Search found 432 matches

by The Defpom
Friday 29th Jan 2010, 9:35
Forum: CB Radio General
Topic: Wasp CB Mike Connections
Replies: 2
Views: 2263

Re: Wasp CB Mike Connections

I just got one of these in to repair, so can answer this question now.

1 - Audio
2 - Common
3 - RX
4 - TX
by The Defpom
Tuesday 26th Jan 2010, 8:56
Forum: CB Radio Repair and Troubleshooting
Topic: Old rig in need of some TLC perhaps?
Replies: 10
Views: 6923

Re: Old rig in need of some TLC perhaps?

Well that is interesting !

OK, can you find the main PCB's number and tell us what that is, it is likely that it is the same as some other radio inside, if we know the PCB number we will be able know what to base repair advice on.
by The Defpom
Monday 25th Jan 2010, 12:44
Forum: CB Radio Repair and Troubleshooting
Topic: SUPERSTAR 360FM EPROM
Replies: 38
Views: 16798

Re: SUPERSTAR 360FM EPROM

move the array back first, I was incorrect in thinking it could have been in the wrong holes.
by The Defpom
Sunday 24th Jan 2010, 14:54
Forum: CB Radio Repair and Troubleshooting
Topic: Old rig in need of some TLC perhaps?
Replies: 10
Views: 6923

Re: Old rig in need of some TLC perhaps?

Going by the diagram if the TX LED is on, then the radio is transmitting, as it is powered from the RF output, either that or TR11 has failed. Check the voltages on TR21 (D14), this is the TX/RX switch and should provide 9V or so in RX, and 0V in TX, D14 is the RX voltage regulator, as this switch i...
by The Defpom
Saturday 23rd Jan 2010, 7:35
Forum: CB Radio Repair and Troubleshooting
Topic: Old rig in need of some TLC perhaps?
Replies: 10
Views: 6923

Re: Old rig in need of some TLC perhaps?

Hi, Most radios can be repaired, given the right amount of time investment, and parts availability, the tricky thing is having the test gear available to be able to find the faults, at the minimum you will need a power meter with a dummy load (or tuned antenna), a multimeter, a mic which is known to...
by The Defpom
Wednesday 20th Jan 2010, 4:48
Forum: CB Radio Repair and Troubleshooting
Topic: SUPERSTAR 360FM EPROM
Replies: 38
Views: 16798

Re: SUPERSTAR 360FM EPROM

It looks like I steered you wrong there, put the array back where it was, that is what I get from going by memory.
by The Defpom
Saturday 16th Jan 2010, 11:17
Forum: CB Radio Repair and Troubleshooting
Topic: SUPERSTAR 360FM EPROM
Replies: 38
Views: 16798

Re: SUPERSTAR 360FM EPROM

I mention the possible bad etching issue as I have come across it myself on one of my own EPROM PCBs, where a program line worked fine until a different band was selected, as the resistive effect of a partial bridge by copper residue from the band selection input dragged a program line voltage off w...
by The Defpom
Saturday 16th Jan 2010, 7:53
Forum: CB Radio Repair and Troubleshooting
Topic: SUPERSTAR 360FM EPROM
Replies: 38
Views: 16798

Re: SUPERSTAR 360FM EPROM

It could be a badly etched PCB, get a fine knife blade and run it down between every single track on the EPROM PCB, the slightest residue of copper could cause an incorrect input to be seen by the EPROM, you may not even be able to see that the copper is there. I assume that you have tried adjusting...
by The Defpom
Sunday 10th Jan 2010, 21:03
Forum: CB Radio Repair and Troubleshooting
Topic: No Tx audio on cobra 148 GTL
Replies: 8
Views: 5893

Re: No Tx audio on cobra 148 GTL

Great, at least it was TR26.

Now just to sort the meter...
by The Defpom
Monday 4th Jan 2010, 12:11
Forum: CB Radio Repair and Troubleshooting
Topic: No Tx audio on cobra 148 GTL
Replies: 8
Views: 5893

Re: No Tx audio on cobra 148 GTL

With R128 in place, try lifting one end of R161 (this is the SSB ALC feed), I just want to ensure that it is not staying turned on in AM.
by The Defpom
Friday 1st Jan 2010, 1:29
Forum: CB Radio Repair and Troubleshooting
Topic: No Tx audio on cobra 148 GTL
Replies: 8
Views: 5893

Re: No Tx audio on cobra 148 GTL

Try lifting one end of R128 and see if that restores normal TX audio with TR24 in place, if it does then the fault is (or around) TR26 or its feed from the AM TX power control. Some of your voltage readings are a bit odd, please recheck TR25 and TR26 readings. I found my notes, it was on a sister ch...
by The Defpom
Thursday 31st Dec 2009, 0:50
Forum: CB Radio Repair and Troubleshooting
Topic: No Tx audio on cobra 148 GTL
Replies: 8
Views: 5893

Re: No Tx audio on cobra 148 GTL

This symptom sounds familiar, it sounds like the TR24 is loading down the DC supply feeding the audio circuit, so its killing it, you are replacing TR24 with a 2SC945 ? I will have to look up this in my notes, I may be able to direct you to a likely part at fault. As to your meter fault, try replaci...
by The Defpom
Thursday 31st Dec 2009, 0:45
Forum: CB Radio Repair and Troubleshooting
Topic: President Lincoln no RX/TX
Replies: 3
Views: 2552

Re: President Lincoln no RX/TX

I would say to start off by trying to do an alignment and seeing what frequencies are missing or incorrect, as that can give a clue as to the location of the fault. A common problem with this chassis is aging surface mount ceramic capacitors or electrolytic capacitors on the MPU PCB, some of the ele...
by The Defpom
Thursday 24th Sep 2009, 12:51
Forum: CB Radio Repair and Troubleshooting
Topic: 2 differant power levels on ssb
Replies: 3
Views: 2033

Re: 2 differant power levels on ssb

The problem is probably the crystal filter, it may be filtering out the LSB sideband, I have come across this myself before on the same chassis, I had to retune the LSB offset and I.F. to be closer to the centre channel freq to get more of it into the passband of the filter.
by The Defpom
Sunday 13th Sep 2009, 0:24
Forum: General
Topic: expired trial apon instulation
Replies: 9
Views: 9569

Re: expired trial apon instulation

OK, the new version is up on the site now, it is up to version 1.3.0 now. I have added a couple more PLL's to the simulator, and done some other bits and pieces to tidy up some things. I have not tested it on Windows, as I do not have a machine here, as I am on a Apple Mac, but it should work OK. Th...
by The Defpom
Friday 11th Sep 2009, 2:12
Forum: General
Topic: expired trial apon instulation
Replies: 9
Views: 9569

Re: expired trial apon instulation

Because it has been a while since I last did an update to the software I have found that it has needed a lot of work due to changes with the way the compiler works now, I have fixed 2 problems, I only have one issue left, which is purely a display issue, the program still works, but I want to fix th...
by The Defpom
Wednesday 9th Sep 2009, 12:42
Forum: General
Topic: expired trial apon instulation
Replies: 9
Views: 9569

Re: expired trial apon instulation

Interesting, the demo should have expired at the end of 2010, I have just downloaded the latest software which was used to make the program, and will have a new version up on the site soon with some luck, I will post here once it is ready for you to download again.
by The Defpom
Monday 24th Aug 2009, 8:16
Forum: CB Radio Repair and Troubleshooting
Topic: Stalker IX low TX audio
Replies: 5
Views: 2618

Re: Stalker IX low TX audio

Try turning down the AM TX power to 4W and see if the AM TX audio comes right, 10W is too much, if the power output does not change when the VR as adjusted it gives a clue as to where the problem may be.
by The Defpom
Sunday 16th Aug 2009, 1:32
Forum: CB Radio Repair and Troubleshooting
Topic: Rotel 240 noisy TX
Replies: 1
Views: 1244

Re: Rotel 240 noisy TX

Check the PCB for any signs of cracked traces or bad solder joints, years ago when I still lived in the UK I have one of those with the same issue and it was caused by a PCB fault.
by The Defpom
Sunday 16th Aug 2009, 1:30
Forum: CB Radio Repair and Troubleshooting
Topic: GME Electrophone TX830N
Replies: 2
Views: 2324

Re: GME Electrophone TX830N

Dont use trademe, use http://www.ezyauctionz.co.nz instead it is free, faster and safer, (but I am biased). The LED bargraph display should light up in TX, if you cannot hear anything on RX it looks like the radio is a dud, it is probably fixable, but it is likely the fix will be more than the radio...
by The Defpom
Sunday 16th Aug 2009, 1:09
Forum: CB Radio Alignments
Topic: Magnum S9 PCB layout(bottom view)
Replies: 1
Views: 1911

Re: Magnum S9 PCB layout(bottom view)

Sorry, I have been really slack and not been around much lately, so I only just found this post, I have attached the layout you asked for.
by The Defpom
Sunday 16th Aug 2009, 0:49
Forum: Wanted !
Topic: channel selectors needed for 858 chasis radios
Replies: 2
Views: 2162

Re: channel selectors needed for 858 chasis radios

I do not have any selectors, and have not found a good source either, however, I have recently designed and made my own digiscan type units, so far I have made 3 of them, and am still refining the design, but they do work, let me know if you may be interested in one of these. They cover 25.995-28.00...
by The Defpom
Friday 20th Mar 2009, 6:57
Forum: CB Radio Repair and Troubleshooting
Topic: Cobra 29 No Keyup
Replies: 18
Views: 8422

Re: Cobra 29 No Keyup

Replace R98 anyway, as the current flow through it could be causing it to change value, I have seen that happen myself before.

If you do not get 5V at D19 with R124 lifted then the fault can only be R98 or D19.
by The Defpom
Thursday 19th Mar 2009, 15:09
Forum: CB Radio Repair and Troubleshooting
Topic: Cobra 29 No Keyup
Replies: 18
Views: 8422

Re: Cobra 29 No Keyup

Z10 on the diagram I was using may be called D19 in your radio, it is a 5V Zener diode, you should be seeing 5V across it, if not then check R98 (56 Ohm), as that feeds the 8V to the Zener, so R98 should have 8V on one side and 5V on the other, if the 8V is present but the 5V is not, then it could b...
by The Defpom
Thursday 19th Mar 2009, 14:42
Forum: CB Radio Repair and Troubleshooting
Topic: Cobra 29 No Keyup
Replies: 18
Views: 8422

Re: Cobra 29 No Keyup

Go back and read my last post, I asked for voltages at some points, this is to determine where the fault may be.

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