Re: [drakelist] T-4XB Troubles
[EMAIL PROTECTED] made an utterence to the drakelist gang -- On Tue, 30 Nov 2004 [EMAIL PROTECTED] wrote: while I'm at it. Does anyone have a good Internet source for them? Also, does anyone have a good source for high value, high voltage electrolytics such as the 125 mfd. 400 volt contained in this supply? Once again, thanks for all the great information. I am happy I found this list! http://www.harbachelectronics.com/reference/harpg4cart.htm RK-AC4 - complete kit for replacing the guts of the AC-4 supply. 73 Jason N1SU -- On Behalf of [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] T-4XB Troubles
[EMAIL PROTECTED] made an utterence to the drakelist gang -- Hello all, Someone gave me a x-tal set (x-tals and labels) for the SPR-4 receiver. He thought it was usefull for my R4C, but it is not of course. Is there anyone out there who I can make happy with these x-tals? I only need shippingcosts payed. Best 73, Dick/PA2DW -- On Behalf of [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] T-4XB troubles
Greg, Considering how old your T-4XB might be and some of your problems are ones I had, your filter capacitors in the AC-4 powere suipply may have dried up and need replacing. This affects the bias and there could be ylour problem. There are others on this list who can give you more detailed direction. I wouldn't trying to do any more with the rig until you ascertain this is the problem and get it repaired. This will save your finals. Bill Ellis, WB9CAC[EMAIL PROTECTED] - Original Message - From: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, November 30, 2004 1:31 PM Subject: [drakelist] T-4XB troubles Hey all, I am new to the group, and would like to start off by picking the collective brain :-)) I am having trouble with my T-4XB. I was working CW with it the other day when all of a sudden, it shot a fuse. I changed out the fuse and started it back up. The new fuse didn't blow, but when the set warms up, and the tubes start to conduct, the TX/RX relay kicks in and the plate meter starts to show a lot of plate current, around .25 to .3 on the meter. The transmitter won't tune, won't key, won't do anything except light up. I did a visual check underneath, and nothing is obviously burned. or out of place. I thought it may be the 6EV7 tube associated with the relay, but I have no way of testing the one in the set, or any of the others I got with it. Anyway, I thought this may be a common problem associated with this particular set and decided to put the problem in front of the all knowing ones of the famous Drake list! Anybody got any ideas? 73's Greg Gifford / KG4MMY
Re: [drakelist] T-4XB troubles
[EMAIL PROTECTED] made an utterence to the drakelist gang -- Hi there, The 6EV7 is sort of a known trouble spot in the T-4XB when it comes to the the relay turning on when you do not want it to. But I think this may be something different since you are seeing the plate currents that you state. I think you might have a problem with a filter capacitor in the negative bias suply of your AC-4 (or AC-3). If that filter opens up and is not doing a good job of filtering, the ripple that will be on the bias supply can be rectified by D10 and then passed to the grid (pin 7) of the 6EV7 and turn on the relay. Also, lack of filtering will lower this negative bias voltage and result in increased plate current in the finals from lack of bias. If the filter capacitor in the supply goes short you will lose bias and have improper final amp current, but I do not think you will have the relay turning on that way, unless there is something I am failing to remember, which could easily be the case. Measure the bias voltage under load (meaning from within the T-4XB) and see if it is low. You ought to be able to set it all the way to -70V or so with the pot on the AC-4. If you have an oscilloscope you could look at the ripple voltage. It should be pretty low. If you see 10 volts of ripple, replace the filter cap. If you need a capacitor for that bias filter I can give you one to get it running. Let me know if I was right. If not, ... anyone else want to take a crack at it? Michael Smith N0XY [EMAIL PROTECTED] wrote on 11/30/2004 01:31:49 PM: Hey all, I am new to the group, and would like to start off by picking the collective brain :-)) I am having trouble with my T-4XB. I was working CW with it the other day when all of a sudden, it shot a fuse. I changed out the fuse and started it back up. The new fuse didn't blow, but when the set warms up, and the tubes start to conduct, the TX/RX relay kicks in and the plate meter starts to show a lot of plate current, around .25 to .3 on the meter. The transmitter won't tune, won't key, won't do anything except light up. I did a visual check underneath, and nothing is obviously burned. or out of place. I thought it may be the 6EV7 tube associated with the relay, but I have no way of testing the one in the set, or any of the others I got with it. Anyway, I thought this may be a common problem associated with this particular set and decided to put the problem in front of the all knowing ones of the famous Drake list! Anybody got any ideas? 73's Greg Gifford / KG4MMY -- On Behalf of [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] T-4XB troubles
Greg, Check the negative bias supply in the AC-4...sounds like you may have lost it. 73, Gary
[drakelist] T-4XB Troubles
Hey all, Well, the list came through for me on this one big time! Many thanks to Garey, Bill, Gary and Michael for all the great info. The concessus was that I should check the electrolytics in the bias supply, which I promptly did, and found an open 40mfd . I have ordered the proper replacements, and should be back in business in a few days! It was also suggested that I replace the diodes while I'm at it. Does anyone have a good Internet source for them? Also, does anyone have a good source for high value, high voltage electrolytics such as the 125 mfd. 400 volt contained in this supply? Once again, thanks for all the great information. I am happy I found this list! 73's Greg Gifford / KG4MMY
Re: [drakelist] T-4XB Troubles
Michael N0XY [EMAIL PROTECTED] made an utterence to the drakelist gang -- Once again, thanks for all the great information. I am happy I found this list! 73's Greg Gifford / KG4MMY Ah... did anyone tell him that we all want money for this? heheh JK Michael 73 -- On Behalf of Michael N0XY [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
Re: [drakelist] T-4XB Troubles
Garey Barrell [EMAIL PROTECTED] made an utterence to the drakelist gang -- Greg - You might want to look at http://www.theheathkitshop.com/hp23r.html He offers a slightly different board made for the AC-4. The Twist-Lok style of capacitor such as used on the AC-4 is all but extinct these days. Here you have new PC style mounting capacitors, new diodes and resistors. The only other option is to install axial (wire lead) capacitors under the chassis of the AC-4. Axial and PC mount capacitors are available reasonably from Mouser and other distributors. 73, Garey - K4OAH Atlanta [EMAIL PROTECTED] wrote: *Hey all, Well, the list came through for me on this one big time! Many thanks to Garey, Bill, Gary and Michael for all the great info. The concessus was that I should check the electrolytics in the bias supply, which I promptly did, and found an open 40mfd . I have ordered the proper replacements, and should be back in business in a few days! It was also suggested that I replace the diodes while I'm at it. Does anyone have a good Internet source for them? Also, does anyone have a good source for high value, high voltage electrolytics such as the 125 mfd. 400 volt contained in this supply? Once again, thanks for all the great information. I am happy I found this list! 73's Greg Gifford / KG4MMY* -- On Behalf of Garey Barrell [EMAIL PROTECTED] Submissions:[EMAIL PROTECTED] Unsubscribe:[EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost:[EMAIL PROTECTED] - help in body of message Zerobeat Web Page: http://www.zerobeat.net Brought to you courtesy of TLCHost.net http://www.tlchost.net/ --
