hi there Anthony I have put a LOT of time in on those rigs. First, the culprit putting the AC on the chassis is not going to be your Filter caps, THOUGH if your hearing hum on your audio, they need to be replaced.
Check all of those damned ceramic disks that go fromthe A/C input to the chassis. These are usually around some small copper inductors. I don't have my manual so I can't tell you what the schematic designation is. Your Modulation current pegging will be another problem I'm afraid. Maybe not. Check those mod tubes real good. I have some other suggestions, while you have it out of the case. If your interested. Ronnie On Tue, 23 Sep 2003 20:05:06 -0400, Anthony W. DePrato wrote > Well after setting for over a year . i wanted to fire the valiant up > last weekend.. everything went great till i keyed the relay.. > HUMMMMMMM. man do not remember that hum in the 75A2 last time i > keyed the transmitter.. switch the meter to MOD keyed transmitter > PEG...... fuse blows... OK... put in another fuse fire it up ok key > dowkey antenna relay HUMMMM... this is not right hi hi.... start > undoing antenna . SPARK SPARK.. bad sign... got the old 260 out > have 60 volts a.c. to ground.. well no wonder it hummmed hi.. > hi.. now to find some 15 mfd 450v caps jezzz why not just recap the > whole transmitter while i have it on the bench... do the Audio mod > also... my question where was the audio mod found ? have to get the > old AES book out tomorrow and order the caps.. guess i should just > recap the Thunderbolt while i am at it.. what is a good place to > find HV caps ? fired up the HT 37 SX 115 on 40mts . and worked a few > stations running 20 watts high power AM hi hi.. Thanks for any help > 73 Tony wa4jqs > > Anthony W. DePrato WA4JQS > Since 1962 > WA4JQS / VP8BZL / VP8SSI / 3Y0PI > CQ DX Hall Of Fame # 35 > > _______________________________________________ > AMRadio mailing list > AMRadio@mailman.qth.net > http://mailman.qth.net/mailman/listinfo/amradio The "AM" voice of Shreveport, Louisiana USA formerly WN5AIA and WB5AIA I got my Extra Class the old fashioned way... I earned it!
