| Author |
Message |
    
Mojoe
New member
Username: Mojoe
Post Number: 1
Registered: 4-2007
| | Posted on Saturday, July 07, 2007 - 5:36 pm: | 
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I have recieved a robyn base radio when I hook it up it sounds like thier isn't an antenna.My antenna is fine when some one talks local I can hear them with volume all the way up.When I key and talk I can see on my other radio its keying up but no out put.And last but not least when put on ssb and key it shorts out fuse. If anyone can help I would greatly appreciate it. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2574
Registered: 9-2004
| | Posted on Saturday, July 07, 2007 - 9:21 pm: |
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it sounds like you might have more than one problem.
one VERY common problem with this chassis is that C179, which is a small blue tantalum capacitor near the final and driver, goes bad, causing low, to no TX output, and blowing fuses.
replace this cap with a 2.2uF electrolytic capacitor rated at no less than 25 volts.
higher voltage rating is fine, as long as the part will physically fit.
WATCH THE POLARITY!!!
there will be a small "+" symbol near one of the holes for the leads.
make sure this lines up with the "+" lead on the new electrolytic capacitor.
should be able to get this part at radio shack.
after replacing this part, you may still have problems.
post what they are, and we'll work from there.
good luck,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Mojoe
New member
Username: Mojoe
Post Number: 2
Registered: 4-2007
| | Posted on Tuesday, July 10, 2007 - 9:28 pm: |
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Cool the capacitor worked for my out put and no more shorting out on ssb. Now my recieve is still very weak. I have my rf turned up inside and out no change.My other radio is holding 7db of skip noise right now and the robin has nothing, only when a strong signal hits or local talk I can hear with volume turned all the way up. |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2587
Registered: 9-2004
| | Posted on Tuesday, July 17, 2007 - 2:46 pm: |
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glad the cap worked for you.
as for the weak receive, it could be misaligned, or it could be a bad component or components.
TR5 is your 1st RF amp.
this is just a guess, but you might try replacing it.
you can use a 2SC945 that you can find anywhere for cheap.
you must re-tune the RX coils if you replace the transistor.
they are L8-L3, and should be tuned in that order.
L4 is a double coil and can be used to balance the RX on ch.1 and 40.
do the receive tune up on ch. 19 or 20.
the best way is to have a mobile key up however you can do it so that it reads no more than S-5 on your meter.
then, using a plastic tuning tool, very slowly turn the cans for the maximum S-meter reading.
you will notice that at one point there is a "peak" level. leave it there.
after you are done, go back and repeat the process as they interact with eachother somewhat.
some models will have L6, and some wont.
dont turn the internal VR for RF gain all the way up. it creates too much internal noise in the radio.
turn it up about 2/3 to 3/4 of the way.
again, these are just guesses, and you may have other problems due to the age of the radio.
best of luck,
matt
anyone wanting a "clean signal", just look to the left and build one of these!!!
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Shawn1506
New member
Username: Shawn1506
Post Number: 1
Registered: 1-2013
| | Posted on Tuesday, January 15, 2013 - 8:35 am: |
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I recently hooked up my base radio with my A99 on the chimney. It has been years since I have even looked at this stuff so please bare with me. I Have been talking along on my radio with a good SWR of about 1.2 on channel 1 and about a 1.4 on channel 40 for about a week or so. Well the other night my buddy and I were talking and I decided to try out the LSB on the radio. I flipped the switch and listened and got him tuned in. I keyed the mic and as soon as i spoke, the 3 amp fuse blew in the back of my radio. I replaced the fuse with a 2.5 amp fast acting, so not to hurt the radio, then turned back to AM. Now every time I key up and speak on AM the fuse blows. Does anyone have any idea what this may be? The radio has had channels put in it about 30 years ago. but other then that this radio is stock and in very good shape. I thank you for your help in advance.
Shawn |
Ronin
Member
Username: Ronin
Post Number: 90
Registered: 8-2006
| | Posted on Tuesday, January 15, 2013 - 9:04 pm: |
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What kind of radio? I will assume that it is a Robyn SB 520D since your post was added to this thread. If so, some of the radios that used the same board as the Robyn 520 had issues with the 3A fuses blowing on SSB. The tech notes refered to simply using a 4 amp fuse since the 3A was running right at it's limit when transmitting on SSB.
My Cobra 139XLR is in this category with regards to the fuse issue. The Robyn 520D and the Cobra 139XLR used the same circuit board, so it is probably having the same issues. You can find some of this information online. For the Cobra 139XLR, it was Technical Bulletin #1215.
Jim
CEF-813
K3ZOR
OT-235
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Cb_classic_guy
New member
Username: Cb_classic_guy
Post Number: 1
Registered: 6-2014
| | Posted on Saturday, June 07, 2014 - 7:52 pm: |
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I'm having similar issues on receive with my Robyn 520D... But also, something very puzzling to me is my model is a newer one and has with swr meter on left it also has modulation on that meter. For the life in me, I can NOT figure out how it works. I asked the tech from Coppers over the phone about this and he told me they made several models of this radio while it was out. I might need to call him back regarding this meter I'm totally baffled. But this radio is sweet...
Hope someone is in the know here perhaps on the modulation meter, a rare find on this model it appears ! |
Cb_classic_guy
New member
Username: Cb_classic_guy
Post Number: 2
Registered: 6-2014
| | Posted on Sunday, June 08, 2014 - 10:10 pm: |
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I'm adding a photo so you all can see these meters I'm talking about ! Will somebody respond if they know ANYTHING on this please ? |
