Becker Mexico TR Radio - board photos query

[swood1]

Hi all,

Just been looking at my radio (early Becker Mexico TR with seperate amp), unfortunately it's not working.   I have fixed the mechanicals but I can see the I can see the board looks to have been hacked at (photo attached).  I dont suppose someone has a photograph showing this board? 

Photo attached showing damaged connections in yellow and blue.

Regards

Steven

[scoot]

Much to my surprise, I don't seem to have a Mexico TR on my shelves.  I have just about everything else pinstripe...  Before assuming the circuit board has a problem (which it might well) it might help to know a little bit more about the radio.

1.  Has it worked before?
2.  Do you know if the amplifier is good?
3.  If you apply power and turn it on, do you get +12V at the indicator light?

There is a place in Chelsea called Chrome London   (chromelondon.com I think) that sells restored Becker radios.  Don't know if that is of any help...

Scott

[swood1]

Hi Scott

I have no history on the radio. With regards amp is there an easy way to check it? I have replaced the fuse and checkeda the contacts and amp looks good. No i dont see anything at the moment. I am using a cheap power supply which only just powers up another radio i have so wondering if i need to spend some money on a small workshop dc power supply. I am aware of the shop you mention I was just hoping it would be relatively easy fix.

Steve

[scoot]

I have no history on the radio. With regards amp is there an easy way to check it? I have replaced the fuse and checkeda the contacts and amp looks good. No i dont see anything at the moment. I am using a cheap power supply which only just powers up another radio i have so wondering if i need to spend some money on a small workshop dc power supply. I am aware of the shop you mention I was just hoping it would be relatively easy fix.

It might be a relatively easy fix.  When you say you don't see anything at the moment, do you mean when you turn on the radio you get no light?   If you have an ohm meter / volt meter you will want to test the voltage at the base of the bulb and see if you are getting power there.

If easy to do so, add pics of the back of the radio and of the connection to the amplifier.  I don't remember how much current that radio draws but if it's too much I would expect the power supply to flip off rather than do nothing.  If there is an inline fuse in the black wire power cable then the amperage of the fuse might tell you (if it's the right fuse) and if your power supply is lots less than that you might need a better power supply.   Or use a 12 volt battery but use a fuse with that.

The back of the radio should have a black wire coming out.  And a big grey cable with another black wire going into the grey cable.  The cable plugs into the amp and there should be a black wire coming out at the amp side of the cable with a slide-on connector.  On the amp next to the plug there is a grounding terminal to slide the black ground connector to.  The first black wire (opposite the grey cable usually) just gets 12V+ sent to it.  Then you have to ground the radio to the negative of your power supply.  Next you need to connect an antenna.  You can get no or little sound if you don't have an antenna.  I have a cheap antenna that I keep with my test stuff for this purpose.  Then you need speakers plugged into the amp. 

So is that your test configuration?   If it isn't, then I would not worry about the circuit board at this point in time.   

The only way I know of to test an amp is to test it with a known good radio. 

[swood1]

Wow thanks scoot.

Tomorrow I shall revisit the radio and let you know how I get on.


Regards

Steven

[DaveB]

Here's a high-res photo of an equivalent Mexico TR

[swood1]

Thanks Dave.

[scoot]

Steve's radio and Dave's radio do not have the same circuit boards.   Why is Dave's so pristine?  And Steve's kind of goopy looking?   I use a spray can of CRC Tuner Cleaner on my radios when I'm trying to clean them and get them to work better.   But I don't think it is time for that yet.

[swood1]

Hi,

Manage to get in the workshop. My radio looks different to Dave's, which is a bit disappointing.  I attach more photos as per Scott's request.

Connections seem to be as Scott described (ie. black is positive), ground is I believe the casing.

I disaasembled the front of the radio and I tried to check the bulb.  should the bulb switch on when the knob is turned or should it be on all the time?


Steven

[swood1]

Connections on Amp rear.

[scoot]

Should the bulb switch on when the knob is turned or should it be on all the time?

Only when the switch is on (and the radio is grounded and the black wire has +12V.

[swood1]

The bulb isn't powering on but I believe my power supply is producing low amp's as I tried the same power supply on another radio and it barely powered the lamp up (it was very dim).  I have ordered a little bench top power supply, acquired a cheap aerial and bought an inline fuse holder.  Shall give it another go when I have everything to hand.

Out of interest where do I find what amps this radio should draw?  ie. for the inline fuse.  I cannot find it in the PDF downloads in the technical manual.  I would assume 5amp should do it, assuming currently only one speaker.


Regards

Steven