TECSUN 2P3 AM TRANSISTOR RADIO KIT
bought me a little transistor radio kit for my birthday and I was really chuffed with it. It's the sort of gift I would have treasured when I was a child, but back then all I got was a couple of tin cans and a piece of string 😂
Back in the 60's I was a little
obsessed with transistor radios and I still have a great fondness for them when I see them on the internet. There were some fantastic designs (I'm talking aesthetics now) and I'd love to collect some of them, but the price of them is just plain ridiculous!
So, some 50 years late, here I am with my dream boyhood birthday present. The kit is well packed and hopefully contains everything needed to complete the build. The instruction sheet is in Chinese 😦 so that would have been fun 😂. Fortunately, I found a PDF file which contains an English translation. It can be downloaded HERE.
I started the kit in the morning and expected to complete it by lunchtime but it actually took me all day, lol. It was very pleasurable and I would love to do something similar again. The kit only cost £27 - you can't complain at that!
The build requires very little in the way of tools - a soldering iron, multi-meter, pliers, cutters, a blade and small screwdrivers. I also found it beneficial to have a pair of tweezers and a round file.
The first thing I did was lay it all out and then put the relevant bits together, like resistors, capacitors, etc, to aid identification and determine values.
Identifying the resistors was a simple case of measuring them with the multi-meter. You could of course use a colour-wheel or an app like the one on Digikey.co.uk
After sorting out all the components, I cut off a part of the PCB which is later used for the Volume control...
Then it's a case of installing the AUDIO SECTION components - a few resistors, capacitors, an IC and a headphone socket.
Following that simple job, it's onto the DETECTOR SECTION which involves fitting some diodes - and this apparently, is where mistakes can easily be made. Personally, I thought it was pretty straight forward. You just have to take your time and double-check the orientation of the diodes.
With that bit done, it was time to fit more capacitors, resistors, transformers and transistors...
When that job's done, it's time to fit the volume control, complete with its 90 degree PCB section. Once it's slotted in properly, it's a simple case of soldering all the contacts and making doubly sure that the unit is perfectly square.
With the IF SECTIONS complete, it was time to install the Capacitor Gang. Quite a simple task but care had to be taken not to cause any heat damage during soldering.
The most awkward bit of the whole project was installing the ferrite bar and soldering those (6) TINY antenna wires to the PCB. After I'd finished the job, I used a hot-glue gun to stop the coils sliding up and down the bar.
That's the end of the hard bit - now it's just a case of putting the case together. Needless to say, it's best to see if it actually works before putting it all together, so I fitted some batteries, connected the speaker and switched it on. It was fine!!
After a little "fine tuning" of the transformers and gang-capacitor, I was happy with the radio and then tried it with my TECSUN AN200 loop. That made a big difference to weaker stations, but overall, the radio worked very well without.
VIDEO - Internal Antenna
VIDEO - External AN200 Antenna
For £27, I got a great day's entertainment and a great little transistor radio. Absolutely recommended. It's incredibly easy to build and despite me having very little experience, I got through it with no hiccups and no problems.
There were no missing components and everything seemed to be of good quality. I found that I had to file part of the case to make sure the tuning dial turned smoothly, but that was the one and only departure from standard.
You are recommended to run tests and take measurements throughout the build but I did none! I just didn't feel that I'd done anything wrong and it turns out I was right, lol.
Nothing better as a homemade radio. Great fun Tom ! 73, Bas
I just finished my radio and according to your pictures everything is right, but I only get a soft noise from the speaker and the volume won't turn up. I installed my resistors the way you did, does it really matter which way they are installed? Any idea what could be wrong? I'm new at this, this is my first radio. I see in your picture the the name of the ceramic filter (SFU) is facing the volume knob and tuner, mine is facing the battery, could this be the problem? Is is possible I put too much heat on the solder joints? Thanks - Tony.
Hi Tony, that SFU capacitor is a ceramic type and has no polarity requirements as far as I'm aware. I DO have something which may help you but you need to contact me via email so I can send it to you.
Drop me a line to email@example.com
And no, the resistors can be installed either way around :-)
Don't forget to close the test points
I don't understand that comment Capu.
Sir send me a crear circuit diagram please I need it now
Post a Comment