Grundig yacht boy 210

[makeitwork]

Hi, I have one of these sets (wood effect facia) and the volume control is very intermittent, noisy.

How easy is it to take this out and repair / replace it ?. Does the whole chassis have to come out ? Any advice or tips would be welcome...

Thanks

[G4YVM David]

Try squirting switch cleaner inside it rather than removing it

[makeitwork]

Thanks David, that worked, nice and smooth now but hasn't fixed the problem as I thought it would. As soon as I start turn the volume up and there's plenty of it, the sounds becomes distorted on all wavebands regardless of which station is tuned in. Could this be a problem with the AF amp ?

Paul

[terrykc]

Originally Posted by G4YVM David

Try squirting switch cleaner inside it rather than removing it

Yes, but he needs to get it apart first!

Pull off the knobs.

You should find two chrome raised countersunk screws holding the dial on then you will be able to remove the chassis securing screws and lift out the complete chassis.

As well as the volume control problem, make sure that the geared tuning reduction drive which forms an integral part of the tuning gang is well lubricated - they have a habit of seizing up solid!

[makeitwork]

Hi,

The set is sounding slightly better. Have set up the quiescent current of o/p transistors to 5.5ma as per service sheet, but although volume of set appears to be louder its still distorted.
The next step on the service sheet is setting up of i.f. amps. It says connect voltmeter across R23 and adjust R28 for 1.3v. But R28 on my set is a fixed resistor not a pre-set. Is this a misprint. Does it mean put voltmeter across R23 which is a pre-set and adj this for 1.3v ?. Any advice would be appreciated,

Thanks

[simpsons]

I would be very wary of "setting up" the IF strip given you have not proved it is at fault. Is it the AM or FM IF or front end that is faulty or is this a well meaning guess?

May I suggest you feed an known good AF signal into the DIN socket This will soon tell you what is going on with the audio section of the receiver. Twiddling anything for good or better sound will cause you grief more than you can imagine.



Chris

[HamishBoxer]

Unless been previously "twiddled" the IF's will be normally fine on nearly any set.

[ms660]

Originally Posted by makeitwork

The next step on the service sheet is setting up of i.f. amps. It says connect voltmeter across R23 and adjust R28 for 1.3v. But R28 on my set is a fixed resistor not a pre-set. Is this a misprint. Does it mean put voltmeter across R23 which is a pre-set and adj this for 1.3v ?.

It's a misprint so far as I can tell, the schematic and the board layout confirms that.

The voltage is measured across R28 and adjusted with R23.

Lawrence.

[terrykc]

Originally Posted by makeitwork

As soon as I start turn the volume up and there's plenty of it, the sounds becomes distorted ...

Paul, if I interpret your post correctly you are saying that the sound is undistorted at low levels in which case there is absolutely no way that the problem occurs in the IF or RF stages, so leave well alone.

Do you have an oscilloscope? If so, follow the signal through the AF stages to determine where the problem starts. Alternatively, can you connect a probe to the input of a suitable external AF amplifier and perform the same check aurally?

Do voltage checks in the AF amplifier reveal anything?

[GeoffK]

Has the loudspeaker been checked? The Grundig Yacht Boy is artificially bass heavy unless the tone control knob is pulled out. This could make the sound seem distorted at high volume levels. The loudspeaker is a high quality unit but can still go faulty.

[ms660]

And don't forget the supply is 7.5 volts for quiescent adjustments.

Lawrence.