM together that makes sense. Not that I understand how...
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