Grundig Yacht Boy 210

[LyntonP]

Just took possession of one of these fine radios. Always wanted one as a lad but could never afford one. Tried the radio with new batteries but a devil of a job to keep them connected! There is a separate connection inside the radio with similar but larger and wider spaced terminals to those found on a 9 volt battery. Were these for the Grundig power supply or a long gone larger battery, and do the terminals conform to the similar but smaller connections of a 9 volt battery with regards to polarity? The wires from this connector go to the mains? /battery switch on the back of the set and then on to the socket for an external supply before going to the circuit board. I can soon construct a 9 volt regulated supply but want to be sure about the polarity.
Didn’t get any sound on any band other than a little “bump” when I turned the radio on.
Lynton

[Nuvistor]

Service manual.
https://www.service-data.com/product...98/3481/m12598

[Viscount]

the larger connection is for a pp9 you can get converters on ebay which take 6 AA batts

[Jonster]

There was a dedicated mains adaptor for these, I think it was the TN12, I have one somewhere. There are two positive terminals, one of which goes to the dial light which can then be operated without switching on the radio when on mains power.

There's one shown here: http://www.satellitradio.it/radio-mi...ndig-tn12-1971

[Viscount]

the converters are listed on ebay under battery holders,just make sure you get the correct one there are many listed

[Tom_I]

As stated, the connector inside the Yacht Boy 210 is intended for use with the Grundig TN12 mains power supply unit. This is the same size as a PP9 battery, and uses the same snap connector.

It's perfectly feasible to put a PP9 battery in this compartment, rather than use 6 "D" cells in the main battery box. However, you should be aware that, if the bulb is intact, the dial illumination will be on all the time if the set is powered via this connector, so the battery will run down even if the set is switched off.

[LyntonP]

More investigations on the set. Checked the voltages as shown on the manufacturers circuit diagram.These seem a little higher than suggested but not sure if I should have used a lower supply voltage? 7.5 volts instead of 9 volts?
checked the electrolytic caps on the output stage but I only have a dvm.
C61 3.2K ohms, C62 3K, C63 5K, C660.8K. Does this suggest they are kaput?
If I connect the psu to the battery supply terminals and set the ac?mains? switch to battery and then operate the switch in what would be the external psu plug the radio works for a second and then fades.
I have cleaned all the switches and pots.
Part of the plastic chassis was broken, so now waiting for the glue to dry.
Lynton

[John Caswell]

The TN 12 has three terminals 2 +ve and 1 -ve.
When used with a Yacht Boy if the radio is off using the on/off push button on the top, and the power line switched on using the switch on the TN12 cable then the dial lights come on independent of the radio.
This feed is from the central +ve terminal and the -ve terminal. The radio can then be powered powered up/down using the on/off push button and this feed comes from the outer +ve terminal and the -ve terminal.
The output of the TN12 for the radio is 9V, and as Tom_I says you can either use a TN12 or a PP9 or 6 "C" cells. However with the battery option you do not have permanently on dial lights.

John

[LyntonP]

To avoid confusion I am using my own 9 volt power supply not a Grundig unit. I am supplying 9 volts to the normal battery compartment terminals. So the radio thinks it is running on dry cells.
Lynton

[LyntonP]

Changed electrolytic capacitors C61, 62, 63, and 66 (manufacturers sheet).
Removed and stripped plug for connection of power pack. Set of contacts inside very corroded but cleaned them with very fine wet and dry and switch cleaner. Power was not getting from battery compartment due to corrosion, now ok.
Radio would still not play but if I disconnected power supply rather than turn of with switch radio would work for a second. Reduced voltage from power supply from 9 to 8 volts and radio works on FM but not on any other bands.
Any suggestions?
Lynton

[Nuvistor]

An RF/IF stage could be going unstable with the higher voltage, check decoupling capacitors etc.
The AM fault could be the LO not working, try and find it using another radio. Tune the Grundig to 1Mhz and listen using the other radio around 1.46Mhz if the IF is 460Khz.

[LyntonP]

Hi Frank Did as you suggested and I could hear the LO. Further examination of the circuit board followed. When I touched one of the soldered joints the set came to life! On examination it was a connection to R23 a potentiometer. I gave the pot a little tweak and the volume increased dramatically. I peaked it for max volume then turned the voltage on the PSU back to 9v and the set works fine on all bands. Not really sure what the function of R23 is? But set is now on test.
Scale lamp has gone Osram 7 volt miniature which I suppose are unobtainable?
Need some new knobs to finish it off.
Thanks again for the help
Lynton

[ms660]

R23 sets the bias for T5 and T4, it shows where to measure the voltage on the schematic, 1.3 volts across R28 with a B+ (supply) voltage of 7.5 volts.

Lawrence.

[LyntonP]

Good advice Lawrence. I cannot read this on my schematics but to be fair it is mentioned on an earlier page of the service data. I will check this tomorrow.
Lynton

[LyntonP]

Reset bias voltage to recommended value. Radio working fine now.
Lynton

[Nuvistor]

[LyntonP]

Originally Posted by Nuvistor

Thanks Frank found a replacement scale lamp came from a BMW R65 motorcycle.
All I need now are some replacement knobs.
Lynton