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Tram D201 ssb very low receive

klj2497

klj2497

Active Member
Jan 19, 2017
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I have just purchased a refurbished Tram D201. I decided to attached a siltronix vfo by removing the 16.5585 crystal i Did the modification right but when was putting it back together i got a phone call That distracted me. well when i transmitted i realized i had not plugged the internal cables to the synthesizer board. When i looked in the cable terminal was in the middle of the receiver board. When i put the mode switch in side band i did not get any reception, but the transmit is fine on all channels. am reception is fine. The vfo worked great. Then i decided to undo what i had done to be sure that was not the cause after putting the 16.5585 crystal back in, No changes, the ssb upper and lower still has very low reception I am very upset with myself
 

I checked tube voltages. v502 pin 3 should be 40 volts. it measured negative voltage. I traced back to r520 and on the other side of r520 the voltage is back to 230v is this resistor bad?
 
It worked. The R520 was the receive problem on ssb. I was pushing the old resistor thru the hole in the trace, when i lifted the iron the trace stuck to my soldering iron and lifted from the board. it gave me a heart attack. I was able to coax everthing back in place and soldered the resistor in .
 
Use a piece of solid buss wire and bridge that trace . Also if you just replace all the 1 watt and 2 watt carbon comps right from the start with 3 watt that most likely will cure most problems. Then replace all the electrolytic capacitors. Or at least all the high voltage ones.
 
Thanks KneeBiter it looks like most of the resistors and capacitors have been replaced. but I noticed that the R426 resistor is red-red-brown-gold 220 ohm. 1/2w .from looking at my other trams and The schematic it should be a 220k ohm 1/4w. red-red-yellow-gold . would that 220 ohm even work in there.
 
Those traces get really fragile. Got in the habit of leaving the resistor lead long, folding it down along the foil trace and lap-soldering it to the nearest next solder pad along that trace. Makes the part more secure above the pc board.

73
 
Thanks for the great idea nomadradio. The output is a little low on this refurbished tram so I checked the bias. it was set really low -.43v and -.47vam the bias was turned almost all the way down. The output was a little less than 4watts am and about 10 watts lsb. The usb was swinging over 12 watts though. I set the bias to -24vam and -32vlsb. and adjusted t700 for max dc and the am wattage dropped to 3 1/2 watts am, and 8 watts lsb The usb stayed about the same. now I am really confused. what should i do next.
 
Another unusual thing is that D11 and r7 was switched.so i put them back in their spots.
 
I adjusted t700 and c706 again. and was able to get almost 4watts am and a good 10w lsb. usb, swings about 14watts. readjusting the alc downward helped. i use a linear and when the tram in place of my cobra 148gtl. hooked up as a base. The linear will not stay keyed on ssb when i speak, it looks like the modulation falls too low. below 2 watts ,but the 148gtl modulation stays up longer, and doesnt have that problem.
 
No, it has three 6jg6a its the Demon 250 i replaced the two big caps, and some resistors. im going to order the smaller can shaped capacitors next.
 

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