Quality control or lack of?

Amateur Radio has taken a back seat over the last few weeks with various family problems.

However yesterday, I had a bit of spare time and I was all revved up for testing a Baofeng with its battery eliminator. This is the part that takes the place of the HT battery pack and slides on the back of the radio instead of, providing regulated power from the car battery cigar lighter socket, in essence you make yourself a cheap and cheerful mobile rig.

I needed to just test it all out and check that it worked before fitting, and the MP-304 power supply which I had recently bought was still sitting on the dining room table in its box, handy for a few Volts so I thought?

Switching on the MP-304, there was no deflection of the meter, (meter switch was in the correct Volts position)? I got the DMM out, and measured the output, plenty of Volts, but still no indication on the Power supply analogue meter?

Should I return it? No chance, with all the hassle of someone having to wait in for the courier to collect, it had got to be worth a look. Anyway, I used to test power supplies by the hundreds, when I worked in the industry, so I did have a good chance maybe?

 

Quick investigation required! Took off the top of the case and I was inside, no going back now. First I measured at the rear of the meter terminals with the DMM, no Volts, nothing on the rear of meter switch that changes between Amps or Volts either. This then leads us back to the plug that plugs into CN2 on the control PCB. Just as I was about to measure at this point, I could see the Blue wire (I have marked it with a small red arrow above) was raised, with its termination tag in the plug sticking out, I unplugged the whole skt from CN2, and the Blue terminal had not been pushed home in the plug in the factory, a smart push and it  clicked in place. Plugged it back into the PCB socket and switched on, and the meter then sprung into life!

 

It does make me wonder if the Chinese really test this stuff in the factory? Time and time again I have come across problems with Chinese equipment like this, which should really be sorted in the factory before shipping, I don't believe QA exists? The problem here is, the dealer gets a bad name, and really it isn't his fault, he buys in a pallet load, one or two get put out for demonstration, and then the rest are stored ready to be shipped out in the original sealed boxes they come in.

After fixing this, it did however give me the chance to have a good look inside and see what it was made of :

Build quality really wasn't too bad, a nice hefty transformer feeding a quality bridge rectifier, control board (which I have already mentioned), that sets up the limits and then drives the outputs. A good quality heatink blown at by a fan, which is triggered by a stat when the temp gets to a certain level.

Cased back up, I was then back to the point where I had started at a couple of hours earlier, testing the Baofeng:

More power for the shack.

A refurbishment of the shack is long overdue, and some advanced birthday money prompted me to take up one of ML&S recent deals. I had been looking at various Linear power supplies to feed the new layout, and the MP-304mkII would fit the requirement of servicing the array of rigs I have to feed.

Ordering was quick which I did over over the phone,  as normal with Martin Lynch & Sons, the faultless delivery was on time! Infact so quick! I had forgotten to tell the XYL, so she was surprised by the delivery.

The MP304 is sold as a 30A supply, that does 15A continuous, and 20A for 15minutes @13.8V. Supplied with a mains voltage of 230V 50Hz.

There are various output connections on the front, including a handy Cigar lighter socket that can supply 10A.

The supply is variable by an adjustable pot on the front panel, which is biased in the middle of its range to set the supply at the nominal 13.8V. The output is adjustable between 1.5V & 15V DC. With a sliding scale of V/I) (Don't expect 15A Max at 5V as this works out at about 7A)

The large easy to read analogue Meter is switchable either to Volts or Amps.  

Supply regulation is better than 1% and a noise figure <10mV is quoted.

We will see how this performs when I will load it up and do a few measurements in the next day or so.

A short form manual is supplied, a circuit diagram would of been useful for servicing in the future. (I have not seen one on the web?)

First looks are good, and not bad for the money of £99!