yacht boy 209 - current 'leakage'

[yestertech]

I've just found that my recently refurbished yacht boy 209 has chewed through the new "D" batteries when left idle for a week.
The radio was not switched on.
The symptoms were low volume /distortion and complete failure if the dial light button was pressed in
I suspected the batteries but as a check connected a PP9 to the external PSU adaptor. This restored normal operation
The radio pulls around 100 + ma when on low volume, but to my surprise when switched off there is still a drain of around 65 ma !
I can't see anything on the schematic which could cause this
Anyone else come across this problem ?
I don't know this set's quirks well enough !

It is a truly superb radio though

Andy

[Tom_I]

I think you must have a fault somewhere.

I've just checked my Yacht Boy 210, which is similar, and it's drawing about 22 mA on low volume, and nothing at all when switched off.

Tom

[OErjan_S]

leaky capacitor?
something shorting the circuit?

[yestertech]

Thanks folks
I can't see anything which is in circuit with the power "off" hence the puzzle. It would also seem that when 'on' the current drain is excessive also ....HO HUM
....and yet it works brilliantly


Andy

[Darren-UK]

Try disconnecting the dial lamp switch and then measuring the current, with the radio on and off. It sounds like a permanent s/c exists at or near that switch, probably caused by something as simple as a stray strand of wire or even a tiny blob of solder that's been rattling around inside the radio.

[paulsherwin]

I agree with everybody else, 100mA is far too much for normal operation. I would guess that something is drawing 65mA all the time, even when the set is switched off. Have you done a simple resistance test across the battery terminals with the set switched off?

Paul

[Steve_P]

Clean and examine the circuit board (PCB) and the push button switch.

There's some sort of external power adaptor too - I can't read German! - look here too.

It can't be much.

Cheers,

Steve P.

[yestertech]

Doh !! I've just realised - when the external PSU connection is used
( aka PP9 ) it permanently powers the scale lamp. Wally !
That'll teach me to test it from the rear !!
So my actual low volume current drain is the difference between the two readings, ie about 35ma
I will have to uncase it ( ho hum ) and measure the current drain from the holder assembly for the D cells with the set switched off.
I'll also check the OP stage quiescent adjustment, which I've had no cause to touch.
Maybe I just got a bad bacth of D's

Andy

[russell_w_b]

Originally Posted by setsappeal

I will have to uncase it ( ho hum ) and measure the current drain from the holder assembly for the D cells with the set switched off.
Andy

If you get yourself a sliver of double-sided copper-clad PCB about 1/2-Inch wide by whatever long and solder a wire to each side connected to your metimulter, you can measure current-drain simply by pushing the PCB between the +VE terminal of one cell and the -VE terminal of the adjacent one.

[Tom_I]

It's dead easy with these Grundigs. Turn the set upside down and remove the battery cover. Then just connect your meter between the two exposed battery ends.

[paulsherwin]

The quiescent current is probably about right if the set is drawing about 35mA at low volume. It was out by a factor of 10 on my Yachtie - presumably some assembly technician in Portugal had had his meter set to the wrong range, and quality control didn't pick it up. It was great for battery life but not so good for crossover distortion

Paul

[yestertech]

Originally Posted by Tom_I

It's dead easy with these Grundigs. Turn the set upside down and remove the battery cover. Then just connect your meter between the two exposed battery ends.

Very clever ! I wish I'd thought of it ! A.