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Post by chester on Jan 2, 2011 17:15:40 GMT -5
Hi everyone, I recently started using this radio after it had been setting for a long time. The receiver seems to function ok, and at first the transmitter worked well , but after several days I have lost transmitting, you can hear the relay click in the box and the needle now pegs when speaking ( it was only swinging up to about 2 1/2 on AM) yet I can't be heard. I do have a new power tube coming for the transmitter. Could any of you give me an idea what to check first. I did check and set the Bias on the transmit power tube as per owners manual. I sure would appreciate any input. Thanks
Chester 221
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Post by gator7 on Jan 2, 2011 20:29:34 GMT -5
Check all of the tubes 1st. You may have lost a power resister? Also a few caps may have gone south.  If you can't fix it. Send it to Alan, Fixer on this forum. He worked on my MK III. Great job.  Good luck. |
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Post by chester on Jan 2, 2011 20:39:54 GMT -5
gator7, thanks for the reply. all tubes illuminate, and I do have a new power tube coming, I can check resistors , although I sure wish there was a component location photo. I have worked on tube guitar amps.
Chester 221
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Post by Sniper..Unit 305 on Jan 3, 2011 8:53:04 GMT -5
gator7, thanks for the reply. all tubes illuminate, and I do have a new power tube coming, I can check resistors , although I sure wish there was a component location photo. I have worked on tube guitar amps. Chester 221 Try this link Chester, it should give you all the info you need. Sniper cbtricks.com/radios/browning/golden_eagle_mark_3/index.htm |
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Sandbagger
Administrator/The Boss 
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Post by Sandbagger on Jan 3, 2011 11:54:47 GMT -5
Well, I can't really give you an "ah-HA" part to check, but looking at it logically, there are three things that cause the most problems for aging tube rigs. One, obviously, is a weakening tube. They are reasonably easy to check. The next thing that goes bad are electrolytic caps. But since they are mostly seen in the power supply section, you will usually hear an increasing A.C. hum as they start to wear out. The other thing are the crystals. Crystals drift frequency with age and can fail completely. You should check all of your channels to see if the problem is only there on a couple or on all of them.
Since you also mentioned that the modulation meter is pegging, that may also be a sign of a mode switch breakdown. When those get old and filled up with years of crud, a resistance begins to form between contacts. Once current starts to flow, it will burn a carbon trace into the wafers of the switch, which will conduct even more current from the high voltage section to the lower voltage part. If you catch it early, you can clean the swtich and scrape any surface carbon coating away and you may be good to go for a while.
On the other hand, if the meter is simply pegging on voice peaks and not slamming hard against the stop, that may simply be an indication of the RF final output tube not loading down the modulator, which then allows the meter to swing harder.
It's really hard to accurately diagnose problems this way, but I would start with a checking of the tubes and also make sure your swiutch contacts on the channel selector and mode switch are clean. Sometimes crystals on some channels will become intermittent if the switch is dirty.
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Post by chester on Jan 3, 2011 13:35:52 GMT -5
Sandbagger, thanks for that detailed reply, it gives me a lot to consider,upon a check on the under chassis, I see a 10K resistor on the power cap(big silver one) that looks burnt, now I am going to unsolder this and check it for an open, I'll keep you posted. Thank you!
Chester 221
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Post by gator7 on Jan 4, 2011 22:59:42 GMT -5
Well I was close in my diagnosis. But like they say, that only counts in grenades.
Thanks Sand bagger.
Good luck Chester.
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Post by chester on Jan 5, 2011 23:48:42 GMT -5
Just an update, and thanks for the input fellas, I replaced the 7558 transmitter tube and cleaned and re-tensioned the tube sockets and bingo I am now transmitting, I have a very low dead key , around 1 watt and no swing at all. Had my son talk on it as I took off in my mobile, the audio and modulation is really superb, but not much of a carrier if that makes sense. I'm up and running, When I speak my transmit
meter swings all the way to the right, but my external watt meter doesn't lie, so it's back to studying all the info I have found at CBtricks web site. I must say I have never heard a radio that sounds like this and you got to love the "Ping" Thanks
Chester 221
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Jan 6, 2011 7:57:53 GMT -5
Just an update, and thanks for the input fellas, I replaced the 7558 transmitter tube and cleaned and re-tensioned the tube sockets and bingo I am now transmitting, I have a very low dead key , around 1 watt and no swing at all. Had my son talk on it as I took off in my mobile, the audio and modulation is really superb, but not much of a carrier if that makes sense. I'm up and running, When I speak my transmit meter swings all the way to the right, but my external watt meter doesn't lie, so it's back to studying all the info I have found at CBtricks web site. I must say I have never heard a radio that sounds like this and you got to love the "Ping" Thanks Chester 221 When you replace tubes, it's often necessary to touch up the alignment, especially the plate tuning cap, which should be accessable at the rear panel. |
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Post by chester on Jan 6, 2011 19:18:27 GMT -5
Thanks Sandbagger, Is there a specific procedure to adjusting that cap? I see where it"s at and I don't doubt someone has messed with it in the past. Sorry for the stupid questions, I'm learning here.
Chester 221
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Post by railroader on Jan 6, 2011 19:51:04 GMT -5
also that mode switch DO NOT CLEAN IT WITH CONTACT CLEANER the radio will have a heart attack the mode switch is still avialible but its a nightmare to install.
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Jan 7, 2011 15:31:19 GMT -5
Thanks Sandbagger, Is there a specific procedure to adjusting that cap? I see where it"s at and I don't doubt someone has messed with it in the past. Sorry for the stupid questions, I'm learning here. Chester 221 It's fairly simple. Key the transmitter and adjust for maximum power. |
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Post by gator7 on Jan 8, 2011 8:15:30 GMT -5
Nice to see another bird saved from the scrap pile. |
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Post by chester on Jan 22, 2011 20:49:17 GMT -5
Thanks for all the input fellas, I got her up and running and have a Maverick 250 in back of it , it really steps right out there !!! I am gathering the parts for a complete cap job, it is a work in progress. Fantastic radio. 73"s
Chester 221 Central Oregon
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Sandbagger
Administrator/The Boss
Posts: 6,250
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Post by Sandbagger on Jan 22, 2011 22:50:05 GMT -5
Thanks for all the input fellas, I got her up and running and have a Maverick 250 in back of it , it really steps right out there !!! I am gathering the parts for a complete cap job, it is a work in progress. Fantastic radio. 73"s Chester 221 Central Oregon Glad to hear that. Sounds like you have a great classic radio station. Here's hoping you get many hours of enjoyment out of it....  |
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Post by SIX-SHOOTER on Jan 22, 2011 23:08:49 GMT -5
I LOVE my BROWNING GOLDEN EAGLE MKIII that I just bought YESTERDAY with the matching BROWNING 776 microphone.I had to put a NEW 2 amp fuse in the receiver & a NEW light bulb in the transmitter channel selector & she works 100% & looks ALMOST "MINT" & cost me a BIG $75 TOTAL.(NOT counting the fuse & bulb)}:>) She sounds "SWEEEEEEET" with her LONG PING. }:>) ;D
SIX-SHOOTER
OT66
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