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Post by spitfire441 on Oct 28, 2008 9:47:13 GMT -5
Hey all, I just aquired a real nice 40 ch tuber. Problem is lack of documentation and no power cord. I understand that this radio is the same chassis as the Robyn 240D and the Teaberry "T" as well as the Gemtronix GTX 5000,Colt Midnight Special and not far off from the lafayette Comstat 23b.
I have two questions maybe some can help.
1) I need the octal power plug pin out. It is NOT the same configureation as the listed radios. I just want to be sure I do this right the first time!
2)Also any one know the audio tube? The #'s have rubbed off and all I can see is the last 2 digits of an industrial tube # Visible is, its either ??39 or ??89. I know it is not a 6BQ5 or equiv. It is also not a 6AQ5 or equiv.
Thanks in advance.
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Post by Junior on Oct 28, 2008 13:29:03 GMT -5
I just asked the same question about the octal plug pinout. I have the same radio and want to get her going. Tell me what position the tube your asking about and I will look at mine and see if I can read the number for you.
PR
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Post by spitfire441 on Oct 28, 2008 14:53:32 GMT -5
Looking at the front of the radio behind the speaker, it is the one to the far right and front. Tall tube,next to the 12ax7. Thanks.
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Post by Junior on Oct 28, 2008 17:16:33 GMT -5
6bq5 / el84.
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Post by spitfire441 on Oct 28, 2008 18:08:15 GMT -5
Thanks! I am begining to belive it is the wrong tube there. Audio modulator tube 6BQ5 is very common. All of the radios I previously listed with the same chassis, use a 6BQ5. I put my tube in my tube tester and set it for 6bq5 and it didn't match. I'll see what happens when I figure out the power plug. If it has weak or bad audio I'll put in a 6BQ5 there. |
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Post by Junior on Oct 28, 2008 21:07:04 GMT -5
Hey, no problem. Now if we can find how to wire the power cords....
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Post by spitfire441 on Oct 29, 2008 4:32:19 GMT -5
I find out or figure it out. One way or the other.
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Sandbagger
Administrator/The Boss 
Posts: 6,247 
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Post by Sandbagger on Oct 29, 2008 6:53:40 GMT -5
I find out or figure it out. One way or the other. Check your E-Mail. That radio matches the Comstat 25B the closest. Even the pin numbers appear to be the same. |
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Post by spitfire441 on Oct 30, 2008 4:16:34 GMT -5
The power plug pinout for the Shakespere 740 is, pin 2 and 3 are for 120VAC. Jumper pins 4 and 5. Thats it fo AC operation.
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Post by Junior on Oct 30, 2008 13:11:32 GMT -5
Much Appreciated. I wired it up today, and the old girl works!!!!! Great receive, keys 2-3 watts but low modulation. I will have to check the tubes.
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Post by spitfire441 on Oct 31, 2008 6:36:28 GMT -5
I got mine fired up and works like a champ. 3 watts with forward swing. Ran it for about 3 hours last night. The locals like it. It has that nice warm tube radio sound.
Funny looking at a 40 ch LED display on a tube radio.
Check the modulation pot inside the radio, full CCW is max mod. It is the pot on the chassis by the 12ax7
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Post by Junior on Oct 31, 2008 7:18:19 GMT -5
Cool, Two more classics saved from disaster. I will check the audio pot, but now I am wondering if the mic is wired correctly. It is wired like the cobra 4 pin plug, keys fine and receives great,( great ears). But as I said, no audio out at all? Can you check yours and let me know? I know what you mean about the 40 channel display, kinda strange, isnt it. If I can get it working right, I will have another cool radio to have to choose from. Decisions, decisions ;D JS  |
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Oct 31, 2008 12:22:24 GMT -5
I got mine fired up and works like a champ. 3 watts with forward swing. Ran it for about 3 hours last night. The locals like it. It has that nice warm tube radio sound. Funny looking at a 40 ch LED display on a tube radio. Check the modulation pot inside the radio, full CCW is max mod. It is the pot on the chassis by the 12ax7 What was the problem with the weak receive audio? Weak tube? |
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Post by Junior on Oct 31, 2008 15:21:24 GMT -5
Got it!!! Had a time finding a mic that the radio liked, but wired a Galaxy hand mic to it and it accepted the transplant. Keying 4 watts and swing to 6 watts with modulation, and great ears, too. ;D
Thanks for all of the help guys. It is appreciated!
JS
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Sandbagger
Administrator/The Boss
Posts: 6,247
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Post by Sandbagger on Oct 31, 2008 19:22:55 GMT -5
Got it!!! Had a time finding a mic that the radio liked, but wired a Galaxy hand mic to it and it accepted the transplant. Keying 4 watts and swing to 6 watts with modulation, and great ears, too. ;D Thanks for all of the help guys. It is appreciated! JS That's what this forum is all about...... |
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Deleted
Deleted Member
Posts: 0
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Post by Deleted on Oct 31, 2008 21:18:25 GMT -5
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Post by Junior on Nov 1, 2008 7:53:38 GMT -5
Here ya go. Hope this works.
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Post by spitfire441 on Nov 2, 2008 5:30:51 GMT -5
I'll take a pic today and upload...... I have been using mine regularly now. I have a leaky cap somewhere in the final? section that is laying down I need to find. Power and modulation drop off and go wacky after about 4+ hours of use. Turn it off wait 10 miniutes, good for another 4hour. I need to find THAT problem. Otherwise it is a good rig. Great "ears" and good warm tube audio. The locals like it, and most of them are of the Connex crowd.
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Post by Junior on Nov 2, 2008 7:54:09 GMT -5
I too have been using my 740 regularly, and have found that after a few hours of running the receive audio drops off pretty good and I think the meter activity follows suit. The receive sems good, but I have too keep turning up the af gain until I end up at the top end of the control. Any ideas of which tube to check first? I sure wish I had a schematic.  |
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Post by spitfire441 on Nov 2, 2008 16:58:10 GMT -5
I have my Shakespere on now!. Take a look at the Robyn 240d, Gemtronics GTX 5000, Lafayette Comstat 25B, Teaberry "T", they all have very similar chassis. The schematics for those should help out.
Your problem might be in the reciever section, as your S meter is tracking the reduction in audio.. Just a guess, but I would check there.
I guess I don't need post a pic as you already did.
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Post by spitfire441 on Nov 2, 2008 17:16:08 GMT -5
 Ah well, I had to  |
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Post by Junior on Nov 2, 2008 19:16:16 GMT -5
Yeah, but yours is nicer.  What mic are you using? |
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Post by spitfire441 on Nov 3, 2008 5:41:57 GMT -5
Yeah, but yours is nicer. What mic are you using? The old standby, D104. |
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Post by 238 on Nov 3, 2008 19:06:06 GMT -5
 Here is a pic of mine. 238 |
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What mic are you using?