Maxcom 20e (27/81) Help Please!

Good evening all,

I was given an old Maxcom 20e, I have powered it up and connected to a good antenna T2LT type and getting SWR reading of 1.1 to 1.3 which is spot on. I have also tested power which appears to be around 2.5 to 3w which isn't very high tbh but it appears to be transmitting. I have then tried to test calling out on a channel to a WEBSDR 8.5 miles away and I can see on the 'waterfall' a signal trace when I transmit however I do not appear to be getting any modulation / voice. Unfortunately, I don't have another 5 pin din microphone to test to see if the microphone is at fault. 
Does anyone have any suggestions?

I don't want to sink too much money into it and not get anywhere when I could just buy another cheap modern rig tested and guaranteed.

Welcome any thoughts on possible cause of issue. 

Thanks,

Tony

Hi Tony,

I feel your pain and unfortunately a 'simple' answer is going to be very dependant on your situation.

As you say, you don't have another microphone and I suspect you don't have another receiver to check against or test gear to measure it.
You could guarantee peace of mind by sending it for a service but then finding a reputable engineer who isn't going to try and rip you off with woes of recapping is going to be difficult. Even if you find a reputable engineer it'll cost you money regardless and probably as much as purchasing another CB nowadays.

I would suggest you call out for a radio check but unless you have a busy area CB wise you could be shouting into dead air whether it is working or not. If you have a friend with a CB also you can obviously check with them and their rig but I would've thought that would be an obvious solution that hasn't presented itself.

We have had in the past on the Charlie Tango forum very helpful members swing by another members QTH to give them a shout out on air but I only recall this happening a couple of times. If there's anyone reading this from the Manchester area maybe they'd kindly offer?

Other than that I'm at a loss to suggest further.


Does this webSDR near you have much traffic with FM CB signals? (I suspect it's a "KiwiSDR"?)

Its just that if you have no radio traffic in your area buying a new FM CB might prove fruitless if there's no one in your area using that service. A lot of CB'ers nowadays seem to be using SSB or sideband radios and a lot of the 'nets' are on those EU/CEPT frequencies. No surprise really as those SSB transmissions tend to carry further than FM and there's better opportunities for DX work.

I can only wish you well and hope you find a solution.


All the best,
Victor

Hi Tony. I don't know that radio. I have done a quick net search on it and it looks like it has the same 5 pin din mic plug that the old 4e model used. Those types of push in plugs and get a bit loose over time, it might be that one of the wires is not making a connection.

You could try giving the mic lead and plug a little waggle whilst you're talking into it to see if there is a loose connection or possible wire break in the lead.

Hi SangueG,

That is a very good suggestion, I will try that next time I have it wired up. To be honest the CB radio has spent the last 30 years in a tractor cab so as you can imagine the radio and microphone have seen better days.
I will give it a go and see if it makes a difference.

Many thanks,

Tony

Victor wrote:

Hi Tony,

I feel your pain and unfortunately a 'simple' answer is going to be very dependant on your situation.

As you say, you don't have another microphone and I suspect you don't have another receiver to check against or test gear to measure it.
You could guarantee peace of mind by sending it for a service but then finding a reputable engineer who isn't going to try and rip you off with woes of recapping is going to be difficult. Even if you find a reputable engineer it'll cost you money regardless and probably as much as purchasing another CB nowadays.

I would suggest you call out for a radio check but unless you have a busy area CB wise you could be shouting into dead air whether it is working or not. If you have a friend with a CB also you can obviously check with them and their rig but I would've thought that would be an obvious solution that hasn't presented itself.

We have had in the past on the Charlie Tango forum very helpful members swing by another members QTH to give them a shout out on air but I only recall this happening a couple of times. If there's anyone reading this from the Manchester area maybe they'd kindly offer?

Other than that I'm at a loss to suggest further.


Does this webSDR near you have much traffic with FM CB signals? (I suspect it's a "KiwiSDR"?)

Its just that if you have no radio traffic in your area buying a new FM CB might prove fruitless if there's no one in your area using that service. A lot of CB'ers nowadays seem to be using SSB or sideband radios and a lot of the 'nets' are on those EU/CEPT frequencies. No surprise really as those SSB transmissions tend to carry further than FM and there's better opportunities for DX work.

I can only wish you well and hope you find a solution.


All the best,
Victor

Hi Victor,

I have replied separately to your message above however I am not sure whether it has posted for some reason. I got a message to say it had posted successfully.

Regards,

Tony

Hi Victor,

Thank you for your reply and words of wisdom. The WEBSDR I am able to activate is near Jodrell Bank (G0XBU). I do actually have another old rig (uniden uniace 100) that needs wiring up and testing so I will probably try that next. I know the internal speaker on that CB isn't working and so I have ordered an external speaker to try it with as I can hear the squelch with head phones plugged into the external speaker port. 

I will probably sort the uniden out and rig to another antenna to see if the Maxcom is transmitting with modulation (fingers crossed). 

As you correctly assumed I have not test equipment and only a layman's understanding of radio equipment. As you say, based on the age of both my radios a radio service engineer would likely want to have them re-capped. 

As you say I get the impression many have moved over to SSB / Sideband. Other than FM channel 19 I can hear alot of activity on USB on the WEBSDR. If I do go down the new rig route I need to have a good think about whether I just go for a SSB radio from the off. Aside from them being noticeably more expensive there seems to be limited choice unless you are using HAM gear which I understand most use but is frowned upon by OFCOM. 

I will keep having a play over the next few weeks and see if I can make sense of it all at minimum cost. If I don't get anywhere then I will be seriously considering the new multistandard or multimode rig. I am probably leaning towards multimode notwithstanding your comments and that there appears to be more activity on the sidebands, it seems to leave you with more options this way.

Thanks again for your help. 

73s

Tony

The micrrophone elements on these are known for failing.

Moisture from breath makes the internals corrode, and that prevents the moving part from moving and making sound.

I had a 20E as my first radio, they work ok but are a bit of a bleedover box. That won't matter too much these days however.

Do you have a soldering iron?.
If yes I would cut the mic plug off about an inch back then er solder the wires back one by one so you get the right wiring. 
They where a pain in the but the plug on them they have no support if you get what I mean.

Mudslinger wrote:

The micrrophone elements on these are known for failing.

Moisture from breath makes the internals corrode, and that prevents the moving part from moving and making sound.

I had a 20E as my first radio, they work ok but are a bit of a bleedover box. That won't matter too much these days however.

Hi Mudslinger,

Thank you for your message. It is the original microphone and it is in a very poor state and so it is probably worth taking the plunge and getting a new microphone. 

I have heard Maxicom units were known for this, as you say probably not a major issue with today's activity on the band.

Many thanks,

Tony

Alan Pilot wrote:

Do you have a soldering iron?.
If yes I would cut the mic plug off about an inch back then er solder the wires back one by one so you get the right wiring. 
They where a pain in the but the plug on them they have no support if you get what I mean.

Hi Alan,

That is a fair point. Probably not helped by the side socket instead of the front sockets which are the norm these days. Unfortunately, the plug end is the original moulded type 5 pin Din plug and so I would need to replace the plug if I was to resolder back on. 

The microphone is original but in very poor condition and so I will likely buy a new microphone and go from there. 

Thanks for your suggestion though.

Tony

If you are serious about getting back into radio buy a decent power mic.
It could be handy when you get an ssb radio but don’t bother with a echo type.
And buy a 5 pin din plug extra to test that radio.

If I remember rightly, these sets do not have a PA switch.  Shame, it would have made it easy to find out if the mic is working by plugging in an extension speaker.
However, what you can do is this:
It is fitted with a 5 pin din plug, these corrode, pull the mic plug out and in a good few times, this will scrap off any crud that has built up.
Work the mic switch a lot of times, these corrode inside, usually the audio part of the switch corrodes most, but they all do. 
If you have a small multi meter (or know someone who has) test across the mic insert, it should be around 600 ohms.  If the meter reads nothing, it is open circuit.
If you have a small multi meter or have a loan of one, test each pin going to the mic (inside the mic).
You should get a connection to all wires on the switch.
If you have something that will listen to 27Mhz, just listen for audio after working the mic plug and mic switch.
If you have switch cleaner, give the mic socket in the CB a light spray, then pull it in and out a few times.  Same with the mic switch (do not use WD40).
If the mic appears to be ok, check to see if any electrolytic capacitors around the audio I.C., it will have a heat-sink.  Check to see if it is stained around the base of any electrolytic capacitors, or the plastic has shrunk around the tin can.  If the CB makes a noise, the Audio amplifier itself might be ok, however, check for small holes or cracks on it.
The CB should work, but it may need to be realigned after so many years, especially if it has been stored in a damp place.
If you can get a mic to test the CB, even better.
Hope it helps a bit?

Another thing you can try is to very lightly tap the mic insert, they have been known to stick if it has sat unused for a long time.

BoB4jjjj wrote:

If I remember rightly, these sets do not have a PA switch.  Shame, it would have made it easy to find out if the mic is working by plugging in an extension speaker.
However, what you can do is this:
It is fitted with a 5 pin din plug, these corrode, pull the mic plug out and in a good few times, this will scrap off any crud that has built up.
Work the mic switch a lot of times, these corrode inside, usually the audio part of the switch corrodes most, but they all do. 
If you have a small multi meter (or know someone who has) test across the mic insert, it should be around 600 ohms.  If the meter reads nothing, it is open circuit.
If you have a small multi meter or have a loan of one, test each pin going to the mic (inside the mic).
You should get a connection to all wires on the switch.
If you have something that will listen to 27Mhz, just listen for audio after working the mic plug and mic switch.
If you have switch cleaner, give the mic socket in the CB a light spray, then pull it in and out a few times.  Same with the mic switch (do not use WD40).
If the mic appears to be ok, check to see if any electrolytic capacitors around the audio I.C., it will have a heat-sink.  Check to see if it is stained around the base of any electrolytic capacitors, or the plastic has shrunk around the tin can.  If the CB makes a noise, the Audio amplifier itself might be ok, however, check for small holes or cracks on it.
The CB should work, but it may need to be realigned after so many years, especially if it has been stored in a damp place.
If you can get a mic to test the CB, even better.
Hope it helps a bit?

Hi BoB4jjjj,

Thank you for your message. Some really good suggestions there. I do have a multi meter and so can perform the checks you mention. As you say this model does not have a PA output which would make it a lot easier to rule out a faulty mic. I will give your suggestions a try and see if I can get to the bottom of it. 

Many thanks,

Tony