Got some time to poke at this some more. Voltage at V2 does not set up according to Sec 6.4.9 Bias and S-Meter Adj section of manual. 1. hook up meter 2. set -1.35 had to turn control all the way to get this voltage 3. S1 Adj sets 'ok' 4. Set -15 - very low like -3 Volts
Going back to the power supply I am only getting -45V at the -80V test point, (C11 and D6) after the bias diode in the power supply. So either something is bad in the few bias supply components or something in the reading is 'dragging it down' B+ is good and both sides of power transformer ohm out the same so I think the transformer is OK. Ohming out the three diodes I get a much higher 'forward' resistance on the bias diode D6. like 15k one way and 30k the other way. The two B+ diodes have a much lower forward resistance so this may be a problem. Plan now will be to unhook the 'circuit' and see if bias goes up and if not look at D6 and C11 as R141 and R96 are both within tolerance. Any other thoughts B4 I remove the little power supply board? Paul - Same result if you unplug the MUTE cable at the receiver? FAST and/or SLOW the same? Possibly bad V1, V4 or V5, unplug one at a time. Does S-Meter go up to full scale? Voltage at TP-2? 73, Garey - K4OAH Glen Allen, VA Drake 2-B, 2-C/2-NT, 4-A, 4-B, C-Line and TR-4/C Service Supplement CDs <www.k4oah.com> Paul Gerhardt wrote: > My B-line has been working but today that after hooking it back up > (was working on a TR-4) I noticed that the R-4b was not muting or > going into Standby. > > In standby or ext mute (w/o short in RCA Mute)audio is distorted > RF Gain only raises S Meter to 20 over or so. > > Something seems to have changed since I used it last a few weeks ago. > > Could this be a tube failing or ?? > > -- Paul Gerhardt K3PG http://pgerhardt.blogspot.com QRP ARCI 6674 FP 274 _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
