Search found 157 matches

by lbcomms
Friday 13th Jun 2014, 1:31
Forum: CB Radio Repair and Troubleshooting
Topic: Cobra 29 LTD Classic, no output
Replies: 25
Views: 26208

Re: Cobra 29 LTD Classic, no output

I know this is a very very VERY old thread but I came across it while trying to figure out what the issue is with my Cobra 29 Classic and Cobra 29LX Old thread is something of an understatement :lol: the transmit light comes on and I also get some sort of signal on nearby receivers (several inches ...
by lbcomms
Tuesday 11th Feb 2014, 0:16
Forum: CB Radio Modifications
Topic: Pearce simpson super lion mk 2 info
Replies: 3
Views: 4176

Re: Pearce simpson super lion mk 2 info

The middle can is usually USB - guess you found one of the not so usual ones :o Good to see you got it better. Don't go for perfection with this radio, if you get it "spot on" on Mondays it will drift a bit by Tuesday... if you want drift free buy a better radio. I did not touch the other cans .. wh...
by lbcomms
Sunday 9th Feb 2014, 23:52
Forum: CB Radio Modifications
Topic: Pearce simpson super lion mk 2 info
Replies: 3
Views: 4176

Re: Pearce simpson super lion mk 2 info

They have the same innards as the Lankar DW-1200, read all about it at http://www.radiomods.co.nz/forum/viewtopic.php?f=5&t=3045 Sorry you'll have to manually copy and paste it into a browser, the board has disabled inserting links into a post... Frequency adjustment: http://i60.tinypic.com/2cneesm....
by lbcomms
Sunday 17th Feb 2013, 17:05
Forum: CB Radio Repair and Troubleshooting
Topic: Power Supply - Voltage drop under load
Replies: 51
Views: 33950

Re: Power Supply - Voltage drop under load

Current thoughts are towards building an 8 section coax co-linear with a supposed 9DBi gain, taken from a tried and tested 70cm ham antenna design. (obviously re-calculated to 446mhz) That's only 1.4% above 70cm, a 9dB antenna will have probably 2.5% bandwidth under 1.5:1, so you should be able to ...
by lbcomms
Sunday 17th Feb 2013, 16:44
Forum: CB Radio Repair and Troubleshooting
Topic: Uniden Zachary T no tx or rx?
Replies: 4
Views: 4298

Re: Uniden Zachary T no tx or rx?

How could I test for a bad cap? Would I have to pull to test first? Thanks. From an electronics and communication engineer with 16 years experience: you don't. Replacing ALL of them is the only way to make these sets reliable. If we get in any pre-2000 Uniden chassis for repair, we now insist on re...
by lbcomms
Sunday 17th Feb 2013, 0:48
Forum: CB Radio Repair and Troubleshooting
Topic: Uniden Zachary T no tx or rx?
Replies: 4
Views: 4298

Re: Uniden Zachary T no tx or rx?

The most common problem with these 80's / 90's Unidens (except for the golden screwdriver syndrome) is the "10 volt blues". There will be 15 to 30 light grey 10V electrolytic capacitors, these fail (start to conduct DC, something an electrolytic must not do) after 10 to 20 years. Replacing ALL of th...
by lbcomms
Sunday 17th Feb 2013, 0:35
Forum: CB Radio Repair and Troubleshooting
Topic: Power Supply - Voltage drop under load
Replies: 51
Views: 33950

Re: Power Supply - Voltage drop under load

please note that it is not a good idea to re-open posts that are long-dead (more than 2 years in this case) as the original poster is usually long gone. Hi Warf135, we are still around, though i don't get as much time for forums as I used to. How are things up there in the UK? Determine a good smal...
by lbcomms
Monday 27th Feb 2012, 22:00
Forum: CB Radio Modifications
Topic: GME tx842 clarifier mod
Replies: 5
Views: 3727

Re: GME tx842 clarifier mod

hot side of the pot has 2.8v but the cold side goes into the rf gain pot Doesn't matter. Isolate these 2 connections and connect the pot terminals to +V and ground respectively. delta force magnum has a 5v regulator No need for that. There is a regulator in the 8 or 9 volt range present in nearly e...
by lbcomms
Sunday 26th Feb 2012, 23:31
Forum: CB Radio Modifications
Topic: GME tx842 clarifier mod
Replies: 5
Views: 3727

Re: GME tx842 clarifier mod

There are many variations on this chassis, so instructions like "cut the pink wire and join the green and brown together" usually won't work, and may even kill your radio! You need to have some basic idea what you are doing (or take it to someone who does). Only basic gear needed - soldering iron, m...
by lbcomms
Thursday 23rd Feb 2012, 0:25
Forum: CB Radio General
Topic: which mic. is the best...
Replies: 6
Views: 6419

Re: which mic. is the best...

The mic MUST have the same impedance (resistance) as the radios mic input (600 ohm - 1Kohm) With RF (sch as the antenna circuit) that's true, but it's a bit different for audio. With audio, the source (mic) needs to have a much lower impedance than the load (radio). Most mics are in the 50 to 750 o...
by lbcomms
Wednesday 22nd Feb 2012, 23:41
Forum: CB Radio General
Topic: Lankar DW-1200
Replies: 6
Views: 5471

Re: Lankar DW-1200

They are almost as bad as a DW-1200! The Lankar unit was a far worse "radio" - the PC122 might drift a bit, but at least they were reliable. We had about a 2% to 3% warranty failure rate on the '122, the Lankar units were 80%+. Therefore, going by the warranty returns, the Lankars were 40 times wor...
by lbcomms
Tuesday 24th Jan 2012, 0:06
Forum: CB Radio Modifications
Topic: Cobra 29 NW LTD Classic Mods? (New guy)
Replies: 2
Views: 6575

Re: Cobra 29 NW LTD Classic Mods? (New guy)

what are the most effective mods for the time/money? With that radio, not too many. 29's are made to look pretty and be a convenient size for modern SUVs, but as a radio they are fairly mediocre. Is the 520 or the 2030 going to do better? Or should I stick with the 1969, even? Is the 2sc2312 same/b...
by lbcomms
Monday 19th Dec 2011, 13:11
Forum: CB Radio Modifications
Topic: cobra 146 GTL mod ?
Replies: 9
Views: 6731

Re: cobra 146 GTL mod ?

the am side worked perfectly
:lol: That would be like putting skinny bald tires on a Mustang and saying "That's OK, because only use it to drop the kids off to school"
by lbcomms
Friday 16th Dec 2011, 20:59
Forum: CB Radio Modifications
Topic: cobra 146 GTL mod ?
Replies: 9
Views: 6731

Re: cobra 146 GTL mod ?

a galaxy A kit will work in them. Also a expo 100 "N" kit will work Depends on your definition of "work" :) The '2824 PLL clarifies and does the SSB offsets by varying the 10.240 frequency slightly. This is halved and then tripled to 15.360 and mixed with the VCO. The offsets are preserved by this ...
by lbcomms
Sunday 23rd Oct 2011, 15:55
Forum: CB Radio General
Topic: HELP! Cherokee NightRider 150 ?'s
Replies: 1
Views: 2311

Re: HELP! Cherokee NightRider 150 ?'s

point me in the direction of an owners manual maybe Google the owners manual for "Uniden Grant", "President Grant", or "Cobra 148". The controls might be in a slightly different place but all of the above are almost identical - the only real difference is the Grant doesn't have the inbuilt SWR meter.
by lbcomms
Tuesday 18th Oct 2011, 0:49
Forum: CB Radio Modifications
Topic: tti TCB-880
Replies: 1
Views: 2461

Re: tti TCB-880

Can you mod the tti TCB-880 cb radio from 80 channel too 400 channel 1) Yes you can, any radio can be modded. Some are far easier than others though. We played around with a very similar one about 3 ago. Got it to do lots of strange things by adding random data to EEPROM IC802 :) OK so I was bored....
by lbcomms
Saturday 3rd Sep 2011, 12:25
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

That's correct, and why inverted (common to ground) switches are used on most real-world applications.
If you want to play safe, put a low value resistor (say 68 ohms) in the 5V line that feeds both switches, this will limit the current to a safe value (about 75mA) in the event of a short.

Cheers
by lbcomms
Friday 2nd Sep 2011, 11:47
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

First of all, make sure they are not inverted - when the switches are at position "0", there should be NO connection between any of the pins (assuming they are 5 pin switches). If they have more than 5 pins, there should be NO connection between any of the output pins at position "0". Repeat the abo...
by lbcomms
Friday 26th Aug 2011, 13:01
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

where do the resistors and capacitor come into it? It depends on the switch design - there are 2 types of hex switch. I only showed the least common type before as it's easier to understand. These have the common connected to +5V and the outputs are used directly. There is one problem with that app...
by lbcomms
Friday 26th Aug 2011, 0:18
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

Cheap hex switches in the UK: http://www.ebay.co.uk/itm/HEX-RED-KNOB-CONTROL-PCB-MOUNT-SWITCH-QTY-1-/110620408748?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item19c17d7bac Mount them on some perf board and wire them to the (with the EPROM now removed) EPROMs data connections. Or, if the EPROM ...
by lbcomms
Thursday 25th Aug 2011, 11:55
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

The output data in theory could be found by using a truth chart for the MC145106 PLL chip No, as this can change for different radio designs. Old school PLLs like the MC145106 were not fast enough to directly control the VCO frequency, so downmixing had to be used so that the thing could work. RF m...
by lbcomms
Thursday 25th Aug 2011, 0:56
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

Here's the pinout of the EPROM: http://i55.tinypic.com/fop3m9.gif The address lines are the inputs to the EPROM. The first digit (thousands) is A12. This can only be high (1) or low (0). The next digit (hundreds) is A8, A9, A10, and A11, so this can be 0 through to F. The next digit (tens) is A4, A5...
by lbcomms
Wednesday 24th Aug 2011, 15:44
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

Where's the fun in that? :D sounds like it will be a lots of maths involved Hex 101: Numbers in computers (and radios!) are represented by voltages on wires - these can either be off (low) or on (high). By putting different voltages on different wires, we can "change" things (such as our operating f...
by lbcomms
Wednesday 24th Aug 2011, 11:57
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

"4 of the programmable output pins of the eprom are dead" They are all OK, all 8 lines working are needed to show the numbers you have in the hex dump. However, it looks like data line D4 (the least sig bit of the tens digit) is in trouble - nearly (but not all) of the combinations are high. This i...
by lbcomms
Monday 15th Aug 2011, 1:13
Forum: CB Radio Modifications
Topic: JD Custom LC2 (iss1) Eprom conversion - TC9119
Replies: 38
Views: 23919

Re: JD Custom LC2 (iss1) Eprom conversion - TC9119

I have an old major M588 in the shed
There is a PLL02A version of the scanner app - hook that up and you'll have more channels than you would now what to do with :lol:

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