i have a mav. 250 tube type amp, when i key it up, it keys and then chatters and unkeys itself what could this be? :headbang
-
You can now help support WorldwideDX when you shop on Amazon at no additional cost to you! Simply follow this Shop on Amazon link first and a portion of any purchase is sent to WorldwideDX to help with site costs.
maverick 250
- Thread starter coax145
- Start date
hi, if the keying circuit is original it uses a 12aq5 tube for the relay and usually caused the trouble you are having. tx input is 3-5 watts to allow tube to operate.
I put a simple transistor keying circuit in its place using a tip 120 etc.. search rf keying cicuits, and you should find plenty of info
I put a simple transistor keying circuit in its place using a tip 120 etc.. search rf keying cicuits, and you should find plenty of info
9C1 Driver is right. do not try to repair a tube amp if you are not experienced in high voltage. there is no second chance. do not attempt any repair that I myself do to my own equipment. take it to a tech. , and have him do the conversion. the info I provided was an possible answer to your question. hope it helped.
thanks guys. i was thinking the circuit. always like to get others thoughts. oh by the way . i am well educated on those high voltages, and the effects their of. SNAP! their bite is worse than the bark. lol
hi coax145, did you get the chatter problem fixed? I've been repairing and homebrewing amps for over 20 years. check the ssb cap. and switch. the switch may seem to work, but the contact points may be fused internally. should have around 400 v rec, 200v trans. on keying tube plate. also check the input inductor if it has been over driven the inductance may not be to specs. should be around 39uh. keying tube plate voltage is from hv center tap on one of the trannys. if voltage is low, check other tranny center tap. if to specs change center tap to keying tube plate. be careful, one hand in pocket, someone else in room. 73's soretooth