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by The Defpom
Wednesday 7th Dec 2016, 21:11
Forum: CB Radio Repair and Troubleshooting
Topic: Uniden 980ssb
Replies: 3
Views: 1298

Re: Uniden 980ssb

I would just try replacing the diode with a new one and seeing if it works.

I don't have any info such as diagrams for them yet.
by The Defpom
Friday 12th Dec 2014, 7:55
Forum: CB Radio Repair and Troubleshooting
Topic: GME Electrophone final replacement
Replies: 12
Views: 5999

Re: GME Electrophone final replacement

It is a 2SC2078, I do not know if RS stocks them.
by The Defpom
Saturday 7th Sep 2013, 14:45
Forum: Shout Outs
Topic: I'm famous
Replies: 7
Views: 7016

Re: I'm famous

It's good to see you are still around!
by The Defpom
Tuesday 15th Jan 2013, 20:43
Forum: CB Radio Repair and Troubleshooting
Topic: Electrophone GME TX840B SSB Low Power
Replies: 1
Views: 1878

Re: Electrophone GME TX840B SSB Low Power

I dont have any info on that model myself, but it sounds more like a bad capacitor (or a few of them) in the audio path, effectively hi-passing the audio, cutting off the lower tones.

An incorrect SSB offset calibrations could also be possible, resulting in the frequencies being cut by the IF filter.
by The Defpom
Tuesday 15th Jan 2013, 20:39
Forum: CB Radio Repair and Troubleshooting
Topic: Cb not receiving
Replies: 3
Views: 2787

Re: Cb not receiving

I suspect that it has overloaded the front end of the RX chain, most probably the shunt diodes, D1,D2,D19,D20.
by The Defpom
Monday 12th Mar 2012, 9:49
Forum: RadioMods Members Assistance
Topic: The Old Browning Ping
Replies: 2
Views: 1359

Re: The Old Browning Ping

Sounds like it needs to go to the tx from the mic, I would have to check it though
by The Defpom
Thursday 22nd Dec 2011, 23:11
Forum: CB Radio Modifications
Topic: lincoln HR2510 MRF455 pcb
Replies: 3
Views: 3366

Re: lincoln HR2510 MRF455 pcb

Mount the new MRF455 / SRF3775 on the rear panel on the bottom of the radio instead of the top, much more room there :-)
by The Defpom
Monday 28th Nov 2011, 10:31
Forum: CB Radio Repair and Troubleshooting
Topic: hr2510 president Lincoln CPU
Replies: 26
Views: 9573

Re: hr2510 president Lincoln CPU

It would pay to have a close look at the reset circuit which does a reset every time the radio is powered up, I have seen them fail to produce a sufficient reset pulse time, causing the MCU to not correctly reset. The MCU reset pin is 49, the circuit consists of Q316, Q317, IC314 and a dozen other m...
by The Defpom
Thursday 24th Nov 2011, 20:42
Forum: CB Radio Modifications
Topic: COBRA 148 GTL ADDING FREQ. COUNTER
Replies: 7
Views: 4072

Re: COBRA 148 GTL ADDING FREQ. COUNTER

The only way to read the TX and RX freq on a radio is to hook into the offset oscillator, however, this will not give you the on channel frequency, as it would need to be mixed with another frequency (to match the radios IF), for instance if you hooked into the 148, you would be seeing a 34MHz frequ...
by The Defpom
Thursday 24th Nov 2011, 20:31
Forum: CB Radio Modifications
Topic: lincoln HR2510 MRF455 pcb
Replies: 3
Views: 3366

Re: lincoln HR2510 MRF455 pcb

I have just used some very short hookup wires to the main PCB after mounting the 455 on the rear panel, worked fine, I think I did rogerbirds mod from memory.
by The Defpom
Thursday 24th Nov 2011, 20:24
Forum: CB Antenna Systems
Topic: Made In the USA - SigmaIV ;)
Replies: 14
Views: 4602

Re: Made In the USA - SigmaIV ;)

This is a great post, thanks for sharing it.
by The Defpom
Thursday 24th Nov 2011, 20:14
Forum: Wanted !
Topic: Broken CB's wanted
Replies: 0
Views: 1068

Broken CB's wanted

I am always on the look out for parts radios, especially radios like the HR2510, Lincoln etc.

So if you have anything, please let me know what you have and what you want for it, international shipping may be feasible if it is a radio I particularly want to get for parts.
by The Defpom
Friday 18th Nov 2011, 7:01
Forum: CB Radio Repair and Troubleshooting
Topic: Deaf President George
Replies: 14
Views: 5171

Re: Deaf President George

I found a mistake on the PCB layout, there are two r27 on it, one below q8 and one just to the right of it, one of those will probably be r37, see which one connects to d22/r569 and then q18
by The Defpom
Thursday 17th Nov 2011, 22:15
Forum: CB Radio Repair and Troubleshooting
Topic: hr2510 president Lincoln CPU
Replies: 26
Views: 9573

Re: hr2510 president Lincoln CPU

I got a bunch of used mcu from the guy that was doing the chip switch installations in the USA, you might be able to get some from him, you need to specify the exact mcu number you want, as there are a few variants.

If only I could remember who it is...
by The Defpom
Thursday 17th Nov 2011, 10:46
Forum: CB Radio Repair and Troubleshooting
Topic: hr2510 president Lincoln CPU
Replies: 26
Views: 9573

Re: hr2510 president Lincoln CPU

Am finally home (for today anyway!) had any more progress with this radio ?
by The Defpom
Thursday 17th Nov 2011, 10:38
Forum: CB Radio Repair and Troubleshooting
Topic: Deaf President George
Replies: 14
Views: 5171

Re: Deaf President George

Thanks for the diagram, that was slightly better ! the resistor to lift is R37, not 57.
by The Defpom
Thursday 17th Nov 2011, 9:40
Forum: CB Radio Repair and Troubleshooting
Topic: Deaf President George
Replies: 14
Views: 5171

Re: Deaf President George

Unfortunately the circuit diagram I have for that radio is rubbish, I cannot make out most of the part numbers etc. But the first couple of things I would do is try removing the AGC function in case that is staying turned on, this can be done by lifting R37, Q18 is the AGC control transistor. The RF...
by The Defpom
Sunday 13th Nov 2011, 10:44
Forum: CB Radio Repair and Troubleshooting
Topic: hr2510 president Lincoln CPU
Replies: 26
Views: 9573

Re: hr2510 president Lincoln CPU

Replace it, as it effects the serial communications with other device such as display and plls, I have also come across issues with the factory glue causing shorts to the traces underneath them, so it might pay to clean original glue off, and replace it.
by The Defpom
Sunday 13th Nov 2011, 7:18
Forum: CB Radio Repair and Troubleshooting
Topic: hr2510 president Lincoln CPU
Replies: 26
Views: 9573

Re: hr2510 president Lincoln CPU

Pull and clean every plug on the mpu pcb, also pull the display pcb and resolder it all. Especially the through holes as I have seen those fail killing the display and confusing the mpu. If you have another radio you can pull the display pcb from it helps, as that can eliminate that as the problem. ...
by The Defpom
Sunday 12th Jun 2011, 23:04
Forum: General
Topic: No registration number
Replies: 1
Views: 2135

Re: No registration number

Sorry for the delay, I had been away, I cant process registrations until I get home to generate the serial number.

I emailed you your serial number a few minutes ago.
by The Defpom
Tuesday 22nd Mar 2011, 9:35
Forum: CB Radio Repair and Troubleshooting
Topic: cobra 29 dead
Replies: 7
Views: 2748

Re: cobra 29 dead

Can you please answer EACH of the questions I asked, I need to know the answers to all of them in order to be able to narrow down where the fault could be. On the back of the vol/on/off control there are two connections, usually a red wire and orange wire, you should have 13V on BOTH wires when the ...
by The Defpom
Monday 21st Mar 2011, 22:25
Forum: CB Radio Repair and Troubleshooting
Topic: Uniden Washington-1 watt output
Replies: 3
Views: 1771

Re: Uniden Washington-1 watt output

Alignment info is on the site here: http://www.radiomods.co.nz/pc385align.html
by The Defpom
Monday 21st Mar 2011, 22:23
Forum: CB Radio Repair and Troubleshooting
Topic: President Lincoln control buttons not working
Replies: 9
Views: 4196

Re: President Lincoln control buttons not working

Glad to hear you got it sorted out. An easy way of getting the existing MPU IC out is to actually cut all the pins off the IC, and then desolder and remove them one by one, I found that to be one of the simplest ways of getting a faulty one out, and also helps avoid damaging the PCB traces from exce...
by The Defpom
Monday 21st Mar 2011, 22:13
Forum: CB Radio Repair and Troubleshooting
Topic: cobra 29 dead
Replies: 7
Views: 2748

Re: cobra 29 dead

Does the meter light up? Does the channel display light up? Has the inline fuse blown in its power cord? Have you checked for 13V at the on/off switch to confirm that power is getting to the radio itself ? Have you made sure it is not set to PA mode? You should be getting 5V at D19 with the radio tu...
by The Defpom
Wednesday 9th Mar 2011, 19:36
Forum: CB Radio Repair and Troubleshooting
Topic: President Lincoln control buttons not working
Replies: 9
Views: 4196

Re: President Lincoln control buttons not working

I should drop in here more often by the looks ! I wish I wasn't so busy with other things, anyway. One thing to try, as weird as it will sound, is swap out the LCD PCB, I have seen instances where a faulty LCD PCB has caused the MPU to appear to be faulty, it is a long shot, but an easy thing to rul...

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