Re: [Drakelist] R4B PTO indicator...
1) Replace the lamp with a fresh one and wait for it to drift upward (that could buy you a year or many years). 2) Reduce the value of the dropping resistor and take a chance that the transistor won't break down under the extra voltage present. 3) Upgrade the transistor to a high voltage rating device and get rid of the dropping resistor entirely (permanent fix and what Drake should have done in my opinion). As a Hail Mary Pass, a fourth option may work as it did on my R-4B. Simply reverse the neon lamp leads. When a DC voltage is used on a neon lamp, only one pole is active with light. For whatever reason, going to the unused pole may cause re-establish proper firing. Mine was intermittent at normal utility voltage (125V here in my area) but I wanted to begin using CL-90 voltage dropping Thermistors to bring line voltage down to 117V from 125V. I couldn't get the neon lamp to fire at all with 117V, but simply reversing the lamp leads allowed it to fire down to 110V. I won't even begin to try and explain the chemistry and physics that made it happen but it's certainly worth a try. Paul, W9AC ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4B PTO indicator...
- Original Message - From: Don Cunningham d...@martineer.net To: Fred or Ski wb8...@frontier.com; drakelist drakelist@zerobeat.net Sent: Tuesday, September 06, 2011 8:13 PM Subject: Re: [Drakelist] R4B PTO indicator... Ski, I haven't done this, but saw a hint once that you could reverse the leads on the neon lamp and get more useful life out of it. Might be worth a try if you don't have a spare. Sometimes it's just a dirty switch contact on the transceive switch in the T4XC too. 73, Don, WB5HAK Revesing the leads is about as much work as replacing the lamp and I am not sure it works. Lamps are available cheap, a few dollars for a box of ten. Changing them requires removing the front panel, not difficult. The strike voltage goes up on old lamps and also the lamps get dimmer, old ones become blackened just like incandescant lamps. With some care you can re-use the insulating sleeving. A warning: the spacers for the panels are easy to loose. I work in a shallow box to hold any small parts that want to go flying. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4B PTO indicator...
Revesing the leads is about as much work as replacing the lamp and I am not sure it works. I swapped my neon lamp leads on the PCB, not at the panel. About a minute of easy soldering and well worth the try. Paul, W9AC ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4B PTO indicator...
Thanks, Paul, I wanted to say it was that easy, but as I said, I haven't been there so wasn't sure. It wasn't worth tearing the case off mine to see, hi. 73, Don, WB5HAK ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4B PTO indicator...
This is a fairly common problem. The strike voltage of the neon lamp tends to drift upward with age. The transistor used by Drake to switch the voltage does not have a high breakdown voltage so Drake used a resistor voltage drop to reduce the available voltage to barely enough to strike the lamp. You have three options: 1) Replace the lamp with a fresh one and wait for it to drift upward (that could buy you a year or many years). 2) Reduce the value of the dropping resistor and take a chance that the transistor won't break down under the extra voltage present. 3) Upgrade the transistor to a high voltage rating device and get rid of the dropping resistor entirely (permanent fix and what Drake should have done in my opinion). Dennis AE6C On Tue, Sep 6, 2011 at 8:01 PM, Fred or Ski wb8...@frontier.com wrote: I have an intermittant PTO indicator lamp on my R4B when using it with my T4XC. It may work all night, then sometimes it will go out and won't come on with whatever you do to switch the PTO in use. In the R4B schematic, it shows Q10 is a switch that is turned off when the transmitter is used for freq control, by a negative voltage on the INJ line to the receiver. I suspect either the transistor or the neon bulb indicator. Has anyone had this problem and what did you do to fix it. Thanks to all. 73, WB8YXI-Ski ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
Re: [Drakelist] R4B PTO indicator...
Clean adj the cable/jack for the PTO control signal on the two units. 73, Lee -Original Message- From: Fred or Ski wb8...@frontier.com To: drakelist drakelist@zerobeat.net Sent: Tue, Sep 6, 2011 11:05 pm Subject: [Drakelist] R4B PTO indicator... I have an intermittant PTO indicator lamp on my R4B when using it with my T4XC. It may work all night, then sometimes it will go out and won't come on with whatever you do to switch the PTO in use. In the R4B schematic, it shows Q10 is a switch that is turned off when the transmitter is used for freq control, by a negative voltage on the INJ line to the receiver. I suspect either the transistor or the neon bulb indicator. Has anyone had this problem and what did you do to fix it. Thanks to all. 73, WB8YXI-Ski ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist ___ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
