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Tram D201 no am reception

klj2497

klj2497

Active Member
Jan 19, 2017
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I began to check tube voltages when i touched v302 pin 2 the am receive came back to crystal and manual mode. then i traced the static down to C311 there was no static on the other side of it. C312 has static on the other side. and R308 had no static on the other side of it. it measured 99k ohm its a 100k ohm resistor. Im having a difficult time understand whats going on and what i should replace.
 

This could be from weak V-301, V-302 tubes or X-300 crystal. The crystal is right on the verge of oscillating correctly. If these parts check good, I would suspect the alignment of T-302 may be off a little.
 
I swapped out the v301, and v302 tubes and swapped out the x-300 5.8mhz cystal but no luck. im worried about tuning the T302 because it is so old ill read the alignment instuctions in the manual Im also getting a low amount of static from pin 1 when i touch it but pin 2 is the most with about 8 db of static alot more than am.
 
I think its working and you were right it was out of tune i was able to get some noise and from the speaker by tuning T300 the antenna transformer. then i tuned t300 t302 and then t301 by ear for the most static then i hooked up the signal generator and tweeked the numbers i had to switch to ac volts to get a reading thru the volt meter hooked up to the external speaker jack i was not getting a reading thru the ext speaker jack with dc volts
 
i have more static on ssb than in am is that normal or do i need to keep doing more agustments
 
If you have a copy of the manual it has the complete alignment procedure. It does not however tell how to adjust the 2 trimmer caps under the receive board as it was printed before that revision was done to the radio along with other ones that were done. If your radio is an early D201A it will not have those 2 trimmer caps. If you connect your voltmeter to the external speaker jack it needs to be set to AC volts also. Sound waves are sine waves and are measured as such.
 
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thanks Tramd i need all the help i can get i have a D201 23ch i downloaded the manual and the schematic and anything i found that has to do with the tram d201
 
I missed the fact that it was 23 channel radio. I should have read the original post better. They are still basically the same. If you have a schematic for the D201 it's probably for the VOX version. The circuit board ones are hard to come by unless you have an original. Some day I should get mine photocopied so I have a spare and also put it out on the net. The VOX version and the circuit board version of the schematics are almost the same except for the VOX circuitry. The biggest problems as you know will be old electroyltic caps and resistors. There's a hit list of those and if they are replaced along with any other bad resistors,bad tubes and an alignment done, most times the radio will be running great again.
 
i found a little flat round capacitor c714 that i get no ohm reading from. It should be 5 ohm. is this capacitor bad or am i reading it wrong
 
First of all caps aren't measured in ohms. They are measured in farads. You need a capacitance meter to accurately measure them. The "5" on that cap means that it is 5 pf and the NPO is it's temperature coefficient rating. If you measure it with an ohmmeter and get no reading that is good as caps are designed not to pass DC through them but you won't know what the cap's actual value is.
 
If you apply the test leads to a capacitor while it's still wired in the circuit, you will read the resistance of all the other circuit elements wired to that capacitor. A look at the schematic will show the other current paths that go "around" that capacitor.

For the most part, a capacitor can't be measured in the circuit without removing it. The exceptions to this rule would be the "ESR" tests done on large electrolytic capacitors. A normal DMM set to the ohms function can't do an ESR test, Equivalent Series Resistance. Takes a separate ESR meter, as a rule.

I have lost track now. What symptom does the radio have?

73
 
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Lol its contagious i had to remind myself too. I am working on three Tram d201s and its getting confusing. This is Tram #1 I was having no reception on am i adjusted the transformers and got the static to come back it is still less than the reading on ssb mode. removing the capacitor to measure it makes sense.
 
i think i found the problem i bought a set of tubes for the tram when i purchased it the box for the v302 tube said 6bk7b. But the tube inside the box was a 6bq7a. so i put the right tube 6bk7b in the radio and now it receives much better.
 
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i think the two tubes may be compatible, i checked the tubes on my tube tester they checked to be okay im still not sure what caused the receive to be weak in the first place but i think the tube was weak. I cleaned the pins and contacts with electronics cleaner, right now im really happy to be talking and hearing on this radio for the first time since i purchased it. a long time ago.
 
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