For sale: Old valve free radio advice and help in bringing back to life these classics.

Hi Mike,

This may not be worth your interest but I have a Grundig Yacht Boy 400 radio, analogue style, probably dating back to the early 80s. It hasn't been used in a very long while and works (?) after a fashion.  FM working OK. Nothing on LW or MW. SW just coming back to life but comes and goes. I'm not savvy on radio but I'm an IT engineer and know my way around computer internals. Can you advise as to what I can try to restore functionality to this set ?

Many thanks in advance..

Mervyn 

I had a Yacht boy from the 70s which I replaced with a Sony 7600 in the early 90s, I still have have it now, had a lot of Cap changes but it is still going strong.

I think the same thing applies, check for corrosion of the tracks on the PCB and and areas where there might be current

flow between tracks due to corrosive effects. The number one problem are the electrolytics, due to them drying out or leaking electrolyte. Make a list of them and change them all, Yes ALL. clean the pcb where they were removed with medical alcohol before replacing them. Special attention to polarities of the capacitors. Clean the waveband switches with proper contact cleaner.

These little Grundigs  were quite useful little sets.

To be really smart apply a low voltage in the correct polarity (say 3V) to the new electrolytics to form them. Make sure you discharge them (Short them ) before fitting them to the radio.

Good luck, let me know how it goes. and if you need any more specific help.

Just a thought The Yacht boy was a transistor version ?

Must bring an old one I have out with me next time I’m driving over, that’s if the missus hasn’t thrown it out. It is pretty old and plugs into the bulb socket rather than a socket. Haven’t tried it for years but last time only a light came but no sound. 

Hi Mike, yes transistor version I guess. Following your  advice I used contact cleaner on the buttons and slides and, seemingly also important, the battery bay. Now I'm getting something on LW and MW also. Perhaps better connections = more power needed to work properly. I will find a mains charger and try that to see. Do you know if the frequency display should be illuminated as it is not at the moment ?

Many thanks for your advice..

Rgds Mervyn

Replacing the caps is the most important because of the ones that may have leaked and caused corrosion of the pcb tracks and spurious resistive paths between components.

My 7600 was a nightmare because the caps were surface mounted, If I remember correctly the Grundig had normally mounted components (Through board) It is over 40 years since I had mine...................... so I hope I may be forgiven if I am wrong.

Hi Pete, I'm fine thanks. Hope you are also and ready for the xmas break. WRT capacitors, I've been able to download a copy of the repair manual for this Yacht Boy 400 which is a 1980 model. I'll be able to check the capacitor spec from that hopefully. No button for frequency display light that I can see but once confident to try the adaptor should be as you have said. I had  a Party Boy in the early seventies which was a great radio. Again just disappeared somewhere in the years. Thanks for your suggestion !! Best regards, Mervyn

Hi Mike, many thanks for the information. I will hopefully find more once I've looked at the repair manual that I've downloaded. With the casing dismantled should be able to spot any corrosion to the PCB tracks. Hopefully, a straightforward job overall but need to check availability of the replacement caps. Once again thanks for the info and I will post anyway. Best regards and for the xmas period... Rgds Mervyn  

Basically it is only the electrolytic or tantalum Caps that are problematic with age etc, the smaller ceramic or polyester ones are usually not a problem with transistor sets. For a source for the electrolytic capacitors try RAYTE in Orihuela (buying on Amazon/Ebay is cheaper but delivery times are very long, I bought some (47uf 450V) from Rayte for an old valve radio a couple of months ago. The 6 caps cost about 5 Euros, reasonable price  but the postage was a bit excessive 5 Euros and quite slow, 1 week. Look on their site, but it may well be worth while going to their shop to get the bits you want. I think the radio is quite easy to take apart so you can see what working voltage the caps are and how big they are. Eg, if one is a 6V and you buy a 25V version it may be a bit too big, although Capacitors 50 years ago were considerably bigger than their modern day counterparts.

Anyway good luck and let us know how it goes.

MM