Search results

Hi, I picked up an old 3 tube base amp from Kris called "Power Pump". It does about 225-250 watts with 3 watts in. Does anyone have any info/manual on this amp? Can't find anything for it... Thanks. 73

Ok, need help on this! I decided to do some rebuilding/updating on parts in this amp. There are 4 big filter caps (450v/320uf) in here. I unscrewed them and removed them before I took note of the +/- alignment. 2 are chained together and the other 2 are chained together. Can someone take a...

Checks on the main board show about 15VDC in RX. With full modulation on SSB drops to 13.8-14.

Well like I said before, all the suggestions on here are all good and worth investigating. As far as the PS in this radio goes, should not be an issue. I rebuilt it myself several months ago with beefed up parts. Actually had a bit to much coming off the board and had to scale it back. And...

Ok, thanks. I have an old Kris Power Pump that does about 250 peak so I don't think an extra 50 is gonna entice me to buy!

Hi, Does anyone have any info on a Thunderbolt 305 base amp? How many watts do they do and what is tube configuration if known...? Thanks!

Hi-yes the shield is there on the freq counter box. I tried moving the amp further away but that did not change it. I had to order some toroid cores so I will have to wait on that. What concerns me is that I had the amp for almost a year with everything in the same spot and essentially unchanged...

Also, what do you mean by better RF bypassing? Thanks!

I lot of different ideas on this thread, all are speculation. I will try the chokes and spacing issue first since those are the "easy fixes"...thanks for the feedback.

Hi-thanks for the info. It is a PAL 750B base amp. Uses 9, 8950 tubes-I believe 1 drives 2&3 and they drive 4-9. . About 800 watts out on high with 2 watts in. I will try the coax lengths and see if that helps...

Ok, that also sounds like a viable reason though I do not have another radio to confirm with. Let's assume it is, what would be the cause of the high SWR between the amp and radio and the wattage loss caused by having the amp in line even if turned off?

UPDATE: The input SWR (between the radio and Amp) IS high-around 2.5 that includes with the amp turned off. I changed the jumpers but that made no difference. SWR between amp and antenna is normal--1.3 or so. Perhaps then this is the issue? Not sure what would be causing that though. Perhaps...

I agree...! Any ideas on how to diagnose/stop that? Again, it was never an issue until recently...

Jeff, I will check that. One thing I notice is that the output from the amp when it is totally turned off is about 1/2 of what is going into it from the radio. Another words, I use a about a 2 watt carrier out of the radio and into the amp. If I check the wattage after the amp, it is down to 1...

LSB mainly...

The problem does NOT occur in the radio with the amp off or in stand by, only when it is kicked in. The radio works fine otherwise. The amp and radio are on separate circuits as well. I am leaning towards some kind of RF leak via some kind of defective part in the amp or bad jumper, ground, etc...

Jeff, Nothing has changed in terms of equipment or otherwise. This problem started without any apparent reason in recent weeks. I will try to move things around a bit and try to eliminate or confirm that any external parts (coax jumpers Low pass filters, grounds,etc) are causing the issue and...

Jeff, All those sound legit. The radio and amp are on different circuits so I dont think it is that. I also thought RF into the radio but why only the problem on SSB and not AM? How would I fix that even if so? the amp and radio are very close together. Maybe separate them more? I will check...

CLARIFICATION: The amp is not drifting. It is the radio that is drifting. The amp seems to be causing my radio to shift off frequency while TX'ing on SSB. the Cobra 2000 has a built in freq counter which is obviously behind the amp. That is what is changing on TX with the amp.

Hi, the radio is fine without the amp in use-no problem at all. the radio is a cobra 2000. I know, does not make much sense at all...